Age and Antibody Production II. Further Observations on Qualitative Changes in Antisera Associated with Age

Summary It has previously been demonstrated by us that the avidity of fresh antisera agglutinating B. enteritidis produced by the active immunization of young rabbits is greater than that of antisera produced in adult or aged animals. Additional observations on these sera led to the following conclusions: 1.These avidity differences diminish with the “aging” in vitro of the antisera. 2.Antisera partially separated from serum proteins by adsorption to kaolin and elution with glycocoll, exhibit the same trends in avidity differences as do fresh sera. 3.The temperature at which the observations were made did not affect the reaction. 4.Antisera agglutinating B. enteritidis obtained from animals of various ages exhibit similar avidity differences when tested against Eb. typhosus , that is, minor agglutinins exhibit the same qualities as do major agglutinins. 5.In antisera produced by the injection of a bivalent antigen composed of sheep erythrocytes and B. enteritidis , the hemolysin produced by the adult animal shows a greater avidity for its antigen than does the hemolysin produced by young or very aged animals. 6.The avidity of a given antiserum is a property characteristic of that serum, and not directly related to its titer.