CItANGES IN ElmCTlZOlmOP.ETIC MomLrrY oF 19S AND 7S ANTIBODIES SYNTIIESIZED BY RABBITS A~TER A SINGLE VIRUS INJECTION

A previous paper in this series (1) described marked differences in the kinetics of the formation of poliovirus (PV)-neutralizing antibody of 19S and 7S type. I t was also reported (2) that the antibodies produced in the rabbit after a single PV injection showed progressive changes in their electrophoretic mobility and avidity. The present study analyzes these sequential changes in the mobility of 19S and 7S type PV-neutralizing antibody of rabbit origin. The molecular type of antibody synthesized was identified by zone density gradient ultracentrifugation (1, 3) and/or by its sensitivity to dissociation with sulfhydryl reagents (4, 5). These studies have demonstrated two antibody populations associated with 7S ~-globulins which differ in their electrophoretic mobility ('Y1 and ~,~), and a systematic sequential change in the mobility ~ ~ ~'1) of macroglobulin antibody formed after a single antigenic stimulation. Further, certain antisera were found to contain small amounts of antibody which sedimented at a rate intermediate to that of 19S and 7S antibodies.