SIGNIFICANCE OF AN INVITRO PHENOMENON IN WHICH MURINE ERYTHROCYTES ARE LYSED BY AUTOLOGOUS SPLEEN-CELLS AND SPHERULES OF COCCIDIOIDES-IMMITIS

Spleen cells from mice immunized with a variety of antigens and incubated in vitro with killed spherules of C. imitis lyse 6-8 times more autologous murine erythrocytes than normal spleen cells and spherules. Cellular and biochemical events in this phenomenon were investigated to ascertain its significance. Kinetic studies suggested that hemolysis resulted from the activation of some immune cells by spherules. The capacity of spherules to activate these cells is rather unusual because, of the inert particles tested, only zymosan A and crude chitin demonstrated comparable activity. Although the hemolytic phenomenon occurred in serum-free medium, more lysis was effected by immune cells and opsonized spherules or zymosan A than by immune cells and untreated fungal particles. Sheep, chicken, and human erythrocytes were not lysed in the hemolytic phenomenon; Hb in chicken and sheep erythrocytes was oxidized. The murine erythrocyte lysis and oxidation of ovine Hb correlated with the reduction of nitroblue tetrazolium by immune cells adherent to spherules, and both phenomena appeared to be mediated by H2O2 released into the medium by activated cells. Spleen cells reactive with spherules could not be depleted by treatment with iron carbonyl, antiimmunoglobulin plus complement [C] or anti-brain-associated .theta. plus C, but they were partially or completely depleted after rosette formation with erythrocytes coated with antibody or murine C. Light and EM revealed that immune spleens contained more neutrophils than normal spleens, that these neutrophils reduced nitroblue tetrazolium after stimulation with phorbol myristate acetate and that they were the most prevalent cell type adherent to spherules fater incubation in vitro.