In vitro immunization for the production of antigen-specific lymphocyte hybridomas.

Antigen-specific lymphocyte hybridomas have been produced by a simple in vitro immunization procedure. Non-immune spleen cells have been activated in vitro, and the B-cell blasts have subsequently been used for somatic cell hybridization. Hybrids secreting monoclonal antibodies to human myoglobin, pig insulin, and benzo(a)pyrene were obtained with splenocytes that had been immunized 5 days in culture before the hybridization. The frequency of specific hybridomas was the same as or higher than that of hybridomas produced from in vivo-immunized cells, showing the versatility of the procedure when making monoclonal antibodies to haptens and proteins with a conserved structure or to small amounts of antigen. Monoclonal antibodies of both IgG and IgM isotypes could be isolated.