The Effect of Tuberculin on Peritoneal Exudate Cells of Sensitized Guinea Pigs in Surviving Cell Culture

Abstract

Washed peritoneal exudate cells of guinea pigs with tuberculin sensitivity and of normal control animals were maintained in surviving cell cultures in stationary tubes. The culture medium was 20% normal homologous serum to which varying concentrations of old tuberculin, glycerin, or “purified protein derivative” were added. The cultures were studied by direct microscopy, by total viable cell counts, by vital staining with neutral red and trypan blue and by differential counts taking into account both cell type and cell size. The exudates contained polymorphonuclear leukocytes, lymphocytes, and large macrophages; but the predominant cell type was intermediate in size and appearance between the lymphocyte and macrophage, showing considerable cytoplasmic basophilia but ingesting neutral red in a manner characteristic of macrophages. A clearly defined drop in total cell count occurred early (18 hr) in tubes containing antigen, and a marked relative rise late (72–90 hr). The early fall involved all cell types but appeared to affect large macrophages markedly. The late rise was attributed largely to superior cell survival observed in the presence of antigen and in part to proliferation. The presence of antigen also produced a hastening of maturation of the intermediate cells and possibly of lymphocytes towards typical large macrophages. These findings are interpreted as suggesting a stimulatory effect of antigen on sensitive cells of at least one type. The implications of such an interpretation are examined briefly.