The invention discloses a method and application for screening an ultralow
fucose cell line. The invention provides a method for constructing
fucose deficit type host cells capable of expressing an
antibody and an IgG-
FC fusion protein, a detection method for the
fucose activity of the
antibody and the IgG-
Fc fusion protein, and concrete application of the
cell lines. The method provided by the invention is realized by highly-efficient knockout of fucose-based
transferase (FUT8)
gene in an
engineering cell producing the antibodies and the IgG-
Fc fusion protein through a TALEN (and / or
CRISPR) technology; and through lens culinaris
lectin (LCA) pressurizing,
gene sequencing and a
flow cytometry screening process, the host cells with highly-efficiently knocked-out fucose is obtained. Meanwhile, fucose deficit CHOK1 host cell lines are constructed into stable
engineering cell lines capable of expressing
antibody proteins; and after the antibody proteins are obtained, glycoform analysis is performed; and results show that fucose knockout efficiency reaches to 99% or above.