High responder rabbits to SRBC, a familial incidence.

Three litters of rabbits from our closed colony when immunized with multiple i.v. injections of SRBC gave unusually high titers compared to other rabbits immunized in a similar fashion. Data suggest that this response is a familial occurrence. The antisera from the high responding rabbits also exhibited other unique properties in addition to the high agglutinin titers. The early bleedings had significantly higher amounts of IgG anti-SRBC antibodies but similar amounts of IgM anti-SRBC antibodies relative to normal rabbits immunized with SRBC. The IgG antibodies from the high responders were low avidity antibodies and may exhibit limited heterogeneity.