Polyclonal stimulation of lymphocytes by macrophages

Abstract

To analyze the interaction between macrophages and splenic lymphocytes with reference to time and concentration, the Mishell‐Dutton system was divided into two experimental steps. Step 1 consisted of the cocultivation of spleen cells with various doses of macrophages for different periods of time, while in step 2 macrophages were removed, spleen cells transferred to fresh petri dishes and cultivated until plaque assay. Cocultivation of spleen cells with high doses of macrophages for 4–8 h markedly enhanced the DNA synthesis and plaque‐forming cell (PFC) response of sheep red blood cell‐stimulated and unstimulated cultures. A cocultivation longer than 24 h resulted in an inhibition of both DNA synthesis and PFC response of spleen cells. These studies suggest a nonspecific function of macrophages on proliferation and differentiation processes in‐antibody formation.