A Rabbit with the Allotypic Phenotype: a1a2a3 b4b5b6

A rabbit of allotype a1a3, b4b5 was hyperimmunized with lyophilized Micrococcus lysodeikticus. Two weeks after the appearance of antibodies of restricted heterogeneity, the serum immunoglobulins of this animal reacted with anti-a1, anti-a2, anti-a3, and anti-b4, anti-b5, and anti-b6 allotype antisera. Control experiments showed that the reaction was specific for the allotypic determinants and that cross-reactions could be excluded. Isolated light chains were shown to contain the b4, b5, and b6 allotypic specificities. Serial bleedings indicated that all six allotypic specificities were present in most bleedings, but occasionally one or more of the allotypic specificities could not be detected.