Further evidence for the role of macrophages in the initiation of lymphocyte trapping

Abstract

Evidence is presented to substantiate an earlier report that macrophages are the operative cells in the initiation of lymphocyte trapping. Several procedures which increase phagocytosis in mice of a soluble antigen (BGG), including transfer of specific serum or of adherent and non-adherent immune cells, or the transfer of in vitro sensitized macrophages, enhance the trapping potential of BGG. Animals tolerant to BGG trapped effectively when challenged with aggregated BGG, or when passively immunized and challenged with soluble BGG. The trapping defect in tolerant animals is thus due to a specific defect in immune responsiveness rather than an inherent failure of the trap mechanism. The dissociation between trapping and immune responsiveness is discussed.