Human-human hybrids secreting pneumococcal antibodies.

Starting with a nonimmunoglobulin producing human myeloma cell line, we have constructed a human myeloma "analog" (LSM 2.7) which supports the synthesis and secretion of human immunoglobulin in vitro upon fusion with human peripheral blood and spleen mononuclear cells. Fusions between LSM 2.7 and spleen cells obtained from patients immunized against pneumococcal capsular polysaccharides consistently gave rise to hybrids which synthesized and secreted human immunoglobulin. In three of ten independent fusions a large proportion of the hybrid cultures produced specific pneumococcal antibodies. All three spleens which yielded antibody producing hybrids were from patients immunized 3 to 4 days prior to staging splenectomy for Hodgkin's disease. Antibody secreting hybrid cells ceased producing immunoglobulin 28 to 42 days post fusion. However, fusion of a HAT sensitive clone derived from a hybrid which had secreted antibody, with peripheral blood mononuclear cells, resulted in reactivation of specific antibody secretion.