Binding of bursal, thymic and splenic lymphocytes to macrophages.

This study was carried out to examine the potential for chicken lymphocytes from the bursa of Fabricius, the thymus and the spleen to interact physically with glass-adherent peripheral blood monocytes (macrophages). Lymphocytes from all three sources were bound by macrophages. Under optimal conditions, over 90% of the macrophages had lymphocytes bound. Splenic lymphocytes from either bursectomized or normal chickens were capable of being bound by macrophages. The degree of macrophage—lymphocyte interaction varied with the duration of incubation and with the concentration of lymphocytes in culture. The number of lymphocytes bound to macrophages was reduced when binding was allowed to take place at 4°, or if macrophage monolayers were pre-treated with iodoacetate. Incubation of the macrophage cultures with cytochalasin B or pre-treatment of the macrophage monolayers with trypsin also reduced lymphocyte binding. Chicken immunoglobulin, fresh chicken serum, or antigen—antibody complexes had no apparent affect on macrophage—lymphocyte interaction. These data indicated the following: (1) the majority of macrophages derived from peripheral blood monocytes have a receptor for lymphocytes; (2) functionally immature thymic and bursal lymphocytes as well as splenic lymphocytes can be bound by macrophages; and (3) macrophage—lymphocyte interaction in the chicken has similar properties to that seen in mammals.