The invention relates to a method for improving PD-1
titer produced by
Chinese hamster ovary cells. The method comprises the following steps: inoculating the
Chinese hamster ovary cells into an initial culture medium for culturing; after the culture is performed for 48 hours, feeding a fed-batch culture medium every day, and maintaining the glucose concentration in the culture medium to be 1.3-1.7 g / L, the
galactose concentration to be 0.6-1.0 g / L and the L-
sodium lactate concentration to be 14-16 mM; the culture temperature is reduced, a fed-batch culture medium is fed every day, the glucose concentration in the culture medium is maintained at (2-2.8) g / L, the
galactose concentration is maintained at (1.7-2.2) g / L, and cells are harvested.
Galactose is introduced to serve as a second
carbon source, and control over the culture initial
metabolism environment and the
carbon source in the culture stage is combined, so that the maximum accumulation amount of
lactic acid is obviously reduced, the
cell culture period is remarkably prolonged, and the maximum
titer of the PD-1
antibody is remarkably improved compared with an existing process.