Comparative immunology of algal biliproteins.

The three spectroscopically distinct classes of phycobiliproteins characteristic of the Cyanophyta and Rhodophyta-phycocyanins, allophycocyanins, and phycoerythrins-share no common antigenic determinants detectable by the Ouchterlony double diffusion technique. Each class of phycobiliprotein, from both Cyanophyta and Rhodophyta, possesses a strong determinant common to all members of that class. With respect to an antiserum directed against a specific cyanophytan biliprotein, all heterologous biliproteins of the same class are immunologically identical, as shown by the fact that absorption with a given heterologous antigen simultaneously eliminates crossreactions with other heterologous antigens. A cryptophytan phycoerythrin was found to be immunologically unrelated to any of the cyanophytan or rhodophytan biliproteins examined.