Earnhart Christopher G, Kaattari Stephen L
Department of Environmental and Aquatic Animal Health, School of Marine Science, Virginia Institute of Marine Science, College of William and Mary, P.O. Box 1346, Gloucester Point, VA 23062, USA.
J Immunol Methods. 2003 Jul;278(1-2):67-78. doi: 10.1016/s0022-1759(03)00227-8.
Concentrated culture supernatants containing the extracellular products (ECP) of the protozoan oyster parasite Perkinsus marinus were used to immunize mice. This preparation, produced by ultrafiltration, was found to be both poorly immunogenic and toxic to experimental animals. The possibility that these effects were due to toxic parasite products and/or medium constituents was examined. Co-administration of this material with highly immunogenic oyster hemolymph caused a substantive suppression of the specific antibody response to hemolymph, as well as a decrease in the number of epitopes recognized. Potential protein/protease toxin-mediated causes of the immunosuppression were addressed by heat denaturation and proteolytic inhibition of the concentrate; neither substantially enhanced immunogenicity. Analysis of media constituents revealed that the known immunomodulatory surfactant, Pluronic F-68 (PF68), used in the defined lipid concentrate supplement, was capable of eliciting significant immunosuppression. Although isolated protein antigens from P. marinus ECP remain highly immunosuppressive, separation of the protein antigens from the PF68 has enabled production of polyclonal antisera with a broader recognition of antigens.
