Factors Affecting the Primary and Secondary Responses to Bovine Serum Albumin in Chickens

Abstract

Chickens were sensitized and challenged with bovine serum albumin for the purpose of studying the effects of variation in injection schedule, dosage, injection procedure, and age on the immune response. The increment in the immune response titer was linear with time when the interval between primary and secondary injections was varied from 3-36 weeks. A secondary response was observed in chickens when the 1st injection was 40 mg and the second injection was 1 or 40 mg; no evidence of a secondary response was obtained when 1 mg or 40 mg was used to challenge animals previously immunized with a 1 mg dose. There were no major differences in the primary response among groups which were given the same amount of antigen in 1 injection or 4 daily injections; a single 40 mg injection was a more effective challenge than a series of four 10 mg injections given at daily intervals. Only animals which were 6 weeks or older at the time of primary injection produced a typical secondary response upon challenge.