Studies on the immune response in chickens. IV. Generation of hapten-specific memory and absence of increase in carrier-specific helper memory in antibody response to sheep red blood cell antigen and its hapten-conjugate.

The role of carrier recognition in the hapten-specific antibody response of chickens to hapten (TNP) conjugate of sheep red blood cells (SRBC) was studied. The anti-TNP antibody response to the challenge with either TNP-SRBC or DNP conjugate of Salmonella enteritidis (DNP-Sal) of chickens previously primed with TNP-SRBC was definitely higher than that of unprimed chickens. Injection of TNP-chicken red blood cells, which did not provoke any significant primary anti-TNP response, also induced the memory for secondary anti-TNP response to the challenge with TNP-SRBC or DNP-Sal. The TNP-specific memory generated by stimulation with TNP-SRBC was adoptively transferable by spleen cells into cyclophosphamide (CY)-treated X-irradiated syngeneic recipients. On the other hand, the SRBC-specific memory for augmentation of anti-TNP response to the challenge with TNP-SRBC was never detected in chickens previously primed with either any of a wide range of doses (10(4)-10(8)) of SRBC, solubilized SRBC or SRBC fixed with formaldehyde, nor in CY-treated X-irradiated chickens receiving SRBC-primed spleen cells. The anti-TNP response of chickens to the challenge with TNP-SRBC was rather suppressed by the SRBC preimmunization. The passively administered anti-SRBC chicken serum also suppressed the response to TNP-SRBC. The carrier-specific suppressor activity generated by SRBC stimulation was not adoptively transferable by spleen cells. It is suggested from these results that the mechanism of amplification of the anti-hapten antibody response of chickens to hapten-SRBC conjugate is primarily mediated by the hapten-recognition, and carrier-recognition is more important for suppression rather than for amplification of the anti-hapten response, although the inductive mechanism for anti-hapten response itself should somehow involve the carrier recognition.