SEROLOGICAL DIFFERENCES AMONG PHOTOBACTERIUM-DAMSELA SUBSP PISCICIDA ISOLATES

Serological differences of Photobacterium damsela subsp. piscicida (= Pasteurella piscicida) isolates were determined using yellowtail (Seri ola quinqueradiata) and rabbit. antisera. In Oita, Japan, from June to October, 1995, Ph. damsela piscicida was isolated from net-pen cultur ed diseased yellowtail and sera were collected from fish cultured in t he same net-pen. Antisera against formalin-killed cells of three repre sentative isolates were raised in yellowtail and rabbits. The yellowta il antisera were absorbed with homologous or heterologous isolates and used for the agglutinating antibody absorption test. Crude lipopolysa ccharides were extracted from the isolates and analyzed by immunodiffu sion with rabbit antisera, As a result, three types or antigenic diffe rences were revealed among the isolates by the agglutinating tests wit h the sera of naturally infected fish and by the absorption tests usin g yellowtail antisera. Some common and distinctive antigens of the iso lates were found by immunodiffusion analysis with rabbit antisera.