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Binding specificities of mono-and polyclonal antibodies to the protozoan oyster pathogenPerkinsus marinusChristopher F. ~u n g a n ' , Bob S. ~o b e r s o n~ ABSTRACT: In an effort to develop direct detection methods for Perkinsus marinus cells in host tissue and environmental samples, the production of both mono-and polyclonal antibodies specific for this apicomplexan oyster pathogen was attempted. A particulate hypnospore immunogen was isolated from infected oyster hemolymph following incubation in Ray's fluid thioglycollate medium. Polyclonal antisera produced in both mice and rabbits following immunization with this preparation exhibited high antibody titers for pathogen cell epitopes, but not for host oyster tissue epitopes. At least some antibodies to hypnospore antigenic determinants recognized common epitopes on trophozoite cells in infected oyster tissues, as well as on zoospores and other proliferative cells produced by incubation of infected oyster hemolymph in sterile seawater Polyclonal antibodies also recognized a diffusable, noncellular substance present in host oyster tissues in areas surrounding focal lesions. Rabbit polyclonal antibodies did not recognize 2 Dermocystldium species infecting salmonid fishes or Haplosporidlum nelsoni infecting eastern oysters Crassostrea virginica. These antibodies did recognize many, but not all. Perkinsus species infecting selected molluscan hosts worldwide. Monoclonal antibodies produced to date apparently recognize epitopes unique to the hypnospore immunogen.

An assay measuring the chemiluminescent response of hemocytes from the oyster Crassostea virginica was used to assess the effects of environmental pollutants on phagocytosis. In vivo and in vitro effects of heavy metals (copper, cadmium, zinc, and aluminum), pesticides (dieldrin and chlordane), and organic compounds (naphthalene and 2,4-dinitrophenol) on the chemiluminescent response of stimulated oyster hemocytes were tested. In most cases, exposure to a hlgh pollutant concentration resulted in a decreased chemiluminescent response. After in vivo treatment, the response of the hemocytes depended on the duration of exposure to the pollutant and pollutant concentration. Instances of both acclimation and cumulati\re toxlc~ty of pollutants were observed.

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