Radioimmunoelectrophoretic study of rabbit anti-protein antibodies during the primary response.

Radioimmunoelectrophoretic analysis disclosed similar primary antibody responses to several protein antigens. Discrete γ2 and γ1M antibodies were also demonstrated after fractionation of pooled, early antiserum by several physicochemical methods. The indirect method of radioimmunoelectrophoretic analysis, i.e., addition of I* antigen in inert carrier after removal of unreacted, soluble proteins following development of precipitin arcs with anti-rabbit protein sera, appeared to provide the clearest demonstration of the two antibody activities. Both γ2 and γ1M antibodies appeared simultaneously, usually 6 to 7 days after immunization, and had begun to decrease by 21 days. Other immunologically active, antigen-binding globulins were not observed. These data indicate that the concept of sequential synthesis of 7 S γ2 and 19 S γ1M antibodies previously postulated must be reexamined.