Abstracts Biological Sciences

Studies on the control of antibody formation: the effect of passively administered antibody on the primary immune response.

by Robert A. Murgita

The passive administration of antibody before, simultaneously with, or shortly after antigen can result in a markedly suppressed or sometimes enhanced immune response. The effect of prior administration of two classes of 7S mouse anti-sheep red blood cell (SRBC) immunoglobulins on the primary immune response to SRBC was studied. Mouse gammaGl and gammaG2 immunoglobulins were isolated from serum by a combination of Pevikon-Geon zone electrophoresis followed by density gradient isoelectric focusing. The immunoglobulins were defined by qualitative and quantitative studies, and their effects on the primary response were determined by administering doses ranging from 0.5 mg to 0.001 mg of immunoglobulin two hours before injection of antigen. Specific gammaGI (gammaF) anti-SRBC antibody suppressed the primary response to SRBC at all concentrations. Specific gammaG2 (gammaG) anti-SRBC antibody suppressed at high concentrations, but with less efficiency than gammaGl antibody, and enhanced the response to SRSC at low concentrations. The suppressing and enhancing effects of the passively administered immunoglobulins were shown to be specific. The effect of mixtures of gammaGl and gammaG2 antibodies was intermediate between values obtained when each was given alone. The results suggest that the suppressive effect of anti-SRBC antibody is associated predominantly, if not entirely, with gammaGl antibody, and the enhancing activity is associated with gammaG2 antibody. The significance of these findings relative to the postulated mechanisms of action of antibody mediated suppression of the immune response is discussed.