Nonspecific macrophage suppressor factor: its role in the inhibition of contact sensitivity to picryl chloride by specific T suppressor factor

Abstract

AbstractAnti‐picryl T suppressor factor was produced by culturing lymphoid cells from mice which were first injected with picryl sulfonic acid and then painted with picryl chloride. The supernatant was harvested at 48 h. Macrophage suppressor factor was produced by incubating peritoneal exudate cells (PEC) in T suppressor factor, washing and then adding antigen and taking the supernatant after incubation for 1 h. Immune cells incubated in the supernatant lost the ability to transfer contact sensitivity. The supernatant (macrophage suppressor factor) was nonspecific and inhibited the passive transfer of contact sensitivity to picryl chloride and oxazolone to a similar extent.Macrophage suppressor factor was only produced when PEC were incubated in anti‐picryl T suppressor factor and then exposed to picrylated antigen. Syngeneic thymocytes picrylated in vitro were the best source of antigen. Allogeneic thymocytes and regional lymph node cells picrylated in vivo by painting with picryl chloride were less effective. Picrylated mouse red blood cells and picrylated mouse gamma globulin were least effective.Macrophage suppressor factor differed from T suppressor factor in several ways. It was nonspecific, its molecular weight was lower (10000–20000 daltons), and it failed to bind to PEC. It also failed to bind to immune cells at 0°C.Although macrophage suppressor factor inhibited passive transfer when the mice were tested immediately afterwards (Chase‐Landsteiner transfer), it did not affect passive transfer when testing was delayed for a week. It is proposed that macrophage suppressor factor amplifies the effect of T suppressor factor.