Four murine hybridomas capable of producing monoclonal antibodies (MR-18, MR-21, AT-83 and AT-86) to cell surface antigens of genus Chattonella (Raphidophyceae) were developed and an indirect fluorescent antibody techinque was used to test reactivity of the antibodies against various strains of genus Chattonella.
According to the reactivity with the monoclonal antibodies, the 19 strains of genus Chattonella could be divided into 5 groups (Type I-V). Seven strains, which were morphologically identified as C. marina, were divided into 2 groups, 5 strains of Type I, and 2 strains of Types II. Similarly, 10 strains of C. antiqua were divided into 2 groups, 2 strains of Type III, and 8 strains of Type IV. In addition, it became clear that one of two strains that had not been identified yet belonged to Type III, and another strain which did not react with any of these 4 monoclonal antibodies. This suggests that the latter may belong to another group Type V.
Furthermore, we tried to apply the antibodies to the field samples obtained from natural sea water. C. antiqua Type III was detected from the bloom occurring offshore Buzen in August, 1987 and C. antiqua Type III and IV were detected from the bloom occurring offshore Akashi in August, 1987.