METHODS OF MODULATING FUCOSYLATION OF GLYCOPROTEINS

Description

FIELD OF THE INVENTION

The invention relates to glycoproteins and glycoprotein preparations having reduced core fucosylation and methods related thereto, e.g., methods of making and using the glycoproteins and glycoprotein preparations.

BACKGROUND OF INVENTION

A typical glycoprotein consists not only of an amino acid backbone but also includes one or more glycan moieties. The glycan moieties attached to the amino acid backbone of a glycoprotein can vary structurally in many ways including, sequence, branching, sugar content, and heterogeneity. Glycosylation adds not only to the structural complexity of the molecules, but also affects or conditions many of a glycoprotein's biological and clinical attributes.

SUMMARY OF INVENTION

As is disclosed herein, the relationship between GDP-fucose levels in a cell and the level of fucosylation of proteins produced by a cell is not linear. A relatively modest reduction in GDP-fucose levels in the cell can result in a much lower level of fucosylation on proteins produced by the cell. Thus, when levels of GDP-fucose taught herein are used, the reduction of fucose on proteins produced by the cells can be maximized with minimal reduction in GDP-fucose levels and minimal disruption of other aspects of metabolism. E.g., one or more manipulations described herein can be used to achieve a minimal reduction of GDP-fucose levels but still provide a relatively great reduction in fucosylation. Thus, methods described herein allow optimization of the levels of GDP-fucose reduction with reduction in the fucosylation of proteins made by the cell.

The inventors have shown that the relationship between the level of GDP-fucose in a cell and the level of fucosylation on proteins made by the cell is non-linear. In embodiments the curve which describes the relationship between level of GDP-fucose in a cell and level of fucosylation of proteins made by the cell includes three phases. In embodiments the three phase are as follows: a first phase, beginning at relatively high concentrations of GDP-fucose, and continuing through declining levels of GDP-fucose, wherein the level of fucosylation on proteins made by the cell is, compared to the other two phases, relatively constant; a second phase, beginning at levels of GDP-fucose that are lower than the levels seen in the first phase, wherein the level of fucosylation on proteins made by the cell, compared to the other two phases, drops rapidly in response to a decrease in GDP-fucose level; and a third phase, beginning at levels of GDP-fucose that are lower than levels in the second phase, and continuing through declining levels of GDP-fucose, wherein the level of fucosylation on proteins made by the cell is, compared to the other two phases, relatively constant.

In embodiments the curve which describes the relationship between level of GDP-fucose in a cell and level of fucosylation of proteins made by the cell has three phases: a phase having a high relatively constant (relatively independent of the amount of GDP-fucose) level of fucosylation (points to the left of point A in FIG. 1), a phase of rapid decrease in fucosylation (points between A and B in FIG. 1, wherein the level of fucosylation is relatively sensitive to the amount of GDP-fucose), and phase having a lower, relatively constant, level of fucosylation (relatively independent of the amount of GDP-fucose) (points to the right of point B in FIG. 1). (FIG. 1 and the contents therein are typical. Of course analogous plots may also be used. In embodiments the curve plotting the relationship between level of GDP-fucose in a cell and level of fucosylation of proteins made by the cell may look different from that in FIG. 1, but it will still have the three phases described.)

The appreciation of this relationship can be used to guide selection of the level of GDP-fucose, e.g., to allow minimization of the level of fucosylation with minimal reduction in the level of GDP-fucose in the cell. The balance between low fucose and undesirable contributions of low GDP-fucose levels can be optimized. This can allow minimizing the negative effects of very low concentrations of GDP-fucose.

For example, in some embodiments a decrease in GDP-mannose concentrations can be an undesirable side effect of very low GDP-fucose levels. In some instances a loss of GDP-fucose can lead to higher levels of conversion of GDP-mannose to GDP-fucose, leading to an undesirable decrease in intracellular levels of GDP-mannose. A decrease in GDP-mannose can result in a decrease in high mannose structures on proteins produced by the cell. High mannose structures mediate effector function, and particularly ADCC activity, of an antibody. Thus, if ADCC activity is a desirable property, a decrease in high mannose structures can be undesirable. Alternatively, if less ADCC activity is desired decreased GDP-mannose can be desirable.

Optimal levels can be determined by monitoring the levels of GDP-mannose in the cell; as needed the levels of GDP-fucose can be elevated if the levels of GDP-mannose begin to drop. In particular embodiments, GDP-fucose is increased, e.g., added, if GDP-mannose levels are less than about 90%, 80%, 70%, 60%, 50%, 40%, 30%, 25%, 20%, 15% or 10% of a reference GDP-mannose level, e.g., the level seen in an otherwise similar cell that does not have a reduction in GDP-mannose.

In other embodiments an increase in GDP-mannose concentrations is can be an undesirable side effect of very low GDP-fucose levels. In some instances a loss of GDP-fucose may lead to decreased conversion of GDP-mannose to GDP-fucose, leading to an undesirable increase in the levels of GDP-mannose (in some embodiments this might be observed when a cell is largely or completely deficient in the enzymes involved in the conversion of GDP-mannose to GDP-fucose). Optimal levels can be determined by monitoring the levels of GDP-mannose in the cell; as needed the levels of GDP-fucose or the level of the converting enzyme responsible for the GDP-fucose can be elevated if the levels of GDP-mannose begin to rise. In particular embodiments, GDP-fucose or the level of the converting enzyme is increased if GDP-mannose levels are more than about 2×, 3×, 4×, 5×, 6×, 7×, 8×, 9×, or 10× of a reference GDP-mannose level, e.g. the level seen in an otherwise similar cell that does not have reduction ion the GDP-mannose.

The invention features glycoproteins, e.g., antibodies, and preparations thereof having reduced fucosylation, e.g., reduced core fucosylation. Exemplary proteins include a peptide which comprises a human IgG constant region, e.g., one made in cultured cells, e.g., CHO cells, and having a glycan component attached in the CH2 region, e.g., at residue Asn 297. Preparations, e.g., pharmaceutically acceptable preparations, of these, and other proteins having reduced levels of fucosylation, e.g., core fucosylation, are provided. The presence of core fucosylation on an antibody significantly attenuates its ADCC activity. Reduction of core fucosylation increases ADCC activity.

The invention provides methods in which cells having a manipulation (defined below) can be used to provide proteins having reduced fucosylation. E.g, one or both of a genetically engineered alteration and culture conditions can be used to provide an optimized level of GDP-fucose and an optimized level of fucosylation on proteins made by a cell.

Accordingly, in one aspect, the invention features, a method of reducing fucosylation of a glycoprotein (or a preparation of glycoproteins). The method comprises:

providing a cell having or subject to a manipulation that results in a level of GDP-fucose in said cell that is below a first preselected level and, in embodiments, above a second preselected level and optionally memorializing one or both levels;

culturing said cell, e.g., to provide a batch of cultured cells;

optionally, measuring the level of GDP-fucose in said cell or batch of cultured cells;

optionally, separating the glycoprotein from at least one component with which said cell or batch of cultured cells was cultured; and

optionally, evaluating the glycoprotein (or a glycoprotein on the surface of the cell) for a parameter related to fucosylation;

thereby providing a glycoprotein with reduced fucosylation, e.g., wherein the level of fucosylation is reduced by a predetermined level in comparison with a reference.

In an embodiment the manipulation is or was selected on the basis of providing a level of GDP fucose below a first preselected level and optionally above a second preselected level.

In one embodiment, the method further comprises evaluating a glycan on the surface of said cell or batch of cultured cells in order to determine if the glycoprotein produced by said cell or batch of cultured cells has reduced fucosylation. In another embodiment, said evaluation comprises evaluating a glycan on the surface of said cell or batch of cultured cells, to determine a property of said glycan, comparing the property to a reference, to thereby determine if said glycan structure is present on the product.

In one embodiment, said first preselected level of GDP-fucose is selected from a level that is:

i.a) approximately equal to or less than 80%, 70% or 60% of a reference level, e.g., the level in said cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation;

ii.a) approximately equal to, or less than, the point of maximum curvature above the inflection point (e.g., the inflection point in the second phase) on a graph of the amount of fucosylation vs. decrease in GDP-fucose;

ii.1.a) approximately equal to, or less than, the lowest level that results in a normal (e.g., that seen in an un-manipuated cell) level of fucosylation;

iii.a) approximately equal to or less than the point of maximum curvature below the inflection point on a graph of the amount of fucosylation vs. decrease in GDP-fucose;

iii.1.a) approximately equal to, or less than, the highest level that results in no further reduction in fucosylation;

iv.a) approximately equal to or less than point A on the curve in FIG. 1, or less than or equal to an analogous point on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control;

v.a) approximately equal to or less than that corresponding to an amount between points A and B on the curve in FIG. 1, or less than or equal to an analogous point on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control; or

vi.a) approximately equal to or less than point B on the curve in FIG. 1, or less than or equal to an analogous point on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control.

In one embodiment, said second preselected level of GDP-fucose is selected from a level:

i.b) approximately equal to, or greater than, 10%, 15%, 20%, 25%, 30%, 35% or 40% of a reference level, e.g., the level in said cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation;

ii.b) an amount that provides an unacceptable level of fucose deprivation, e.g., an amount that results in decrease of GDP-mannose, e.g., a decrease in GDP-mannose that is equal to, greater than, 10%, 20%, 30%, 40% or 50% than a reference levee, e.g., the level of GDP-mannose in a cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation;

iii.b) an amount that provides an unacceptable level of fucose deprivation, e.g. an amount that results in a level of high mannose structures that are less than or equal to 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of a reference level

iv.b) an amount that provides an unacceptable level of fucose deprivation, e.g., an amount that results in accumulation of GDP-mannose, e.g. an increase in GDP-mannose that is equal to or greater than 2×, 3×, 4×, 5×, 6×, 7×, 8×, 9×, or 10× of a reference level, e.g. the level of GDP-mannose in a cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation;

v.b) an amount that provides an unacceptable level of fucose deprivation, e.g., an amount that results in accumulation of high mannose structures that are more than or equal to 2×, 3×, 4×, 5×, 6×, 7×, 8×, 9×, or 10× of a reference level;

vi.b) approximately equal to or greater than point C on the curve in FIG. 1, or greater than or equal to an analogous point on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control.

In an embodiment the first level is i.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is ii.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is ii.1.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is iii.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is iii.1.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is iv.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is v.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is vi.a and the second level is selected from i.b, ii.b, iii.b, iv.b, v.b, and vi.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is i.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is ii.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is iii.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is iv.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is v.b.

In an embodiment the first level is selected from i.a, ii.a, ii.1.a, iii.a, iii.1.a, iv.a, v.a, and vi.a and the second level is vi.b.

In an embodiment the level of GDP-fucose is between point B and C on the curve in FIG. 1 or in an analogous range on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control.

In an embodiment the level of GDP-fucose is between point A and C on the curve in FIG. 1 or in an analogous range on a plot of the amount of fucosylation (%) vs. the amount of GDP fucose as a % of control.

In one embodiment, the level of GDP-fucose is selected to be outside the range between A and B on the curve in FIG. 1 (as relatively small changes in GDP-fucose will result in relatively large changes in the amount of fucosylation. In an embodiment the level is also less than B.) In another embodiment, the level of GDP-fucose is reduced by a predetermined level, e.g., in comparison with a reference. In another embodiment, the reference is the amount present in a cell or batch of cultured cells, e.g., a CHO cell or batch of cultured cells, lacking the manipulation but otherwise the same or essentially the same as the cell having the manipulation. In another embodiment, the level of GDP-fucose is reduced by, as much as, or more than, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 or 90%, as compared to the reference.

In one embodiment, the method further comprises evaluating the glycoprotein for a parameter related to fucosylation, e.g., the proportion of a preselected glycan component which bears a fucosyl moiety, e.g., at a selected position on the glycan component, e.g., in a preparation of glycoproteins.

In one embodiment, the level of fucosylation at one, two, three, or more preselected amino acid residues is evaluated. In another embodiment, the level of fucosylation is reduced by a predetermined level in comparison with a reference. In another embodiment, the reference is the amount present in a cell or batch of cultured cells, e.g., a CHO cell or batch of cultured cells, lacking the manipulation but otherwise the same or essentially the same as the cell or batch of cultured cells having the manipulation. In another embodiment, the level of fucosylation is reduced by, as much as, or more than, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 or 90%, as compared to the reference.

In one embodiment, X_Fis greater than X_G,

and wherein,

X_Fis the % or proportion of reduction in the level of fucosylation (e.g., as compared to the level of fucosylation in a cell or batch of cultured cells lacking the manipulation); and

X_Gis the % or proportion of reduction in the level of GDP fucose (as compared to the level of GDP fucose in a cell or batch of cultured cells lacking the manipulation).

In one embodiment, said manipulation is not a genetic lesion or the presence of an siRNA that reduces the level of an enzyme that promotes formation of GDP-fucose, or the attachment of a fucosyl moiety. For example, the manipulation is not a lesion that decreases the expression of GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter. In another embodiment, the cell or batch of cultured cells is wild-type for one or all of GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter. In another embodiment, the cell or batch of cultured cells does not include an siRNA that targets GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter. In another embodiment, absent the manipulation, the level of fucosylation is substantially the same as the level in a wild-type cell. In another embodiment, the manipulated cell carries no mutation that substantially lowers GDP-fucose levels. In another embodiment, the manipulated cell has no siRNA that substantially lowers GDP-fucose levels.

The mutation can be in the structural gene which encodes GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter. Such mutations can decrease the activity of the encoded protein. The decrease can be partial or complete. Such mutations can act, e.g., by altering the catalytic activity of the protein or by altering its half-life. Other exemplary mutations can be in a sequence that control expression of GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter. These can be mutations that completely, or partially, reduce the expression of the gene, at the RNA or protein level. Such mutations include deletion or other mutations in endogenous of control sequence. Such mutations also include the introduction of heterologous control sequence, e.g., the introduction of heterologous control regions, e.g., a sequence that will give a desired level of expression. (A heterologous control sequence is a sequence other than a sequence naturally associated with and operably linked to the structural gene.) In embodiments the manipulation comprises a mutation in the structural region or in a control sequence operably linked to the gene.

In an embodiment a cell having a mutation that that decreases the level of GDP-fucose, e.g., a mutation that decreases the activity of GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter is cultured in the presence of a substance, e.g., fucose, that results in a GDP-fucose level and/or a fucosylation level described herein. In an embodiment the cell includes a mutation that, in the absence of fucose in the culture medium, would result in a cell having an unacceptably low level of GDP-fucose. When, however, cultured under the appropriate conditions, e.g., media supplemented, e.g., with fucose, that cell can exhibit a desired level of GDP-fucose, e.g., a level of GDP-fucose described herein. Thus, fucose or another substance is present in the culture medium at a level that results in a level of GDP-fucose recited above.

In another embodiment, the manipulation is the presence of an siRNA that reduces the level of an enzyme that promotes formation of GDP-fucose, or the attachment of a fucosyl moiety, e.g., an siRNA that targets GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter, and fucose or another substance is present in the culture medium at a level that results in a level of GDP-fucose recited above.

In one embodiment, said culturing comprises culturing the cell in a medium that results in said level of GDP-fucose.

In one embodiment, the glycoprotein is an antibody. In another embodiment, the antibody has reduced core fucosylation. In another embodiment, the antibody is selected from the group consisting of Rituximab, Trastuzamab, Bevacizumab, Tositumomab, Alemtuzumab, Arcitumomab, Cetuximab, Trastuzumab, Adalimumab, Ranibizumab, Gemtuzumab [ozogamicin], Fanolesomab, Efalizumab, Infliximab, Abciximab, Rituximab, Basiliximab, Eculizumab, Palivizumab, Natalizumab, Omalizumab, Daclizumab, and Ibritumomab.

In one embodiment, the cell is a Chinese Hamster Ovary (CHO) cell. In another embodiment, the glycoprotein is an antibody. In another embodiment, the antibody has reduced core fucosylation. In another embodiment, the antibody is selected from the group consisting of Rituximab, Trastuzamab, Bevacizumab, Tositumomab, Alemtuzumab, Arcitumomab, Cetuximab, Trastuzumab, Adalimumab, Ranibizumab, Gemtuzumab [ozogamicin], Fanolesomab, Efalizumab, Infliximab, Abciximab, Rituximab, Basiliximab, Eculizumab, Palivizumab, Natalizumab, Omalizumab, Daclizumab, and Ibritumomab.

In one embodiment, the glycoprotein is selected from Table 1.

In one embodiment, the method further comprises culturing a plurality of the cells and separating as much as, or at least, 1, 10, 100, 1,000, or 10,000 grams of the glycoprotein from the cells. In another embodiment, the method further comprises combining the glycoprotein having reduced fucosylation with a pharmaceutically acceptable component and, e.g., formulating the glycoprotein having reduced fucosylation into a pharmaceutically acceptable formulation.

In one embodiment, the glycoprotein is analyzed by one or more of HPLC, CE, MALDI-MS and NMR.

In one embodiment, the method further comprises memorializing the result of the evaluation.

In one embodiment, the manipulation is, or is the product of, a selection for reduced levels of GDP-fucose. In another embodiment, the manipulation is, or is the product of, a selection for reduced fucosylation of a glycoprotein. In another embodiment, the manipulation comprises contact with, or inclusion in or on the cell or batch of cultured cells, of an exogenous inhibitor of an enzyme involved in GDP-fucose biosynthesis, e.g., a specific or non-specific inhibitor.

In one embodiment, the level of fucosylation at one, two, three, or more preselected amino acid residues is evaluated.

In one embodiment, one or more of said cell or said batch of cultured cells, said manipulation, and said glycoprotein, is selected on the basis that it or the combination will provide a glycoprotein having reduced fucosylation.

In one embodiment, one or more of said cell or said batch of cultured cells, said manipulation (or manipulations), and said glycoprotein, is selected on the basis that it or the combination will provide a level of GDP-fucose described herein, e.g., a level which gives a minimal level of fucosylation (e.g., with reference to a curve analogous to that in FIG. 1, the level is to the right of point B) but which is above a preselected level In some embodiments the level is above a level that gives an unwanted decrease in the level of GDP-mannose, e.g., a decrease in GDP-mannose that is equal to, or more than, 10%, 20%, 30%, 40% or 50% as compared to a reference level, e.g., the level of GDP-mannose in a cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation.

In some embodiments the level is above a level that gives an unwanted increase in the level of GDP-mannose, e.g., an increase in GDP-mannose that is equal to, or more than, about 2×, 3×, 4×, 5×, ×, 7×, 8×, 9×, or 10× of a reference level, e.g., the level of GDP-mannose in a cell or batch of cultured cells, e.g., a cell or batch of cultured cells which is otherwise similar, without the manipulation.

In one embodiment, the method further comprises providing a value for a parameter associated with a compound other than GDP-fucose, wherein a parameter for the compound, e.g., the level of the compound, is correlated to the level of GDP-fucose.

In another embodiment, the method further comprises providing a comparison of the value with a reference value, wherein optionally, a preselected relationship of the value to the reference value, e.g., greater than, equal to, or less than, is indicative of whether the level of GDP fucose is above, at or below the second level. In another embodiment, the method further comprises, responsive to the result of the comparison, increasing the level of GDP-fucose, decreasing the level of GDP-fucose or continuing cell culture without intervening to change the level of GDP-fucose. In one embodiment, the compound other than GDP-fucose is GDP-mannose. In one embodiment, the compound other than GDP-fucose is GDP-mannose and the parameter is the level of GDP-mannose.

In one embodiment, the method further comprises providing a value for the level of GDP-mannose, providing a comparison of the value with a reference value, and responsive to the result of the comparison, increasing the level of GDP-fucose, decreasing the level of GDP-fucose or continuing cell culture at without intervening to change the level of GDP-fucose. In one embodiment, the method comprises continuing to culture said cells, and repeating the steps above.

In an embodiment, an inhibitor, e.g., an inhibitor of GMD, FX, fucokinase, GFPP, GDP-fucose synthetase, or enzymes involved in the biosynthesis of GDP-mannose, is used, e.g., in the culture medium, to lower the levels of the GDP-fucose. In an embodiment the inhibitor can be guanosine-5′-O-(2-thiodiphosphate)-fucose, guanosine-5′-O-(2-thiodiphosphate)-mannose, pyridoxal-5′-phosphate, GDP-4-dehydro-6-L-deoxygalactose, GDP-L-fucose, guanosine diphosphate (GDP), guanosine monophosphate (GMP), GDP-D-glucose, or p-chloromercuriphenylsulfonate EDTA. The inhibitor can be used with a cell which is mutant or wildtype for one or more GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter.

In an embodiment the media contains a substance that can increase the level of GDP-fucose, e.g., butyrate or fucose. Such media can be used, e.g., with a cell having a mutation that eliminates or decreased the activity of one or more of GMD, FX, fucokinase, GFPP, GDP-synthetase, a fucosyltransferase or a GDP-Fucose transporter.

While some methods described herein rely at least in part on mutations in a gene that conditions the level of GDP-fucose other methods described herein do not. Thus, cells that are not mutant at key genes involved in maintaining GDP-fucose levels can be used to provide proteins having reduced fucosylation. Levels of GDP-fucose can, e.g., be manipulated by culture conditions.

Thus, in another aspect, the invention features, a method of reducing fucosylation of a glycoprotein or a preparation of glycoproteins, the method comprising:

providing a cell that expresses said glycoprotein and that is wild-type for one or more (or all) of GMD, FX, fucokinase, GFPP, GDP-Fucose synthetase, a fucosyltransferase or a GDP-Fucose transporter;

culturing said cell under conditions that result in a level of GDP-fucose in said cell that is below a first preselected level and, in embodiments, above a second preselected level, and results in a preselected level of fucosylation, which is less than in a reference cell cultured under reference conditions, e.g., to provide a batch of cultured cells;

optionally, measuring the level of GDP-fucose in said cell or batch of cultured cells; and

optionally, separating the glycoprotein from at least one component with which said cell or batch of cultured cells was cultured,

optionally, evaluating the glycoprotein (or a glycoprotein on the surface of the cell or batch of cultured cells) for a parameter related to fucosylation;