Macrophage-lymphocyte interaction in the formation of delayed-type hypersensitivity.

Macrophage-lymphocyte interaction was studied on 121 CBA mice during a 2-hour contact of lymph-node cells of non-immune mice with a monolayer of peritoneal macrophages of BCG-immunized mice and subsequent intravenous administration of 4.10(7) pre-incubated lymphocytes to syngenic recipients. Sensitivity to tuberculin was demonstrated in the recipients by means of blast-transformation reaction of spleen cells (stimulation index was evaluated according to incorporation of 3H-thymidine--SI = 1.32 +/- 0.40) using administration of tuberculin into the paws (Mantoux reaction--MR = 0.11 +/- 0.02 mm) and the cytotoxic effect (CTE) of the lymphocytes on tuberculin-loaded sheep-cell erythrocytes whose disintegration was assessed according to discharge of iron from the target cells (CTE = 13.98 +/- 2.73%). At transfer of intact lymphocytes after contact with non-immune macrophages, SI = 1.046 +/- 0.019; MR = 0.014 +/- 0.002 mm; CTE = 0.214 +/- 0.048%. The treatment of lymphocytes with indomethacin during the contact with macrophages induced idvere changes in the indices of delayed-type hypersensitivity (DTHS). The conclusion has been drawn that the antigen-presenting ability of macrophages can materialize in vitro.