Patent Application
20080019948
The process according to the present invention for preparing cells for cell therapy comprises the steps of inducing Th cells having a nonspecific antitumor activity; and imparting antigen specificity to the Th cells.
The Th cells having a nonspecific antitumor activity can be induced as described below. Mononuclear cells are isolated from human peripheral blood by, for example, specific gravity centrifugation, and are cultured in a medium (AIM-V (Invitrogen), human AB blood serum or serum that is the same blood type as the cultured cells and preferably autologous serum at 0.1 to 30%, preferably at 5 to 10%) in the presence of anti-CD3 antibody and IL-2. The final concentration of IL-2 is 10 to 2000 IU/mL, and preferably 50 to 500 IU/mL. Antigen-nonspecifically activated Th cells can be induced in this manner.
In another embodiment, the process according to the present invention for preparing cells for cell therapy comprises the steps of inducing Th1 and Tc1 cells having a nonspecific antitumor activity; and imparting antigen specificity to these Th1 cells and Tc1 cells.
The Th1 cells and Tc1 cells having a nonspecific antitumor activity can be induced as follows. Mononuclear cells are isolated from human peripheral blood by, for example, specific gravity centrifugation, and are cultured in a medium (AIM-V (Invitrogen), with human blood serum: AB blood serum or serum that is the same blood type as the cultured cells, and preferably autologous serum, at 0.1 to 30%, preferably at 5 to 10%) in the presence of anti-CD3 antibody, IL-2, and IL-12, preferably in the presence of anti-CD3 antibody, IL-2, IL-12, and anti-IL-4 antibody, and more preferably in the presence of anti-CD3 antibody, IL-2, IL-12, anti-IL-4 antibody, and IFN-γ. The preferred concentration of each cytokine, in a final concentrations of 10 to 2000 IU/mL and preferably 50 to 500 IU/mL of IL-2, 1 to 1000 IU/mL and preferably 10 to 200 IU/mL of IL-12, 1 to 500 ng/mL and preferably 5 to 100 ng/mL of IFN-γ, and 0.1 to 100 μg/mL and preferably 0.5 to 10 μg/mL of anti-IL-4 antibody. Antigen-nonspecifically activated Th1 cells and Tc1 cells can be induced in this manner.
Next, antigen specificity for tumor cells is imparted to the Th cells or Th1 cells and Tc1 cells obtained as described above which have a nonspecific antitumor activity. The step of imparting antigen specificity to the Th cells or Th1 cells and Tc1 cells is carried out by transducing a gene for a TCR that recognizes a cancer-associated antigen to allow for expression of the TCR on the surface of those Th cells or Th1 cells or Tc1 cells. The TCR may be a class I-restricted TCR or a class II-restricted TCR.
The TCR gene can be isolated from a tumor-specific human CTL clone. The tumor-specific CTL clone may be cloned by limit dilution of isolated human T cells or may be induced by in vitro cultivation of isolated human CTLs in the presence of an antigen. TCR gene may be readily cloned by the 5′ RACE procedure using primers corresponding to the sequences specific to the TCR α-chain gene and the TCR β-chain gene.
The TCR gene can be transduced into the T cells using any of various viral vectors. Such vectors may include, for example, lentivirus vectors, retrovirus vectors, adenovirus vectors, adeno-associated virus vectors, Sendai virus vectors, and liposomes. The vector comprises, inter alia, a promoter region, initiation codon, stop codon, and terminator region, which are arranged in an order that enables expression of the TCR gene in the T cells. The viral vector incorporating the TCR gene can be transduced into the antigen-nonspecifically activated T cells utilizing, for example, a suitable packaging plasmid or helper plasmid. Proceeding in this manner provides Th cells or Th1 cells and Tc1 cells to which specificity for tumor cells has been imparted.
In a preferred embodiment of the present invention, a TCR gene from a tumor-specific CTL may be transduced into MHC class II-restricted Th cells as the antigen-nonspecifically activated T cells to obtain Th cells that can directly bind to tumor cells through the expression of a class I-restricted TCR. Such a Th cell is very useful for application in the treatment of cancer, because it has both an antitumor activity and a helper activity. The Th cells are particularly preferably Th1 cells.
In addition, Th cells to which antigen specificity has been imparted may be purified from the activated T cell population obtained as described above. This process can be carried out by isolating antigen-specific CD4 positive cells using magnetic beads bearing anti-CD4 antibody.
Th1 cells and Tc1 cells to which antigen specificity has been imparted may also be separated from the activated T cell population obtained as described above. This process can be carried out by isolating antigen-specific CD4 positive cells or antigen-specific CD8 positive cells using magnetic beads bearing anti-CD4 antibody or anti-CD8 antibody. The Th1 cells and Tc1 cells isolated in this manner can be mixed in any proportion so as to obtain an optimal effect in cancer treatment.
The Th cells or Th1 cells and Tc1 cells having antigen specificity obtained by the process according to the present invention can be evaluated for their antigen specificity as follows. Human peripheral blood mononuclear cells of known HLA are transformed with EB virus to obtain a lymphoblastoid cell line (LCL). The cells are peptide-pulsed by adding to the culture medium a corresponding HLA-restricted peptide derived from the target antigen. This process yields LCL cells in which the corresponding HLA/peptide antigen complex is expressed on the cell surface. The Th cells or Th1 cells or Tc1 cells having antigen specificity obtained by the process according to the present invention are then co-cultured with mitomycin C-inactivated, peptide-pulsed LCL cells or with non-peptide-pulsed LCL cells as a control. The antigen specificity can then be determined by measuring and comparing the amount of IFN-γ or IL-2 in the culture supernatants.
The Th cells or Th1 cells or Tc1 cells having antigen specificity obtained by the process according to the present invention can be evaluated for their antitumor activity by bringing the T cells into contact with 51Cr-labeled, peptide-pulsed LCL cells for a predetermined period of time, and measuring the amount of 51Cr released from the cells.
The content of all patents and reference documents expressly cited in the specification of this application are hereby incorporated by reference in its entirety. In addition, the content of the specification and drawings of Japanese Patent Application 2003-425009, which is the basis for the priority claim of this application, are hereby incorporated by reference in its entirety.
The present invention is described in greater detail by the examples provided below, but these examples are not intended to limit the scope of the present invention.
The TCR α-chain gene and TCR β-chain gene were isolated by the 5′ RACE procedure from TAK-1, a CTL clone derived from an HLA-A24 positive healthy donor and specific for tumors having the WT1 tumor antigen, and then the sequence of the genes was determined.
The WT1-specific TCR α-chain gene and TCR β-chain gene originating from the CTL of an HLA-A24 positive healthy donor were incorporated into the lentivirus-vector CSII and introduced into E. coli strain DH10B. The amplified vector was purified by a CaCl2 centrifugation method.
The CSII lentivirus vector incorporating the WT1-specific TCR α-chain gene and TCR β-chain gene originating from the CTL of an HLA-A24 positive healthy donor was added to a culture of 293T cells along with the packaging plasmid pMDLg/pRRE, the Rev expression plasmid pRVS-Rev, and the VSV-G plasmid pMD.G, and continued incubation. After treatment with forskolin, a culture supernatant was collected that contained large amounts of lentivirus vector incorporating the TCR α-chain gene and TCR β-chain gene.
Anti-CD3 antibody-coated plates were prepared in advance by immobilizing anti-CD3 antibody on culture plates. Mononuclear cells isolated from peripheral blood by specific gravity centrifugation method were cultured under type 1 culture conditions in the presence of 100 IU/mL of IL-2, 50 IU/mL of IL-12, 10 ng/mL of IFN-γ, and 2 μg/mL of anti-IL-4 antibody (type 1 cytokines).
The lentivirus vector-containing culture supernatant obtained in Example 1 and type 1 cytokines were added to mononuclear cells that had been cultured for 2 days under type 1 culture conditions and cultivation was continued. After 24 hours, the lentivirus vector-containing culture supernatant and type 1 cytokines were added again and cultivation was continued, whereby the WT1-specific TCR α-chain gene and TCR β-chain gene originating from the CTL of an HLA-A24 positive healthy donor were transduced into non-specifically activated T cells.
The activated T cells transduced with the WT1-specific TCR α-chain gene and TCR β-chain gene originating from the CTL of an HLA-A24 positive healthy donor was expanded for additional 10 days.
From the T cells which had been nonspecifically activated under type 1 culture conditions and transduced with the WT1-specific TCR α-chain gene and TCR β-chain gene originating from the CTL of an HLA-A24 positive healthy donor, CD4 positive T cells (Th1 cells) and CD8 positive T cells (Tc1 cells) were isolated using commercially available MACS MicroBeads CD4 and MACS MicroBeads CD8 (Miltenyi Biotec), respectively.
HLA-A24 is the most frequently occurring human MHC class I antigen in the Japanese population. An HLA-A24 positive lymphoblastoid cell line (LCL) obtained by EB viral transformation of peripheral blood mononuclear cells from an HLA-A24 positive healthy donor were used for the hypothetical tumor cell population. HLA-A24-restricted peptide from WT1 protein was added at a concentration of 10 μg/mL for 16 hours (peptide-pulse), then unreacted peptide was washed off. This procedure yields LCL cells expressing an HLA-A24/WT1 peptide complex on the cell surface.
The Th1 cells (WT1-A24TCR+Th1 cells) or Tc1 cells (WT1-A24TCR+Tc1 cells) purified in Example 3 were co-cultured for 24 hours with either the WT1 peptide-pulsed LCL cells or nonpulsed LCL cells, both of which had been inactivated by treatment with mitomycin C. Then the level of IFN-γ and IL-2 in the culture supernatant was measured.
IFN-γ production was observed for both WT1-A24TCR+Th1 cells and WT1-A24TCR+Tc1 cells co-cultured with WT1 peptide-pulsed LCL cells, but not for those co-cultured with non-peptide-pulsed LCL cells (
IL-2 production was observed for the WT1-A24TCR+Th1 cells and WT1-A24TCR+Tc1 cells co-cultured with WT1 peptide-pulsed LCL cells, but the production level of the WT1-A24TCR+Tc1 cells was lower than the Th1 cells. IL-2 production was not detected for either the WT1-A24TCR+Th1 cells or the WT1-A24TCR+Tc1 cells co-cultured with non-peptide-pulsed LCL cells (
With regard to the control Th1 cells and control Tc1 cells, which were comparative controls that were not transduced with the WT1-specific TCR gene, the production of IFN-γ or IL-2 was not detected when co-cultured with WT1 peptide-pulsed LCL cells (
The cytotoxicity of the purified WT1-A24TCR+Th1 cells or WT1-A24TCR+Tc1 cells was measured in a 4-hour 51Cr release assay using 51Cr-labeled, WT1 peptide-pulsed LCL cells as the target cells. The cytotoxicity of control Th1 cells and control Tc1 cells, which were not transduced with the WT1-specific TCR gene, was also measured as a comparative control.
The WT1-A24TCR+Th1 cells exhibited cytotoxicity, while the control Th1 cells exhibit no cytotoxicity. In addition, the WT1-A24TCR+Tc1 cells exhibited a much stronger cytotoxicity than did the WT1-A24TCR+Th1 cells, while cytotoxicity was not shown in the control Tc1 cells (
These results demonstrated that the Tc1 cells having a nonspecific antitumor activity can be genetically engineered by transducing a tumor-specific TCR gene to obtain cells capable of specifically damaging tumor cells. In addition, it was shown that nonspecifically activated MHC class II-restricted Th1 cells can be genetically engineered by transducing a TCR gene obtained from an MHC class I-restricted antigen-specific CTL to obtain cells capable of reacting with an MHC class I molecule/peptide antigen complex and having both helper activity and antitumor activity.
The activated T cell medicine according to the present invention can specifically damage tumor cells and thus is useful in the treatment of cancer.
upper line in x-axis label, left to right:
upper line in x-axis label, left to right:
y-axis: cytotoxicity (%)
x-axis: effector cell/target cell ratio
- x - label: control Tc1
- •- label: control Th1
1.
Perhaps the “Mosmsnn” appearing on page 2, line 5 of the Japanese original, should be spelled “Mosmann”?
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-425009 | Dec 2003 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP04/19714 | 12/22/2004 | WO | 00 | 5/21/2007 |
