The Elimination of Heterologous Serum Proteins and Associated Antibody Responses in Guinea Pigs and Rats

Abstract

Summary The rate of elimination of I* protein antigens was used as a method of observing immune responses in guinea pigs and rats when single, spaced injections of antigens (7.5 mg/kg) were administered. Animals exhibiting immune responses eliminated the labelled antigens at accelerated, immune rates similar to those described in rabbits. Also, the relationship of the rapid, immune elimination of antigen to the subsequent appearance of antibody was similar to that seen in the rabbit. However, the immune responses to soluble protein antigens in guinea pigs had longer induction periods and slower immune elimination of antigen than in rabbits. The slower immune elimination of antigen in guinea pigs than in rabbits was presumably the result of a slower appearance of antibody in guinea pigs since antigen-antibody complexes once formed were rapidly eliminated. In guinea pigs injected with I*BSA and I*RSA, circulating antigen-antibody complexes could only be demonstrated during the phase of rapid, immune antigen elimination. On the basis of observations in the guinea pig and rat, there is no apparent correlation between the type of protein antigen and the rate of nonimmune elimination or the length of the induction period prior to antibody synthesis. Determination of the rates of elimination of antigen was found to be as sensitive a method of testing for an immune response to BGG, HGG, and RGG in guinea pigs as was anaphylaxis.