Antibody production in rabbits and chickens immunized with human IgG. A comparison of titre and avidity development in rabbit serum, chicken serum and egg yolk using three different adjuvants.

The antibody response in rabbits and chickens (serum and egg yolk) immunized with human immunoglobulin G was studied during a 1-year immunisation period comparing the efficacy of three adjuvants: Freund's complete adjuvant (FCA), Freund's incomplete adjuvant (FIA) and Hunter's TiterMax adjuvant (HTM). Monthly boosters of the antigen in saline were administered. Adjuvants were used in the initial immunisation and in a booster at week 26. FCA was found to result in the highest titre in both species. FIA was more efficient than HTM in mediating an antibody response in rabbits. In chickens, FIA resulted in similar antibody titres in serum and egg yolk. The effect of HTM was similar to FIA in chicken serum but lower in egg yolk. The titres obtained in rabbits were approximately a factor 1.5-2.0 higher than in the corresponding chicken groups. However, the antibody productivity of the chicken, when using the egg yolk as the antibody source, was a factor 5-10 higher than that of the rabbit depending on the adjuvant used. FCA and FIA resulted in similar antibody avidity in rabbits whereas HTM had a lesser effect. In chickens FCA initially resulted in the highest antibody avidity in both serum and egg yolk, but after the booster with adjuvant the antibody avidity became similar for all three adjuvants.