GPEx® A Flexible Method for the Rapid Generation of Stable, High Expressing, Antibody Producing Mammalian Cell Lines

Abstract

A versatile system has been developed, which is capable of transferring genes of interest into a wide variety of mammalian host cells and offers a number of advantages over the other methods for production of antibodies. These advantages include; (1) Shorter timelines, (2) Improved consistency, (3) Higher specific productivities, (4) Better genetic stabilities, (5) Increased flexibility and (6) Ability to work on any cell line. The GPEx ® method utilizes replication defective retroviral vectors, derived from Moloney Murine Leukemia virus (MLV) and pseudotyped with Vesicular Stomatitis Virus Glycoprotein (VSV-G), to stably insert single copies of genes at multiple genomic locations into dividing cells. Retrovectors deliver genes coded as RNA that, after entering the cell, are reverse transcribed to DNA and integrated stably into the genome of the host cell. Two enzymes, reverse transcriptase and integrase, provided transiently in the vector particle, perform this function. These integrated genes are maintained through subsequent cell divisions as if they were endogenous cellular genes. By controlling the number of retrovector particles accessing the cell, multiple gene insertion (desirable for high yielding cell cultures) can be achieved without any of the traditional amplification steps. This chapter describes the use of the GPEx ® technology for transferring genes into Chinese Hamster Ovary (CHO) cells, for the purpose of consistently producing cell lines with high antibody production levels in a short amount of time (Fig. 4-1).