Comparison of immunospecific antibody response in young and old chickens immunized with human IgG

Three groups of 18-month-old chickens and three groups of 5-month-old chick ens were immunized with human immunoglobulin G (IgG) using one of three adj uvants in the first injection (Freund's Complete Adjuvant (FCA), Freunds In complete Adjuvant (FIA) and Hunter's TiterMax (HTM)) following the same imm unization scheme. The specific antibody response in serum was measured by E LISA. In both older and younger chickens the serum antibody response in the FCA group reached a significantly higher level (P < 0.01) than in the FIA group and in the HTM group on week 5. The FCA group also had a significantl y higher (P < 0.01) response on week 10 compared to the HTM group. Other th an that, there was no significant difference between the three adjuvant gro ups in specific serum antibody response in older chickens. In the younger c hickens the specific serum antibody response in the FCA group was significa ntly higher (P < 0.05) than the response in the HTM group. There was no sig nificant difference in the chicken serum antibody response between the FCA and the FIA groups, nor was there a significant difference between the FIA and the HTM groups. Comparing the younger chickens and the older chickens i mmunized using the same adjuvant, the older chickens had consistently highe r titres than the younger chickens, although the difference was not always significant.