Effect of in vivo stimulation of mice on the secretion of factor B of the alternative complement pathway by peritoneal macrophages

Abstract

After in vivo treatment of mice with thioglycollate medium, the amount of native factor B which could be detected in vitro in culture supernatants of peritoneal macrophages was much lower than that found in supernatants of macrophages taken from untreated mice. However, when the macrophages from thioglycollate medium-treated mice were cultured on a plastic surface covered with glutardialdehyde-linked bovine serum albumin, the culture supernatants contained larger quantities of native factor B than culture supernatants of macrophages from untreated mice under the same conditions. Thus, the effect of in vivo thioglycollate medium treatment on the in vitro secretion of factor B by peritoneal macrophages could be modulated by the culture conditions. Factor B in culture supernatants of macrophages obtained from both untreated and thioglycollate medium-treated mice was stable. It remained functionally active, and therfore uncleaved over a long incubation period at 37 degrees C. In addition, factor D activity was never detected in any culture supernatant.

Enhancement of Macrophage Survival and Complement Production by Factors from Cloned T Cells

“…The choice of a particular experimental model was in fluenced by the availability and ease of ob taining specific cell types, the stability of the phages which are active producers of many complement components. Mouse peritoneal macrophages have been used extensively for in vitro studies of C4 [4,20], factor B, and factor D [21]. However, in the case of C4, mouse PEC have been of limited usefulness for functional hemolytic studies, since they produce C4 only briefly and appear to pro duce a disproportionately small amount of functionally active C4 [4,20], Mouse PEC have been maintained successfully in short term cultures with radiolabeled amino acids to label C4 intrinsically for molecular weight determination and analysis of chain structure [4], Guinea pig PEC do not survive in culture as well as those of mouse, but functional C4 and C2 molecules continue to be produced for the duration of the experiments, and acti vation of macrophages can be used to en hance functional levels of these molecules molecules per milliliter supernatant, because the synthesis and/or release of C4 and C2 did not vary linearly with time, and the doseresponse curve itself is not linear.…”