Regulation of the expression of a mammalian idiotype in chickens.

Id-1, an idiotype associated with rat anti-Group A streptococcal carbohydrate (anti-SACHO) antibodies has not been detected in any other tested species immunized with Group A streptococcal vaccine (GASV). The immunization of chickens with rat Id-1 prior to challenge with GASV, however, induced the production of Id-1 and anti-Id-1 in some chickens. The concentrations of both idiotype and anti-idiotype were regulated by challenges with GASV. Thus, it appears that this non-mammalian species has the genetic potential to express the mammalian Id-1 network but such a potential is normally masked by regulatory pressures.