Age and Antibody Production I. Qualitátive Changes in Antisera Associated with Age

Summary Differences in the antibody production of animals of different ages indicate that there is a curve of development in the ability of such animals to produce antisera and that during the course of this immunologic maturation process there is also a change in the quality of the antisera elaborated. This hypothesis is substantiated by the following observations drawn from a series of studies with 79 antisera produced by active immunization of rabbits. 1.The “avidity” of fresh antisera agglutinating B. enteritidis produced in 22 “adult” animals was greater than that of antisera produced in 22 “young” animals. 2.The “avidity” of fresh antisera agglutinating B. enteritidis produced by 22 “adult” animals was only a little greater than that of antisera produced by 19 “aged” animals. 3.The trend of the differences in these three groups of animals seemed to be the same if— a .The antigen used in immunization were administered intraperitoneally or intravenously. b .The total amount of antigen administered to each animal were the same, or was based upon the weight of the animal. c .The antisera were tested after a fourteen-day period of immunization or after a thirty-one-day period. d .Thyroid were added or omitted from the diet of the animals. 4.These “avidity” differences were not dependent upon the titer of the sera. 5.The quantity of antibody produced by “young” animals was less than that produced by “adults.” There was some evidence that “aged” animals were less able to produce antibody than were the “adults.” 6.Certain applications of the statistical method to immunologic reactions were made. It is suggested that a definite value lies in the further use of similar methods in other immunologic studies.