CYTOPHILIC ANTIBODIES IN MICE IMMUNIZED WITH SHEEP RED CELLS

Antibodies cytophilic for homologous and heterologous (guinea pig, rat) peritoneal cells of the mononuclear phagocyte type were demonstrated in the sera of mice immunized with sheep red cells. The formation of these antibodies can be induced by immunization with red cells with and without complete Freund's adjuvant. They are also present, in varying titres, in the sera of non-immunized mice. The peritoneal cavity of normal and immunized mice contains cells which adsorb sheep red cells. This phenomenon is significantly reduced by preincubating the peritoneal cells for two hours in vitro at 37° C. The cytophilic activity of mouse sera can be abolished by absorption by spleen homogenate, but not by pulverized guinea pig kidneys. The haemolysin and haemagglutinin titres before and after absorption are practically the same. The cytophilic component of some sera was inhibited by 2-mercaptoethanol. Tests of the sera of mice revaccinated with sheep red cells showed, after separation on Sephadex G 200, that cytophilic activity was present mainly in the 7 S fraction, but also in the 19 S fraction. Cells adsorbing cytophilic antibodies stain supravitally with neutral red; in fixed and stained preparations they are typical macrophages and monocytoid mononuclears with varying degrees of affinity for basic dyes. © 1968 Institute of Microbiology, Academy of Sciences of the Czech Republic.