Responses in Rabbits to the Red Cell Alloantigen HgA.

Successive injections of HgA-positive red cells were given at intervals of 2-3 months to HgA-negative rabbits. In forty-four out of fifty-one animals, red cell survival became progressively shorter and, in the majority of instances, anti- HgA was found in the serum. Characteristically, the first survival curve was initially normal but showed 'collapse' after a mean interval of 17 days; following subsequent injections, cells were cleared at an accelerated rate. In the remaining seven HgA-negative rabbits the survival of HgA-positive red cells was either repeatedly normal or was subnormal after the first one or two injections and became almost normal following further injections. In four out of six of these animals, following additional injections of HgA-positive cells given in with FCA, anti-HgA became detectable in the serum, Thus, some animals which appeared to he non-responders to HgA as judged by normal survival of HgA-positive red cells after i. v. injection alone showed some response when antigen was also given in, with adjuvant. [ABSTRACT FROM AUTHOR]