פרסומים

A heat stable factor (SF) in normal human serum which is cytotoxic to Landschutz ascites tumor cells has been described. The cytotoxic action requires the presence of human or rabbit complement but guinea pig complement is ineffective. The substance is found in the beta-globulin fraction and has characteristics similar to C'4 of human complement. It is selectively absorbed on human and mouse tumor cells and human placenta but not by normal human liver, kidney or heart. SF inhibits the action of heterologous antibody on ascites and HeLa cells. We are indebted to Dr. A. Rimon, Marcus Memorial Blood Bank Institute, Jaffa, for the Cohn fractions, and to Dr. Esther Tenenbaum of this Department for a generous supply of HeLa cells and Chang cells.

THE mechanism of cell destruction in allergic inflammation is not well understood. Two explanations for production of cell damage have, however, been proposed: (a) that the antigen-antibody reaction causes, in some non-specific manner, permeability changes in cells which result in the release of active mediators of inflammation (histamine, etc.) and that the latter are directly involved in the allergic process1; (b) that the antigen-antibody reaction activates proteolytic enzymes (plasmin, proteases) that injure the cells2–4.