Antigen uptake in vivo by peritoneal macrophages from normal mice, and those undergoing primary or secondary responses.

The uptake of human serum albumin and ferritin by peritoneal macrophages from normal, primary and secondary response mice has been studied. Both antigens were ingested by the macrophages irrespective of whether they were injected simultaneously or sequentially. Less than 1 per cent of the cells ingested only one antigen. There was no indication that one antigen was ingested in preference to the other in any of the groups of mice. The significance of these findings for the immune response is discussed.