Patent Application
20210380661
The present invention relates in general to the field of immunology, and more particularly to novel methods for expressing, purifying, and post-translationally modifying eukaryotic cell-derived major histocompatibility complexes.
The present application includes a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Oct. 14, 2019, is named TECH2131WO_SeqList.txt and is 114, kilo bytes in size.
Without limiting the scope of the invention, its background is described in connection with methods of making eukaryotic cell-derived major histocompatibility complexes (MHC).
The major histocompatibility complex (MHC) class I and II molecules play an integral role in T cell development and peripheral effector responses (Alcover et al., 2018). MHC class I is retained on the plasma membrane of nucleated cells and consists of a multi-unit heavy chain whose tertiary structure is stabilized by β2 microglobulin through non-covalent forces (Wieczorek et al., 2017). To provide specific binding to antigen specific CD8+ T cells, MHC class I usually retains a short 8-10 amino acid peptide within the MHC peptide binding groove that is derived from degraded intracellular proteins (hereafter referred to as peptide/MHC).
The present understanding of basic T cell properties and dynamics under a variety of normal and diseased settings has been greatly advanced by the ability to produce and purify peptide/MHC for use in assays to specifically engage the T cell receptor (TCR). Arguably the most widespread approach incorporates fluorochrome-conjugated peptide/MHC multimers (e.g., tetramers) for analyzing or isolating antigen-specific CD8+ T cells from biological samples (Khaimar et al., 2018; Soen et al., 2003). Peptide/MHC generation has continued similarly to the process outlined in the landmark work by Altman and colleagues (Altman et al., 1996). Briefly, 02 microglobulin and MHC class I heavy chain (containing a BirA tail) are individually expressed in E. coli and later purified from inclusion bodies through a laborious lysis/solubilization process. A defined MHC class I peptide is then added alongside β2 microglobulin and heavy chain in a precise folding reaction mixture that requires several days to complete prior to affinity chromatography (AC) purification of properly folded peptide/MHC and later biotinylation steps. Although this standard production process works to eventually yield excellent reagents for immunologic assays, there exist a number of major disadvantages. Namely, the standard method is [i] time consuming, [ii] requires substantial levels of raw ingredients (particularly purified MHC class I peptide), and [iii] cannot guarantee large-scale production of properly folded peptide/MHC molecules based on predicted peptide binders. For example, it is extremely difficult to stably produce MHC molecules bearing peptides with low-to-moderate affinity to the MHC peptide-binding groove.
Prior attempts to make peptide/MHC complexes include those of White and colleagues, which designed a soluble HIV-reactive MHC class I molecule (consisting of free heavy chain+linked peptide-β2 microglobulin) for expression in baculovirus, which was capable of biotinylation/multimerization and identifying a particular T cell hybridoma by flow cytometry (White et al., 1999). An additional approach was by Greten and colleagues performed standard plasmid DNA transfection to produce a peptide-β2 microglobulin-heavy chain linked protein in J588L cells that was only capable of dimerization due to mouse IgG fusion (Greten et al., 2002).
Thus a need remains for novel compositions, methods, vectors, cells, etc., that include novel constructs that allow for the production of peptide-MHC complexes in eukaryotic cells.
In one embodiment, the present invention includes a fusion protein comprising a peptide, a first flexible linker, a β2-microglobulin domain, a second flexible linker, a soluble major histocompatibility complex (MHC) heavy chain and a peptide tag. In one aspect, the peptide is an immunogenic peptide epitope. In another aspect, the MHC is a human, mouse, rat, hamster, horse, pig, cow, simian, avian, or chimeric MHC. In another aspect, the MHC is Class I MHC. In another aspect, the does not include a transmembrane sequence. In another aspect, the peptide tag is selected from wherein the peptide tag is selected from at least one of: a BirA tail, a myc, a FLAG, a glutathione-S-transferase, a His tag, a maltose binding protein, hemagglutinin (HA)-tag, a V5 tag, a T7 tag, a V9 tag, a NusA-tag, a thioredoxin-tag, or a fluorescent protein-tag, a Her2/neu-tag, a CD20-tag, or a GFP-tag. In another aspect, the first, the second, or both the first and second flexible linkers comprise glycine, serine or both glycine and serine and comprise 5 to 40 residues, but may be 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39. In another aspect, the peptide is 8 to 16 residues long. In another aspect, the peptide is selected from at least one of: ABL1; ACPP; Ad5 ElA; AdV 5 Hexon; AdV Hexon; Ag85A; alfa fetoprotein; ASP-2; BA46; BALF4; BAP31; BCL-2; BCL-2A1; BCL-2L1; BCL-X; BCR-ABL; bcr-abl 210 kD fusion protein; Beta-gal; BGLAP; BMI1; BMLF1; BMRF1; BNP; BRAF 27; BRLF1; bZIP factor; BZLF1; C1orf59; CAMEL; Carbonic anhydrase; CB9L2; CD105; CD33; CD59; CEA; CEACAM; Chondromodulin; circadian clock protein PASD1; CP; CPS; cyclin-dependent kinase 4; CYP190; Cytochrome p450; DEP DC1; DLK1; Dutpase; E6; E7; EBNA 1; EBNA 3A; EBNA 3B; EBNA 6; EBV BRLF1; EBV EBNA3A; EBV LMP2; EDDR1; EGFR; EMNA 3A; EMV-1; Enhanced Green Fluorescent Protein; Env; EphA2; Erkl; ESAT-6; EZH2; FAPa; FLT1; FOLR1; FOXM1; G250; GAD65; Gag; Gag-pol; Glypican 3; gp; gp100; gp33 (C9M); GPC3; H250; HA-1; HA-2; HA-8; HBB; HBsAg; HBV core; HBV polymerase; HBV surface antigen; HCMV IE1; HCMV pp65; HCV core; HCV E; HCV NS3; HCV NS4b; HCV NS5a; HCV NS5B; Heparanase; HER2; HER-2/neu; Histocompatibility antigen 60; HIV gag p24; HIV nef; HIV pol; HIV-1 env gp120; HIV-1 IIIB gp120; HIV-1 nef, HIV-1 p17; HIV-1 RT; HIV-1 US4 gp120; HJURP; HLA-A leader sequence peptide; HLA-A2; HLA-Cw3; Chlamydia trachomatis MOMP; HM1.24; HMMR; HMOX1; HO-1; hPSA; HPV 16 E6; HSP105; HSP90 alpha; hTERT; hTOM34p; hTRT; H-Y; IA-2; IAPP; IDO; IE-1; IE62; IGF; IGRP; IL13r; IL13Ra; Ilr1; Influenza A (PR8) NP; Influenza A MP; Influenza A MP1; Influenza A MP2; Influenza A NP; Influenza A PB1; INFγR; Insulin; Interferon gamma inducible protein (GILT) 30; IRS-2; ITGB8; K8.1; KIF20A; KLK; KLK3; L1; LANA; Large T antigen; Lengsin; Listeria monocytogenes Listeriolysin; LTVIN; LMP-1; LMP-2; LMP-2A; LMP-2A; LY6K; m139; m141; m145; M164; M2-1; M38; M45; M57; MAGE-1; MAGE-10; MAGE-3; MAGE-4; MAGE-A1; MAGEA2; MAGEA3; MAGE-A5; MAGE-C1; MAGE-C2; MART-1; MC38 adpgk neoantigen; MC-38; MCL-1; MCMV IE1; MELK; Mena; Middle T antigen; Midkine; miHAg SMCY; MOG precursor; MP; MPP11; MS4A1; MSLN; Mtb 16 kDa; Mtb 19 kDa; Mtb85A; mTERT; Mucin; muFAPα; MuLV env; Murine Survivin; MYBPC-2; Mycobacterium bovis antigen 85-A; Mycobacterium tuberculosis ESAT-6; Mycobacterium tuberculosis TB10.4; Myelin basic protein; ND; NEF; NEF; Neu/Her-2/Erbb2 proto-oncoprotein; NG2; Non muscle Myosin-9; Non-muscle Myosin; NP; NP396; NP52; NPM1; NRP-1; NRP-2; NRP-V7 superagonist peptide 8.3 Tg NOD mouse; NS3; Nucleocapsid; Nuf2; NY-ESO-1; OVA; Ovalbumin (subdominant); P1A; β2X5a; p53; p56; P79; PAP-3; PASD1; PAX-5; p-Cadherin; PDGFRbeta; PLAC1; PLAM csp; Plasmodium berghei ANKA acid phosphatase; Plasmodium berghei CSP; Plasmodium CSP; Plasmodium falciparum CSP; Plasmodium falciparum Liver stage antigen; PolA; Polymerase; Polyprotein; pp65; PPE; Pr1; PRAME; Prominin1; PSA; PSCA; PSM β2; PSMA; RGS5; RhoC; RNF43; RSV A strain F protein; RSV NP; RT; S protein; SAA; SART3; Sialidases; SIV gag; SMCY; Spike GP; STEAPI; Surface IgG (sA20-Ig) of A20; Survivin; Survivin-3a; SV40 T antigen; TACE; TARP; TARP 2M; Tax; TB10.3-4; Telomerase; TEM1; tgd057; TGFβ; TNPO3; topII; TPBG; TPR-protein; TRAG; TRP2; Trypanosoma cruzi ASP-2; Trypanosoma cruzi SP; TTK; Tyrosinase; Tyrosine-3-hydroxylase; Ubiquitin; UL105; UL138; UL44; USP9Y; V131; Vaccinia virus Copenhagen Protein G5; Vaccinia virus Host range protein 2; VACCL3_100; VEGFR1; VEGFR2; VEGFR2/KDR fragment 1; Vif; Vinculin; VP1; Vpu; VSV N; West Nile virus NY-99 polyprotein precursor; West Nile Virus polyprotein; WT1; Yellow Fever Virus 17D polyprotein; or ZnT-8. In another aspect, the MHC is selected from at least one of H-2 Db, H-2 Dd; H-2 Dk; H-2 Kb; H-2 Kd; H-2 Kk; H-2 Ld; HLA-A*0101; HLA-A*0201; HLA-A*0301; HLA-A*1101; HLA-A*2301; HLA-A*2402; HLA-A*2902; HLA-A*6801; HLA-B*0702; HLA-B*0801; HLA-B*1501; HLA-B*2705; HLA-B*3501; HLA-B*4001; HLA-B*5101; or HLA-E*0101. In another aspect, the peptide is at least one of SEQ ID NO:1-599.
In another embodiment, the present invention includes a nucleic acid that expresses a fusion protein comprising a peptide, a first flexible linker, a β2-microglobulin domain, a second flexible linker, a soluble major histocompatibility complex (MHC) heavy chain and a peptide tag. In one aspect, the peptide is an immunogenic peptide epitope. In another aspect, the MHC is a human, mouse, rat, hamster, horse, pig, cow, simian, avian, or chimeric MHC. In another aspect, the MHC is Class I MHC. In another aspect, the MHC does not include a transmembrane sequence. In another aspect, the peptide tag is selected from at least one of: a BirA tail, a myc, a FLAG, a glutathione-S-transferase, a His tag, a maltose binding protein, hemagglutinin (HA)-tag, a V5 tag, a T7 tag, a V9 tag, a NusA-tag, a thioredoxin-tag, or a fluorescent protein-tag, a Her2/neu-tag, a CD20-tag, or a GFP-tag. In another aspect, the first, the second, or both the first and second flexible linkers comprise glycine, serine or both glycine and serine and comprise 5 to 40 residues. In another aspect, the peptide is 8 to 16 residues long. In another aspect, the peptide is selected from at least one of: ABL1; ACPP; Ad5 ElA; AdV 5 Hexon; AdV Hexon; Ag85A; alfa fetoprotein; ASP-2; BA46; BALF4; BAP31; BCL-2; BCL-2A1; BCL-2L1; BCL-X; BCR-ABL; bcr-abl 210 kD fusion protein; Beta-gal; BGLAP; BMI1; BMLF1; BMRF1; BNP; BRAF 27; BRLF1; bZIP factor; BZLF1; C1orf59; CAMEL; Carbonic anhydrase; CB9L2; CD105; CD33; CD59; CEA; CEACAM; Chondromodulin; circadian clock protein PASD1; CP; CPS; cyclin-dependent kinase 4; CYP190; Cytochrome p450; DEP DC1; DLK1; Dutpase; E6; E7; EBNA 1; EBNA 3A; EBNA 3B; EBNA 6; EBV BRLF1; EBV EBNA3A; EBV LMP2; EDDR1; EGFR; EMNA 3A; EMV-1; Enhanced Green Fluorescent Protein; Env; EphA2; Erkl; ESAT-6; EZH2; FAPa; FLT1; FOLR1; FOXM1; G250; GAD65; Gag; Gag-pol; Glypican 3; gp; gp100; gp33 (C9M); GPC3; H250; HA-1; HA-2; HA-8; HBB; HBsAg; HBV core; HBV polymerase; HBV surface antigen; HCMV IE1; HCMV pp65; HCV core; HCV E; HCV NS3; HCV NS4b; HCV NS5a; HCV NS5B; Heparanase; HER2; HER-2/neu; Histocompatibility antigen 60; HIV gag p24; HIV nef; HIV pol; HIV-1 env gp120; HIV-1 IIIB gp120; HIV-1 nef; HIV-1 p17; HIV-1 RT; HIV-1 US4 gp120; HJURP; HLA-A leader sequence peptide; HLA-A2; HLA-Cw3; Chlamydia trachomatis MOMP; HM1.24; HMMR; HMOX1; HO-1; hPSA; HPV 16 E6; HSP105; HSP90 alpha; hTERT; hTOM34p; hTRT; H-Y; IA-2; IAPP; IDO; IE-1; IE62; IGF; IGRP; IL13r; IL13Ra; Ilr1; Influenza A (PR8) NP; Influenza A MP; Influenza A MP1; Influenza A MP2; Influenza A NP; Influenza A PB1; INFyR; Insulin; Interferon gamma inducible protein (GILT) 30; IRS-2; ITGB8; K8.1; KIF20A; KLK; KLK3; L1; LANA; Large T antigen; Lengsin; Listeria monocytogenes Listeriolysin; LIVIN; LMP-1; LMP-2; LMP-2A; LMP-2A; LY6K; m139; m141; m145; M164; M2-1; M38; M45; M57; MAGE-1; MAGE-10; MAGE-3; MAGE-4; MAGE-A1; MAGEA2; MAGEA3; MAGE-A5; MAGE-C1; MAGE-C2; MART-1; MC38 adpgk neoantigen; MC-38; MCL-1; MCMV IE1; MELK; Mena; Middle T antigen; Midkine; miHAg SMCY; MOG precursor; MP; MPP11; MS4A1; MSLN; Mtb 16 kDa; Mtb 19 kDa: Mtb85A; mTERT; Mucin; muFAPα; MuLV env; Murine Survivin; MYBPC-2; Mycobacterium bovis antigen 85-A; Mycobacterium tuberculosis ESAT-6; Mycobacterium tuberculosis TB10.4; Myelin basic protein; ND; NEF; NEF; Neu/Her-2/Erbb2 proto-oncoprotein; NG2; Non muscle Myosin-9; Non-muscle Myosin; NP; NP396; NP52; NPM1; NRP-1; NRP-2; NRP-V7 superagonist peptide 8.3 Tg NOD mouse; NS3; Nucleocapsid; Nuf2; NY-ESO-1; OVA; Ovalbumin (subdominant); P1A; β2X5a; p53; p56; P79; PAP-3; PASD1; PAX-5; p-Cadherin; PDGFRbeta; PLAC1; PLAM csp; Plasmodium berghei ANKA acid phosphatase; Plasmodium berghei CSP; Plasmodium CSP; Plasmodium falciparum CSP; Plasmodium falciparum Liver stage antigen; PolA; Polymerase; Polyprotein; pp65; PPE; Pr1; PRAME; Prominin1; PSA; PSCA; PSM β2; PSMA; RGS5; RhoC; RNF43; RSV A strain F protein; RSV NP; RT; S protein; SAA; SART3; Sialidases; SIV gag; SMCY; Spike GP; STEAPI; Surface IgG (sA20-Ig) of A20; Survivin; Survivin-3a; SV40 T antigen; TACE; TARP; TARP 2M; Tax; TB10.3-4; Telomerase; TEM1; tgd057; TGFβ; TNP03; topII; TPBG; TPR-protein; TRAG; TRP2; Trypanosoma cruzi ASP-2; Trypanosoma cruzi SP; TTK; Tyrosinase; Tyrosine-3-hydroxylase; Ubiquitin; UL105; UL138; UL44; USP9Y; V131; Vaccinia virus Copenhagen Protein G5; Vaccinia virus Host range protein 2; VACCL3_100; VEGFR1; VEGFR2; VEGFR2/KDR fragment 1; Vif, Vinculin; VP1; Vpu; VSV N; West Nile virus NY-99 polyprotein precursor; West Nile Virus polyprotein; WT1; Yellow Fever Virus 17D polyprotein; or ZnT-8. In another aspect, the MHC is selected from at least one of H-2 Db, H-2 Dd; H-2 Dk; H-2 Kb; H-2 Kd; H-2 Kk; H-2 Ld; HLA-A*0101; HLA-A*0201; HLA-A*0301; HLA-A*1101; HLA-A*2301; HLA-A*2402; HLA-A*2902; HLA-A*6801; HLA-B*0702; HLA-B*0801; HLA-B*1501; HLA-B*2705; HLA-B*3501; HLA-B*4001; 1HLA-B*5101; or HLA-E*0101. In another aspect, the peptide is at least one of SEQ ID NO:1-599.
In another embodiment, the present invention includes a method of making a soluble eukaryotic-derived peptide/MHC complex comprising: expressing in a cell a fusion protein comprising a peptide, a first flexible linker, a β2-microglobulin domain, a second flexible linker, a soluble major histocompatibility complex (MHC) heavy chain and a peptide tag. In another aspect, the method further comprises isolating the fusion protein from a supernatant. In another aspect, the method further comprises forming dimers, trimers, tetramers, or multimers of the fusion protein by mixing the fusion protein with one or more agents that bind to two or more fusion proteins. In another aspect, the agent is selected from an antibody, a cross-linking agent, a ligase, an avidin, a streptavidin, a Protein A, or a J-chain. In another aspect, the peptide is an immunogenic peptide epitope. In another aspect, the MHC is a human, mouse, rat, hamster, horse, pig, cow, simian, avian or chimeric MHC. In another aspect, the MHC is Class I MHC. In another aspect, the MHC does not include a transmembrane sequence. In another aspect, the peptide tag is selected from at least one of a BirA tail, a myc, a FLAG, a glutathione-S-transferase, a His tag, a maltose binding protein, hemagglutinin (HA)-tag, a V5 tag, a T7 tag, a V9 tag, a NusA-tag, a thioredoxin-tag, or a fluorescent protein-tag, a Her2/neu-tag, a CD20-tag, or a GFP-tag. In another aspect, the irst, the second, or both the first and second flexible linkers comprise glycine, serine or both glycine and serine and comprise 5 to 40 residues. In another aspect, the peptide is 8 to 16 residues long.
In another embodiment, the present invention includes a cell line expressing a fusion protein comprising a fusion protein comprising a peptide, a first flexible linker, a β2-microglobulin domain, a second flexible linker, a soluble major histocompatibility complex (MHC) heavy chain and a peptide tag. In one aspect, the fusion protein is integrated into the genome by co-transfecting a fusion protein expressing vector with a transposase vector that expresses a transposase and wherein the fusion protein expressing vector, the transposase vector, or both further comprise a selectable marker. In one aspect, the peptide is an immunogenic peptide epitope. In another aspect, the MHC is a human, mouse, rat, hamster, horse, pig, cow, simian, avian, or chimeric MHC. In another aspect, the MHC is Class I MHC. In another aspect, the MHC does not include a transmembrane sequence. In another aspect, the peptide tag is selected from at least one of: a BirA tail, a myc, a FLAG, a glutathione-S-transferase, a His tag, a maltose binding protein, hemagglutinin (HA)-tag, a V5 tag, a T7 tag, a V9 tag, a NusA-tag, a thioredoxin-tag, or a fluorescent protein-tag, a Her2/neu-tag, a CD20-tag, or a GFP-tag. In another aspect, the first, the second, or both the first and second flexible linkers comprise glycine, serine or both glycine and serine and comprise 5 to 40 residues. In another aspect, the peptide is 8 to 16 residues long.
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures and in which:
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a”, “an” and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not limit the invention, except as outlined in the claims.
The present invention includes compositions, vectors, cells, and methods of making MHC class I-specific reagents such as fluorescently-labeled multimers (e.g., tetramers) that can be used to study CD8+ T cells under normal and diseased states. However, recombinant MHC class I components (comprising MHC class I heavy chain and p2 microglobulin) are usually produced in bacteria following a lengthy purification protocol that requires additional non-covalent folding steps with exogenous peptide for complete molecular assembly. The present inventors have developed an alternative and rapid approach to generating soluble and fully-folded MHC class I molecules in eukaryotic cell lines (such as CHO cells) using, e.g., a Sleeping Beauty transposon system. Importantly, this method generates stable cell lines that reliably secrete epitope-defined MHC class I molecules into the tissue media for convenient purification and eventual biotinylation/multimerization. Additionally, MHC class I components are covalently linked, providing the opportunity to produce a diverse set of CD8+ T cell-specific reagents bearing peptides with various affinities to MHC class I.
As used herein, the term “gene” refers to a functional protein, polypeptide or peptide-encoding unit. As will be understood by those in the art, this functional term includes both genomic sequences, cDNA sequences, or fragments or combinations thereof, as well as gene products, including those that may have been altered by the hand of man. Purified genes, nucleic acids, protein and the like are used to refer to these entities when identified and separated from at least one contaminating nucleic acid or protein with which it is ordinarily associated.
As used herein, the term “vector” is used in reference to nucleic acid molecules that transfer DNA segment(s) from one cell to another. The vector may be further defined as one designed to propagate specific sequences, or as an expression vector that includes a promoter operatively linked to the specific sequence, or one designed to cause such a promoter to be introduced. The vector may exist in a state independent of the host cell chromosome, or may be integrated into the host cell chromosome
As used herein, the term “host cell” refers to cells that have been engineered to contain nucleic acid segments or altered segments, whether archeal, prokaryotic, or eukaryotic. Thus, engineered, or recombinant cells, are distinguishable from naturally occurring cells that do not contain recombinantly introduced genes through the hand of man.
A nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it effects the transcription of the sequence; or a ribosome binding site is operably linked to e coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” refers to a DNA sequences being linked are contiguous and, in the case of a secretory leader, contiguous and in same reading frame. Enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, then synthetic oligonucleotide adaptors or linkers are used in accord with conventional practice.
As used herein, the terms “cell” and “cell culture” are used interchangeably end all such designations include progeny. Thus, the words “transformants” and “transformed cells” include the primary subject cell and cultures derived therefrom without regard for the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. Mutant progeny that have the same function or biological activity as screened for in the originally transformed cell are included. Different designations are will be clear from the contextually clear.
As used herein, the term “plasmid” are designated by a lower case p preceded and/or followed by capital letters and/or numbers and refer to self-replicating circular DNA that include an origin of replication, and typically one or more selectable markers. The starting plasmids herein are commercially available, are publicly available on an unrestricted basis, or can be constructed from such available plasmids in accord with published procedures. In addition, other equivalent plasmids are known in the art and will be apparent to the ordinary artisan.
As used herein, the term “selectable marker” refers to the use of a gene that encodes an enzymatic activity and which confers the ability to grow in medium lacking what would otherwise be an essential nutrient (e.g., the HIS3 gene in yeast cells); in addition, a selectable marker may confer resistance to an antibiotic or drug upon the cell in which the selectable marker is expressed. A review of the use of selectable markers in mammalian cell lines is provided in Sambrook, J., et al., M
As used herein the terms “protein”, “polypeptide” or “peptide” refer to compounds comprising amino acids joined via peptide bonds and are used interchangeably.
As used herein, the terms “fusion protein” or “chimeric protein” refer to a hybrid protein, that includes portions of two or more different polypeptides, or fragments thereof, resulting from the expression of a polynucleotide that encodes at least a portion of each of the two polypeptides.
As used herein, the term “transformation,” refers to a process by which exogenous DNA enters and changes a recipient cell. It may occur under natural or artificial conditions using various methods well known in the art. Transformation may rely on any known method for the insertion of foreign nucleic acid sequences into a prokaryotic or eukaryotic host cell. The method is selected based on the host cell being transformed and may include, but is not limited to, viral infection, electroporation, lipofection, and particle bombardment. Such “transformed” cells include stably transformed cells in which the inserted DNA is capable of replication either as an autonomously replicating plasmid or as part of the host chromosome.
As used herein, the term “transfection” refers to the introduction of foreign DNA into eukaryotic cells. Transfection may be accomplished by a variety of methods known to the art including, e.g., calcium phosphate-DNA co-precipitation, DEAE-dextran-mediated transfection, polybrene-mediated transfection, electroporation, microinjection, liposome fusion, lipofection, protoplast fusion, retroviral infection, and biolistics. Thus, the term “stable transfection” or “stably transfected” refers to the introduction and integration of foreign DNA into the genome of the transfected cell. The term “stable transfectant” refers to a cell that has stably integrated foreign DNA into the genomic DNA. The term also encompasses cells that transiently express the inserted DNA or RNA for limited periods of time. Thus, the term “transient transfection” or “transiently transfected” refers to the introduction of foreign DNA into a cell where the foreign DNA fails to integrate into the genome of the transfected cell. The foreign DNA persists in the nucleus of the transfected cell for several days. During this time the foreign DNA is subject to the regulatory controls that govern the expression of endogenous genes in the chromosomes. As used herein, the term “transient transfectant” refers to cells that have taken up foreign DNA but have failed to integrate this DNA.
The present invention can be used to circumvent drawbacks in the prior art, in particular, stabilizing peptide binding to the MHC peptide binding groove. Previous efforts have revealed the ability to engineer and produce peptide/MHC molecules in bacteria by covalently joining the MHC class I peptide, β2 microglobulin, and heavy chain with discrete amino acid linkers (designated single-chain trimers [SCTs]) (Yu et al., 2002). For most SCTs reported, these engineered proteins fold correctly and specifically engage CD8+ T cells as tetramers (Mitaksov et al., 2007), irrespective of the artificial linker design (Hansen et al., 2009). However, this particular SCT method still utilizes a bacterial expression system and requires substantial purification and refolding efforts.
The present inventors have developed an alternative method to potentially improve the production of peptide/MHC based on the SCT approach. The present invention has the ability to rapidly generate eukaryotic cell lines that stably express and secrete peptide/MHC into the tissue media for purification and biotinylation. This novel protocol provides a much faster/convenient route to generating properly folded peptide/MHC with minimal user intervention, especially for MHC class I targets with high demand (such as the model OVA epitope SIINFEKL). By using a SCT strategy, it was possible to generate MHC molecules presenting a range of class I peptides (i.e., low-to-high binding affinity), which can be reliably generated. Additionally, these eukaryotic-derived peptide/MHC molecules can be used to recapitulate binding dynamics with TCRs in downstream assays (Schmidt and Lill 2018).
Mice. Female 6-8-week-old C57BL/6J (stock #000664) and OT-1 (stock #003831) mice were purchased from The Jackson Laboratory (Bar Harbor, Me., USA) and maintained in micro-isolator cages under sterile conditions. Animals were humanely euthanized and spleens/lymph nodes harvested and combined for Ficoll gradient centrifugation (GE HealthCare, Piscataway, N.J.). The lymphocyte interphase was then subjected to ACK lysis and eventual CD8+ T cell purification using MACS bead positive selection as instructed by the manufacturer (Miltenyi Biotec, Cambridge, Mass.). Purified CD8+ T cells were aliquoted in 90% FBS/10% DMSO and stored in liquid nitrogen until use. All mouse procedures were followed in accordance with TTUHSC IACUC-approved protocols.
Cell lines and culture. FreeStyle™ Chinese Hamster Ovary (CHO-S) (Thermo Fisher Scientific, Waltham, Mass.) and 4T1 (ATCC, Manassas, Va.) cells were utilized for in vitro studies. CHO-S cells were passaged in FreeStyle™ CHO Expression Medium (Thermo Fisher Scientific) according to the manufacturer's recommendations. 4T1 cells are naturally deficient in H-2 Kb expression and were grown in RPMI 1640 supplemented with 10% heat-inactivated FBS, 100 U/ml penicillin, 100 μg/ml streptomycin, and 10 mmol/l L-glutamine (all from Thermo Fisher Scientific). All cell lines were maintained in vented flasks at 37° C. with 5% CO2.
Cloning strategy and construction of transposon expression vectors. Full-length mouse p2 microglobulin (NCBI Reference Sequence: NM 009735.3) and MHC class I heavy chain (H-2 Kb) (NCBI Reference Sequence: NM_001001892.2), relevant sequences incorporated herein by reference, cDNA were synthesized from C57BL/6J splenocytes following TRIzol lysis (Thermo Fisher Scientific) and RT-PCR using oligo(dT) primers (SuperScript IV First-Strand Synthesis Kit; Thermo Fisher Scientific). Secretory MHC class I heavy chain was designed to not include the transmembrane domain. The leader signal, SIINFEKL epitope, and Gly/Ser amino acid linkers were ultimately added by overhang PCR as previously reported (Hansen et al., 2009) using the Phusion High-Fidelity DNA Polymerase (Thermo Scientific Fisher). PCR fragments were gel excised/purified and ligated (LigaFast™ Rapid DNA Ligation System; Promega, Madison, Wis.) into puc19 (NEB, Ipswich, Mass.) via SacI/HindIII restriction enzyme sites and fragments pieced together using the unique NheI/BamHI sites of the synthetic peptide/MHC sequence. The BirA AviTag™ amino acid sequence (GLNDIFEAQKIEWHE SEQ ID NO: 600) was subsequently added to the construct's terminus by overlap-extension PCR and cloned into a separate puc19 holding vector. Full-length peptide/MHC was then amplified and cloned into the pSBbi-pur transposon vector (kindly provided by Dr. Eric Kowarz [Addgene plasmid #60523]) using the SfI restriction enzyme sites (Kowarz et al., 2015). Plasmid transformations were carried out in chemically-competent NEB-5 alpha E. coli (NEB) using ampicillin selection. All vector constructs were confirmed by restriction enzyme digestion and DNA sequencing.
Sleeping Beauty (SB) transposon system. Parental cell lines were transiently transfected with transposon-related vectors using Lipofectamine reagent (Thermo Fisher Scientific) as directed by the manufacturer. A plasmid encoding the SB 100× transposase (pCMV[CAT]T7-SB100; designated Vector 1), a gift from Dr. Zsuzsanna Izsvak (Addgene plasmid #34879), and a transposon plasmid containing the necessary inverted terminal repeats (pSBbi-pur; designated Vector 2) were used. Both vectors were provided concurrently to stably integrate peptide/MHC transgenes into cells. Briefly, 1×105 cells were plated in 24-well plates (Corning, Corning N.Y.) and exposed to Vector 1 (12.5 ng)/Vector 2 (488 ng) in a total volume of 500 μl media as similarly described (Kowarz et al., 2015). Culture media was replenished with 2 ml fresh media after 24 hrs and 48 hrs, whereupon cells were exposed to lethal doses of puromycin (CHO-S—10 μg/ml; 4T1—5 μg/ml) (Invivogen, San Diego, Calif.). Fresh media containing puromycin was provided every 2-3 days as needed. Generally, actively dividing cells were ready for expansion by 2 weeks, with virtually all cell clones expressing peptide/MHC molecules.
SDS-PAGE and western blot. To remove extraneous tissue media components such as surfactants, CHO cell supernatants were passed onto PD10 columns (GE Healthcare) and concentrated/washed in PBS using a 30 MWCO Amicon centrifugal unit (MilliporeSigma, Burlington, Mass.). Protein concentration was determined using a BCA protein assay kit (Thermo Scientific Fisher) and sample aliquots stored at −80° C. until use. Protein purity was assessed with SDS-PAGE and coomassie blue staining while protein identity was confirmed through western blotting. Briefly, proteins were resolved on a 4%/12% polyacrylamide gel, transferred to a PVDF membrane (Amersham Hybond, 0.2 μm; GE Healthcare), and blocked with 5% milk in PBST (0.1% Tween 20 in PBS) for 1 hr at RT. Membranes were then incubated with various primary antibodies (1 μg/ml) in block solution with rocking at 4° C. overnight. Specific primary reagents included anti-mouse β2 microglobulin (clone 893803; R&D Systems, Minneapolis, Minn.) or anti-BirA tail (clone Abc; Avidity, Aurora, Colo.) antibodies. Blots were then washed extensively with PBST and incubated in block with secondary HRP-conjugated goat antibodies specific to rat IgG (H+L) or mouse IgG (H+L) (Thermo Scientific Fisher) for 1 hr at RT. Washed blots were finally developed with a SignalFire ECL reagent (Cell Signaling, Danvers, Mass.) and exposed/imaged on a ChemiDoc™ Touch Imaging System (Bio-Rad, Hercules, Calif.). In separate experiments, blots containing biotinylated protein were probed with a Streptavidin-HRP reagent (Thermo Scientific Fisher) for 1 hr at RT to confirm streptavidin binding potential.
Immunoprecipitation. A Pierce Classic IP kit (Thermo Scientific Fisher) was used to investigate ligand binding of soluble peptide/MHC protein. Peptide/MHC protein was incubated overnight at 4° C. with 2 μg of the anti-SIINFEKL (clone eBio25-D1.16; Thermo Scientific Fisher) or mouse IgG isotype (clone MOPC-21; MP Biomedicals, Santa Ana, Calif.) antibodies. The anti-SIINFEKL antibody functions as a TCR-like antibody (Lowe et al., 2017), and binds SIINFEKL/H-2 Kb much like SIINFEKL-reactive T cells such as OT-1 CD8+ T cells. Following purification of IgG containing complexes, samples were boiled and analyzed by western blot as described above.
Affinity chromatography (AC). The MHC class I-reactive M1/42 antibody (Bio X Cell, West Lebanon, N.H.) was covalently bound to an NHS-activated agarose bead column (HiTrap™ NHS-activated HP; GE Healthcare) manually as directed by the manufacturer. The column was attached to an ÄKTA™ start chromatography system (GE Healthcare) for automatic operation and equilibrated with 20 mM sodium phosphate, pH 7.0 (binding buffer). Cell-free supernatants were first desalted in PBS using PD-10 columns and diluted 1:2 in binding buffer prior to AC. Samples were then applied to the M1/42 column, unbound material washed away with binding buffer, and peptide/MHC molecules eluted using 0.1 M glycine, pH 2.7. Eluates were dispensed in tubes containing 1 M Tris, pH 9 and relevant fractions combined and concentrated/washed in PBS as explained above.
Biotinylation and tetramerization. Peptide/MHC was biotinylated using 2.5 μg BirA ligase (Avidity) overnight at 4° C. according to the manufacturer's guidelines. Reaction components were removed by successive washes in PBS using a 30 MWCO centrifugal filter (MilliporeSigma). Alternatively, larger reaction mixtures could be exclusively polished through size exclusion chromatography (Altman and Davis 2016) using a HiPrep™ 16/60 Sephacryl™ S-200 HR column (GE Healthcare) as indicated in
Enzyme-Linked Immunosorbent Assay (ELISA). To investigate the success of peptide/MHC biotinylation, a 96-well high protein binding plate (Corning) was first coated overnight at 4° C. with 4 μg/ml streptavidin (Promega) in 0.1 M sodium carbonate and then blocked (3% BSA/PBS) for 1 hr at RT. Biotinylated protein samples were diluted in block and added to wells at various dilutions and incubated at RT for 1 hr. Wells were washed extensively with PBST and then exposed to 4 μg/ml of either a MHC class I-reactive (clone M1/42; Biolegend) or rat isotype control IgG (Biolegend) antibody in block. In separate wells, a positive control biotinylated irrelevant rat antibody (Biolegend) was incorporated to validate the extent of streptavidin binding. The plate was again washed with PBST and relevant wells provided a goat anti-rat HRP (Thermo Scientific Fisher) or goat anti-mouse FcγR-specific HRP (Jackson ImmunoResearch, West Grove, Pa.) antibody in block for 1 hr at RT. Wells were washed with PBST and developed for 5 min after the addition of 200 μl 1-Step Ultra TMB (Thermo Scientific Fisher). Reactions were terminated with 100 μl TMB stop solution (KPL), and the absorbance immediately read at 450 nm using a Cytation 5 Imaging Reader (Biotek, Winooski, Vt.).
Flow cytometry. To confirm gene expression, the 4T1 cell line (1×105 cells) was stained with relevant primary antibodies (anti-SIINFEKL/H-2 Kb or mouse IgG isotype antibodies at 2 μg/ml) in FACS buffer (0.5% BSA/0.1% NaN3 in PBS) for 20 min at 4° C., washed, incubated with a PE-conjugated anti-mouse secondary antibody (Jackson ImmunoResearch), washed again, and resuspended in FACS buffer for analysis (
Cloning, expression, and purification strategy for soluble eukaryotic-derived peptide/MHC. The design of linked peptide/MHC class I molecules closely followed the previously reported generation of SCTs in bacteria (Hansen et al., 2009). Essentially, as presented in
Purification of secreted and fully-folded peptide/MHC protein. The suitability of the SB transposon system to stably integrate the peptide/MHC transgene was first determined. However, this particular peptide/MHC construct differed from the aforementioned soluble design in
CHO cells were next transfected with SB-related vectors as described in
Determination of peptide/MHC identity and upstream binding potential. Next, the inventors confirmed the identity of AC purified protein by western blot separate from MHC class I reactivity. Based on the linked design of polychain peptide/MHC molecules (
Multimerization and functional assessment of eukaryotic-derived peptide/MHC. Biotinylated peptide/MHC arguably provides the greatest convenience to users for downstream assays. The inventors, therefore, designed a BirA tail to the terminal end of the peptide/MHC transgene by using a particular BirA tail peptide, GLNDIFEAQKIEWHE (SEQ ID NO: 600), which offers a highly targeted site for enzymatic conjugation of biotin with minimal footprint (Beckett et al., 1999). AC purified peptide/MHC was subjected to BirA ligase activity in the presence of free biotin overnight. Excess biotin and other reaction components were removed by excessive washing in PBS using a 30 MWCO centrifugal unit, and the extent of biotinylation first assessed by western blot and ELISA. In the case of western blot analysis, SDS-PAGE-resolved biotinylated protein was incubated with HRP-conjugated streptavidin to generate a specific peptide/MHC signal (
Next, the inventors assessed the ability of fluorescently-labeled multimers to specifically detect antigen-specific CD8+ T cells. Splenocytes and lymph nodes were harvested from wild-type and OT-1 transgenic (i.e., SIINFEKL-reactive) mice and CD8+ T cells subsequently purified through magnetic bead selection. Biotinylated SIINFEKL/H-2 Kb was then incubated with PE-conjugated streptavidin following a 4:1 molar ratio, thereby, generating tetramers. In order to stabilize membrane dynamics of TCRs, CD8+ T cells were exposed to dasatinib (as previously described [Dolton et al., 2015]), followed by incubation with tetramers. After suitable wash steps, cells were specifically labeled with a FITC-conjugated anti-mouse CD8 antibody that displays minimal interference with TCR:MHC binding (Clement et al., 2011). Cells were fixed and double-positive events (CD8+/tetramer+) assessed by flow cytometry. As detailed in
Although MHC class I peptide candidates can be easily identified through in silico prediction methods (Andreatta and Nielsen 2016), free peptide occupancy of MHC class I molecules tends to be a rate limiting step in successfully generating stable peptide/MHC molecules from bacteria (Altman and Davis 2016). Considering the vital role MHC plays in human health (Cho and Sprent 2018), an inability to produce certain peptide/MHC reagents may adversely impact efforts on a number of fronts including diagnostics, therapies, and generalized scientific endeavors. For example, the burgeoning field of neoepitope identification for personalized cancer therapy could be stalled by those unique patient epitopes that exhibit high dissociation rates from MHC class I (Hu et al., 2018). One workaround to the issue of peptide occupancy has been in designing and expressing polychain SCTs that ensure full assembly of peptide, p2 microglobulin, and MHC class I heavy chain through flexible linkers (Hansen et al., 2009). SCTs retained on the plasma membrane of eukaryotic cells maintain their native conformation and are highly resistant to exogenous peptide binding (Yu et al., 2002). Additionally, membrane-bound SCTs serve as effective targets for CD8+ T cell priming (Hung et al., 2007) and destruction (Yu et al., 2002). In the case of diagnostic determination of CD8+ T cell frequencies by tetramers, SCTs can be modified for expression/secretion in bacteria and biotinylation by way of an explicit amino acid sequence that directs BirA enzyme function (Mitaksov et al., 2007).
Previously, the present inventors developed a unique protocol to establish eukaryotic cell lines (such as CHO suspension cells) in as little as two weeks that stably secrete peptide/MHC molecules through transposon-directed delivery. Soluble peptide/MHC may then be biotinylated and utilized as multimers (via streptavidin), particularly for CD8+ T cell relevant assays. Currently, CHO cells are an industry standard in producing FDA approved therapeutic recombinant proteins (Kuo et al., 2018). The inventors sought the advantages of the CHO cell line in order to [i] instigate post-translational modifications and [ii] be easily grown at high density under serum-free conditions in suspension cultures. However, other common cell line “protein workhorses” (e.g., HEK-293 cells) are amenable to the expression and characterization techniques outlined.
One advantage of the present invention is the rapid development of stable CHO cells secreting peptide/MHC using the SB transposon system. These studies incorporated the SB transposase SB100X, which has a high gene insertion efficiency at close-to-random chromosomal sites (Mates et al., 2009). The SB approach provides the advantageous properties of viral transduction to insert transgenes without the disadvantages of either maintaining genomic material episomally (e.g., adeno-associated viruses) or near/in proto-oncogenes (e.g., retroviral vectors) (Kebriaei et al., 2017). Additionally, manufacturing high-quality viral particles can be a cumbersome task fraught with regulatory obstacles. The inventors generally experienced minimal difficulty in developing and expanding stable lines from parental cells after transiently transfecting plasmids that propagated the SB transposon system. The protocol is also amenable to freezing material at convenient stopping points. There was no apparent adverse effects to generating multimerized reagents when either cell-free CHO-derived supernatants or biotinylated peptide/MHC was frozen long-term at −80° C. The method of the present invention is compatible with downstream tetramer production with the added benefits of convenient peptide/MHC expression that can incorporate a range of peptide affinities to the MHC peptide binding groove. Traditionally, to circumvent the low intrinsic affinity of the TCR with peptide/IIC, tetravalent multimers have been utilized to increase T cell avidity. However, these soluble peptide/MHC molecules can be utilized for higher order reagents to better discriminate low frequency T cells (or bind “difficult” TCRs) such as fluorochrome-conjugated dextramers since the production process involves incubating biotinylated peptide/MHC with a dextran backbone containing streptavidin (Dolton et al., 2014). Thus, the present invention can be used to reliably produce a range of soluble eukaryotic-derived peptide/MHC molecules for diagnostic, therapeutic, and investigative purposes.
It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method, kit, reagent, or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.
It will be understood that particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of the invention. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.
All publications and patent applications mentioned in the specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” Throughout this application, the term “about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.
As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. In embodiments of any of the compositions and methods provided herein, “comprising” may be replaced with “consisting essentially of” or “consisting of”. As used herein, the phrase “consisting essentially of” requires the specified integer(s) or steps as well as those that do not materially affect the character or function of the claimed invention. As used herein, the term “consisting” is used to indicate the presence of the recited integer (e.g., a feature, an element, a characteristic, a property, a method/process step or a limitation) or group of integers (e.g., feature(s), element(s), characteristic(s), property(ies), method/process steps or limitation(s)) only.
The term “or combinations thereof” as used herein refers to all permutations and combinations of the listed items preceding the term. For example, “A, B, C, or combinations thereof” is intended to include at least one of: A, B, C, AB, AC, BC, or ABC, and if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.
As used herein, words of approximation such as, without limitation, “about”, “substantial” or “substantially” refers to a condition that when so modified is understood to not necessarily be absolute or perfect but would be considered close enough to those of ordinary skill in the art to warrant designating the condition as being present. The extent to which the description may vary will depend on how great a change can be instituted and still have one of ordinary skill in the art recognize the modified feature as still having the required characteristics and capabilities of the unmodified feature. In general, but subject to the preceding discussion, a numerical value herein that is modified by a word of approximation such as “about” may vary from the stated value by at least 1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.
All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.
To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims to invoke paragraph 6 of 35 U.S.C. § 112, U.S.C. § 112 paragraph (f), or equivalent, as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.
For each of the claims, each dependent claim can depend both from the independent claim and from each of the prior dependent claims for each and every claim so long as the prior claim provides a proper antecedent basis for a claim term or element.
This application claims priority to U.S. Provisional Application Ser. No. 62/746,198, filed Oct. 16, 2018, the entire contents of which are incorporated herein by reference.
This invention was made with government support under R15 CA215874 and W81XWH-18-1-0293 awarded by the National Institutes of Health and the Department of Defense, respectively. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/056281 | 10/15/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62746198 | Oct 2018 | US |
