[Metabolism of immunoglobulin receptors by lymphocytes maintained in mouse spleen at the peak of the primary response].

Splenocytes obtained from mice on the 5th day after the injection of sheep red blood cells (SRBC) lost irreversibly approximately 50% of their surface immunoglobulins in the course of four-hour in vitro incubation. On the contrary, there were no changes in the total amount of surface immunoglobulins following in vitro incubation of splenocytes obtained on the 9th day after the antigen injection. Metabolism of antigen-binding receptors of immune splenocytes was studied by the method of rosette-formation. Incubation for 20 hours of splenocytes obtained on the 5th day after the SRBC injection demonstrated a loss of 70% of rosette-forming (RFC). The remaining RFC belonged to the theta-positive lymphocytes with the half-life of their antigen-binding receptors of approximately 4 hrs. Similar half-life was found for the RFC receptors of mouse spleen on the 9th day after the antigenic stimulation. No reduction of the RFC count occurred during their in vitro incubation for 20 hrs. It is supposed that a reduction in the number of the RFC obtained at the peak of the primary immune response could result from the inability of immune lymphocytes to synthesize new receptors or from blocking the newly-formed receptors by a soluble factor produced by immune lymphocytes following their in vitro incubation.