Identifying Antigenic Determinants on Cytochrome c for B and T Cells

Abstract

Localization of the antigenic determinants on the cytochrome c molecule reactive with rabbit antibodies has depended on the antigenic comparison of cytochromes c of known structure by quantitative cross reactions. In addition, antibodies to these regions can be isolated by affinity chromatography methods and the specificity of these “site specific” antibodies determined by their pattern of reactivity with cytochromes c of known structure. Such studies lead to the conclusion that a limited number of antigenic regions elicit antibodies when various cytochromes c are injected into rabbits. While the Drecise number of amino acids contributing to the structure of the antigenic determinant is not known, certain amino acids can be identified which make a decisive contribution to the specificity. In trying to obtain similar information about the location on cytochrome c of the antigenic determinants reactive with receptors on thymus derived cells one encounters limitations. Assays do not exist which can yield the type of molecular information about antigenicity that immunochemists have been able to obtain from a study of the antigen-antibody reaction.