Occurrence of hybridomas producing multispecific IgM in human x (human-mouse) fusions with lymphocytes from different human immune compartments.

Human lymphocytes derived from peripheral blood, the spleen and lymph nodes were fused to the HAT-sensitive heteromyeloma cell line CB-F7. The Ig-producing initial cell lines were selected, and the supernatants were further analyzed for specific antigen binding (ELISA). IgM-antibodies were found which reacted with self- and non-self antigens of different molecular origin (nucleotides, proteins, carbohydrate structures). These antibodies were called multireactive (multispecific). The multispecific IgM-producing human hybridomas occurred with higher frequencies in the spleen (6.9% of IgM-producers) cell fusions than in experiments where peripheral blood-derived lymphocytes were fused (2.7%). There were no hybridomas producing multireactive antibodies detected in fusion material from lymph nodes. The greatest number of multireactive IgM was seen when PBL from SLE or anti-HIV-positive patients were hybridized to CB-F7 cells. Representative cell lines were cloned and recloned. The multireactivity of the IgM produced by really monoclonal cells, however, was preserved.