Recognition of surface antigens on spermatozoa of the common carp (Cyprinus carpio L., Teleostei) using monoclonal antibodies and scanning electron microscopy.

The distribution of antigenic determinants, recognized by seven anti-carp spermatozoa monoclonal antibodies (MAbs) and two anti-carp spermatogonia MAbs were studied using fresh, unfixed carp spermatozoa. The location of the antigenic determinants was analysed in light- and in scanning electron microscopy, in the latter with the backscattered imaging mode. With all seven anti-carp spermatozoa MAbs a similar regular distribution of the immuno-gold labeling was present on heads, midpieces and tails of carp spermatozoa, whereas with the anti-carp spermatogonia MAbs only low or no labeling was observed. The regular distribution of antigenic determinants, as observed with the anti-spermatozoa MAbs in carp, is in agreement with data on agglutination of spermatozoa by autoantibodies in Salmo gairdneri and data on distribution of antigenic sites on spermatozoa in Xenopus laevis. It differs from data in mammals in which the presence of specialized domains on spermatozoa was shown. These results are discussed.