Abstract
Lymphoid cells present in spleen and lymph nodes of hyperimmune rabbits were found to be differentiated with respect to the class of immunoglobulin heavy chain which they contained. The relative proportions of cells containing the various heavy chains were as follows: alpha-chain (5 to 8%), micro-chain (14 to 21%), and gamma-chain (71 to 81%). The allotypic markers Aa1 and Aa2, found on heavy chains, were also found to be separately localized in cells of Aa(1)/Aa(2) heterozygous rabbits. The ratio of cells in spleen and lymph nodes containing the Aa1 marker to those containing the Aa2 marker varied with individual rabbits; the range was 53 to 88% Aa1 versus 12 to 47% Aa2.