The inhibition of murine lymphocyte mitotic responses by human and mouse sera. I. Evidence for a role of antibody-independent activation of the alternative complement pathway.

摘要: Abstract The responses of mouse lymphoid cell cultures to mitogens such as concanavalin A or antigen were inhibited by the addition small amounts fresh human serum. This inhibitory effect was reduced specific decomplementation procedures heating at 50 °C inactivate factor B absorption with zymosan 17 deplete properdin from Human factor-B preparations reconstituted lost serum heated °C. These findings are interpreted indicate a fundamental role activation alternative complement pathway (ACP) an underlying mechanism inhibition. Additional experiments designed demonstrate natural antibodies activating classical pathway, while successful in these respects, also provided confirmatory evidence for antibody-independent ACP. Furthermore, data derived utilizing sera tested on syngeneic target cells, qualitatively similar results obtained employing sera. suggest that functional activities lymphocytes vitro ACP, implying this may exercise regulating lymphocyte function.