Application of Monoclonal Antibodies to Field samples of Alexandrium species.

Abstract

Eight monoclonal antibodies reactive against cultured cell surface antigens of genus Alexandrium (Dinophyceae) were tested for cross-reaction with natural field samples from Japanese coastal waters, by the indirect immunofluorescence (IIF) method.In advance of applying monoclonal antibodies to field samples, the reactivity of typical antibodies to cultured cells at various growth stages in asexual and sexual cycles were examined by dot immunoassay and IIF, respectively. As a result, the reactive intensities were constant during the exponential growth phase and decreased a little during the stationary phase. At a different stage of sexual reproduction, these antibodies reacted with the vegetative cells of parent and F1 progenies, but not with the planozygotes and cysts. The reactive spectra of these antibodies to the cells of natural field samples collected from Tanabe Bay (Wakayama Pref.) in May 1990 and 1991, from Ofunato Bay (Iwate Pref.) in June 1991, and from Tachibana Bay (Nagasaki Pref.) in July 1991 almost coincided with those of these antibodies to cultured cells of A. catenella, A. tamarense, and A. affine, respectively. The results of immunological analysis corresponded with those of the morphological features.These monoclonal antibodies appear to be useful for the identification of these organisms from natural sea water.