STABLE PRODUCTION OF RECOMBINANT HUMAN SPERM IMMOBILIZING ANTIBODY USING CDNA EXPRESSION VECTORS

PROBLEM: Sperm immobilizing antibodies present in sterile women may be one of the principal causes of immunological infertility. We already established cell lines that secrete recombinant human IgG sperm immobi lizing antibody using class-switched (from IgM to IgG) genomic immunog lobulin genes. However, these transfectants produced a small quantity of antibody and required continuous use of a medium with selective rea gents. We have now constructed cell lines that stably secrete the anti body in large quantities using immunoglobulin cDNAs and cDNA expressio n vectors. METHOD: The immunoglobulin heavy chain cDNA was cloned from transfectants that secrete the class-switched human IgG sperm immobil izing antibody. The light chain cDNA, which had already been cloned, a nd the heavy chain cDNA were inserted into the modified bovine papillo ma virus-based cDNA expression vectors BCMGSNeo and BCMGSHyg, respecti vely. These constructs were sequentially transfected into a mouse myel oma cell line by electroporation. RESULTS: The established transfectan ts produced recombinant antibody that retained human sperm immobilizin g activity in nonselective medium for at least 30 days. Moreover, the production of the antibody was increased three times over that of the previous cell lines. CONCLUSION: We have established an unique method that improves the production of sperm immobilizing antibody stably and in large quantities.