INHIBITION OF HUMAN-LYMPHOCYTE BLASTOGENESIS BY C-3 - THE ROLE OF SERUM IN THE TISSUE-CULTURE MEDIUM

Abstract

Preparations of the 3rd component of human complement (C3) inhibit human lymphocyte blastogenic response to mitogens and antigens when cultured in serum-free medium or in medium supplemented with 5% autologous serum (AS). When the culture medium was supplemented with 5% fetal calf serum (FCS), C3 failed to inhibit responses to mitogen (concanavalin A) or to antigen (streptolysin O); some FCS lots allowed stimulation rather than inhibition of the lymphocyte responses. When lymphocytes were cultured in serum containing equal amounts of FCS and AS, no inhibition was seen. C3 apparently enhances or has no effect on lymphocyte responses.