Immunological Studies of the Immobilization Antigens of Paramecium aurelia variety 2

Abstract

SUMMARY: An immunological study was made of Paramecium aurelia variety 2. The antigens which produce immobilization antibodies were studied and a survey of the antigenic types, or serotypes, manifested by variety 2 stocks carried out. The eight types found were titrated against several sera. Serotype B, when found in different stocks, was distinguished from stock to stock on the basis of reactions to homologous and heterologous sera. Stock-specific C serotypes were also found and the conditions for maximum stability of the C serotype occurring in different stocks determined. It has been shown by absorption experiments that: (a) antiserum against a single serotype has at least two antibodies directed against the immobilization antigen(s); (b) if there are two or more determinant groups in a serotype, these groups are on a single molecule. The possible serological bases for cross-reactions of serotypes controlled by the same genetic locus are discussed.