The apparent inability of cyprinid fish to produce skin‐sensitizing antibody

Both egg albumin and horse serum failed to induce systemic anaphylactic shock in cyprinid fish. The production of skin‐sensitizing antibody by these fish to either horse serum, egg albumin or antigenic extracts of the cestode, Caryophyllaeus laticeps or the acantho‐cephalan, Pomphorhynchus laevis , could not be demonstrated by homologous passive cutaneous anaphylaxis (PCA) or by heterologous PCA reaction in guinea‐pigs. It was considered therefore, that fish are unable to produce such antibody, at least in response to these antigens, and that it is unlikely that skin‐sensitizing antibody is involved in the rejection of C. laticeps by dace Leuciscus lueciscus (L.). The phylogenetic origins of skin‐sensitizing antibody are discussed.