Antibody activity and complement-mediated solubilization of precipitates during the immune response.
The avidity of antibodies against human serum albumin (HSA) and the complement-mediated solubilization of HSA anti-HSA precipitates has been investigated during the immune response in rats, mice, rabbits, and guinea-pigs. The avidity of the anti-HSA antibodies was quantitatively determined and expressed as the amount of HSA required to solubilize 50% of 10 ng HSA anti-HSA precipitate. In rats, from 25 to 100 days after primary immunization the avidity of the anti-HSA antibodies increased approximately 100-fold, whereas the affinity did not change significantly. The increase in avidity was accompanied by a thirty-six-fold decrease in the amount of immune precipitate that could be solubilized by complement. Booster injections of the rats did not prevent the increase in avidity (thirteen-fold) that occurred from 25 to 50 days after the first immunization; however, the subsequent eight-fold increase in avidity from 50 to 100 days could partially or completely be abolished by secondary immunizations. A close, inverse relationship between the avidity of the anti-HSA antibodies and the rate of complement-mediated solubilization was observed. In addition, an increase in avidity without a change in affinity of anti-HSA antibodies and a decrease in the rate of complement-mediated solubilization was found during the immune response against HSA not only in rats, but also in mice, rabbits, and guinea-pigs.
D000818:Animals; D000915:Antibody Affinity; D000917:Antibody Formation; D000936:Antigen-Antibody Complex / Q000502:physiology*; D002847:Chromatography, Agarose; D003165:Complement System Proteins / Q000502:physiology*; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006168:Guinea Pigs; D007106:Immune Sera / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000276:immunology*; D012995:Solubility; D013997:Time Factors
D000936:Antigen-Antibody Complex; D007106:Immune Sera; D012709:Serum Albumin; D003165:Complement System Proteins