Immunofluorescent detection of differentiation alloantigens (CA1) in the chicken.

Lymphoid cell surface alloantigens were detected by a triple-layer immunofluorescence technique. An antiserum raised against B locus-incompatible lymphoid cells also reacted with previously undefined differentiation antigens (CA1) which segregated between B locus homozygous (B14/B14) chickens of the same strain as the antiserum donor. CA1-positive chickens reacted with the antiserum by agglutination of red cells and staining of all peripheral lymphocytes and thymocytes but not bursal cells. Cross-absorption experiments have demonstrated that antigens expressed by red cells, T cells (both thymic and peripheral) and B cells (peripheral only) respectively, were of distinct specificity.