Regulation of the Immune Response — Role of the Macrophage

Abstract

MACROPHAGES facilitate a variety of thymus-dependent immunologic phenomena in human beings and laboratory animals; thus, these cells are essential for the development of cellular and humoral immunocompetence.^{1 ,}1a Their role in T-cell and B-cell function is shown schematically in Figure 1. Macrophages serve at least four distinct but interlocking functions in host defense. First of all, the induction of T-lymphocyte proliferation requires the physical association of the T cells with macrophages bearing antigen.1b Secondly, the macrophage is a principal site of control by the immune-response gene.² Thirdly, macrophages have several plasma-membrane receptors, such as those for the Fc portion of IgG, that . . .