Replacement of immunoglobulin receptors by lymphocytes contained in the mouse spleen at the peak of the primary immune response

Abstract

Spleen cells obtained from mice on the fifth day after injection of sheep's red cells (SRBC) irreversibly lose 50% of their surface immunoglobulin receptors during culture in vitro for 4 h. On incubation of spleen cells obtained on the ninth day after injection of the antigen no changes were observed in the total quantity of surface immunoglobulins. Metabolism of the antigen-binding receptors of immune splenic lymphocytes was studied by rosette formation. Culture of spleen cells obtained on the fifth day after injection of SRBC for 20 h showed that 70% of the rosette-forming cells (RFC) were lost. The remaining RFC belonged to θ-positive lymphocytes. The half-replacement time of their antigen-binding receptors was approximately 4 h. Replacement of receptors of RFC in the mouse spleen on the ninth day after antigenic stimulation takes place at the same rate. During culture of spleen cells for 20 h no decrease in the number of RFC was observed. It is postulated that the decrease in the number of RFC obtained at the peak of the primary immune response may be the result of inability of the immune lymphocytes to synthesize new receptors or the result of blocking the newly formed receptors by a soluble factor produced by immune lymphocytes during culture in vitro.