The ABL-MYC retrovirus generates antigen-specific plasmacytomas by in vitro infection of activated B lymphocytes from spleen and other murin lymphoid organs

ABL-MYC is a recombinant retrovirus that constitutively expresses the v-abl and c-myc oncogenes. When used to infect immunized mice this virus rapidly and efficiently induces plasmacytomas of which an unusually high percentage secrete antigen (Ag)-specific monoclonal antibodies. These findings suggested that ABL-MYC targets Ag-stimulated B cells for transformation and that infection of lymphoid cells in vitro might be a useful, alternative method for generating monoclonal, Ag-specific plasmacytomas (ASPCTs). Therefore, we used helper virus-free ABL-MYC to infect suspensions of cells from spleens and other lymphoid organs from mice that had been immunized with a variety of Ags and transplanted them into naive mice. The results show that ABL-MYC preferentially transforms splenocytes that are Ag-reactive. They also demonstrate that ASPCTs can be produced by in vitro infection of cell suspensions from the spleen, lymph nodes and Peyer's patches of mice that had been immunized intraperitoneally with sheep red blood cells, Escherichia coli core RNA polymerase or Epstein-Barr virus gp340 protein or immunized orally with live Giardia lamblia parasites. The ASPCTs usually consisted of one to three clones, secreted antibodies that were quantitatively and qualitatively similar to those obtained from hybridomas, and could continue to secrete Ag-reactive antibody over eight transplant generations.