Increased proportion of antigen-specific antibody-producing hybridomas following an in vitro immunization with in vivo immunized mouse spleen cells.

Development of murine monoclonal antibodies to weakly immunogenic antigens was accomplished by combining both in vivo and in vitro immunizations. Following immunization of mice with Treponema hyodysenteriae outer membrane antigens, Manduca sexta apolipoproteins, and Drosophila melanogaster DNA polymerase, respectively, a significant increase in percentage of antibody-producing hybrids were identified when immune spleens were subjected to an in vitro immunization prior to fusion with SP2/0 myeloma cells. The hybrids developed, produced Abs to a T. hyodysenteriae 14 Kd carbohydrate, M. sexta apolipoproteins I, II, and III, and D. melanogaster DNA polymerase. The use of both in vivo and in vitro immunizations may increase the likelihood of generating monoclonal antibodies to weakly immunogenic antigens.