Increased frequency of both total and specific monoclonal antibody producing hybridomas using a fusion partner that constitutively expresses recombinant IL-6.

The addition of auxiliary feeder cells or conditioned medium has been shown to augment the yield of mouse hybridomas obtained following the cell-cell fusion of myeloma and B lymphocytes. The addition of one of these factors, interleukin-6 (IL-6) has been found to increase the proportion of hybridomas secreting monoclonal antibodies of desired specificity. As an alternative genetic approach, we have examined the efficacy of a retroviral infectant of Sp2/0 cells that constitutively expresses recombinant murine IL-6 (Sp2/mIL-6) as fusion partner. The results demonstrated that the yields of both viable Ig-secreting hybridomas, and antigen-specific monoclonal antibodies were increased 3-15-fold and 5-9-fold, respectively, with the Sp2/mIL-6 relative to Sp2/0 or Sp2/neo cells as fusion partner. Sp2/mIL-6 cells generated hybridomas with comparable growth rates, stability, and Ig production. The results of staining nascent hybridoma colonies immunohistochemically for Ig production suggest that Sp2/mIL-6 cells as a fusion partner increased the viability and/or stability of nascent hybrid cells that are producing Ig. Thus the Sp2/mIL-6 cells are an improved myeloma parent for the generation of large numbers of antibody-producing hybridomas against specific antigens.