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The surface characteristics of the mouse spleen cells mediating antibody-dependent cytotoxicity (ADCC) against antigen-coated chicken erythrocytes have been studied by several different column fractionation methods. The major effector cells in this system were shown to be surface-adherent and could be depleted from spleen cells by passage through glass-bead ovalbumin/anti-OA immune complex columns (Fc receptor-binding), glass-bead immunoglobulin/anti-mouse Ig columns (Fc receptor- and surface immunoglobulin-binding), and glass-bead mouse Ig/rabbit (Fab')2-anti-mouse Ig or Sephadex G-200/rabbit anti-mouse Ig columns (surface immunoglobulin-binding). The concentration of EDTA in the medium used to fractionate the cells played a significant role in determining whether surface immunoglobulin could be demonstrated on the ADCC effector cells. From these results, the conclusion was drawn that ADCC on the part of mouse spleen cells could be mediated by surface-adherent, Fc receptor-positive cells bearing surface immonoglobulin of unknown origin. The possibility that ADCC can be mediated by a heterogenous population of cells in the mouse spleen is discussed. [ABSTRACT FROM AUTHOR]

With a modified rat mast cell degranulation (RMCD) technique developed by Korotzer, Haddad and Lopapa (1971), the mechanism of mast cell degranulation by IgE-anti-IgE reaction and the inhibitory effect of cAMP-related compounds upon IgE-mediated mast cell degranulation were studied. Degranulations of 90 per cent or more were decreased to 13-16 per cent when the mast cells were pretreated with human IgE or normal human serum. However, if rat mast cells were pretreated with anti-human IgE rabbit serum or normal rabbit serum, the degranulation per cent in these cells by IgE-anti-IgE reaction was the same as in the nontreated cells. These results suggest the presence of receptors in rat mast cells for human IgE or normal human serum, and the lack of receptors in these cells for anti-human IgE rabbit serum or normal rabbit serum. Treatment of isolated rat mast cells with adenyl cyclase stimulating agents (isoprenaline, adrenaline, prostaglandin E1 and E2 and theophylline or amino-phylline, which inhibit the enzymatic degradation of cAMP, also inhibit the morphological degranulation of the mast cells. Cromoglycate or chlorophenes in derivatives, which might have a stabilizing effect of the cell membrane, also inhibited the degranulation of the rat mast cells mediated by IgE-anti-IgE reaction. These results support the attractive hypothesis that cAMP occupies a central modulatory role in the in vitro mast cell degranulation in IgE-anti-IgE reaction. [ABSTRACT FROM AUTHOR]

Active uptake of sheep and chicken erythrocytes onto the surfaces of cockroach phagocytic haemocytes has been demonstrated to occur in vitro in the absence of haemolymph. Haemocytes were treated with various enzymes and chemicals in attempts to elucidate the nature of the receptor site for vertebrate erythrocytes. Uptake was abolished by pretreatrnent of haemocytes with trypsin and not restored by incubation in haemolymph. No opsonic activity was demonstrable for cockroach haemolymph regarding uptake of vertebrate erythrocytes. Cockroach haemocytes do not possess a receptor site for γ-globulin on their surfaces. [ABSTRACT FROM AUTHOR]