Antibody forming cell precursors among glass-adherent peritoneal exudate cells

Among glass-adherent peritoneal exudate cells (gaPEC), induced by an inoculation of 1% glycogen solution, about 4.5% were classified as antibody-forming cell precursors (AFCP) on the first day of culture by means of anti-mouse B-cell antibody (anti-B-Ab). They proliferated and differentiated into IgG-forming plasma cells when cultured with antigen and thymic RNA in vitro. Pretreatment of PEC with anti-B-Ab and complement suppressed the formation of plasma cells. AFCP had receptors for IgM-antigen complexes and for complement, both of which were independent of Ca++ and MG++ and resistant to treatment by pronase or phospholipase C. Cells bearing detectable receptors for EA (IgM) an EAC diminished by the 6th day when gaPEC were cultured with thymic RNA, but persisted longer in cultures without thymic RNA. The same percentages of cells demonstrated tartrate-resistant acid phosphatase activities but were devoid of esterase. Twenty to thirty percent of anti-B-Ab sensitive cells ingested latex particles. The proliferation kinetics of IgG-forming cells were studied through the 21st day of culture by means of peroxidase-labeled antibody staining methods.