Macrophage-Lymphocyte Interaction in the Antigen-Induced Blastogenic Response of Human Peripheral Blood Leukocytes,

Abstract

Summary: Glass bead column purified lymphocyte suspensions have reduced blastogenic responses to antigen when compared to unseparated leukocyte suspensions in vitro. Culture of these purified lymphocytes on macrophage monolayers generally restored the cells response to antigen. The response to phytohemagglutinin (PHA) was unaffected by column purification. The antigens used were streptolysin O (SLO), streptokinase-streptodornase (SK-SD), purified protein derivative (PPD) and small pox vaccine (POX). The response of the unseparated leukocytes, separated lymphocytes and separated lymphocytes on monolayers were 76%, 74% and 74% blasts generated in response to PHA; 18%, 0.0% and 10.0% blasts generated in response to SLO; 14.0%, 0.5% and 8.5% in response to SK-SD; 6%, 0% and 6% in response to PPD; and 7.5%, 0% and 1% in response to POX. The response of separated and unseparated cells to antigen but not to PHA was found to be dependent on the density of cells in culture. For Leighton tubes the optimal cell concentrations were 3 to 4 × 106 lymphocytes and 0.2 to 0.6 × 106 macrophages per culture. Separation of the lymphocytes and macrophages by a semi-permeable membrane prevented the restoration of blastogenesis. These results are consistent with the view that macrophage uptake of antigen and macrophage-lymphocyte interaction are necessary for the blastogenic response of lymphocytes to antigen in vitro.