Delayed-type hypersensitivity skin responses associated with feline infectious peritonitis in two cats.
Two cats previously challenge-exposed and seropositive to feline infectious peritonitis virus (FIPV) were evaluated for delayed-type hypersensitivity (DTH) skin responses to intradermal FIPV. Before testing, cat 1 (FIP-resistant) had survived a severe experimental FIPV challenge-exposure and had remained asymptomatic, whereas cat 2 (FIP-susceptible) developed acute fulminant FIP after a considerably smaller virus challenge-exposure. Cat 1 developed a focal thickened plaque at the FIPV-injected skin site at 48 hours after injection. Histological examinations of serial punch biopsies from virus-inoculated skin revealed perivascular and diffuse dermal infiltrations of macrophages, lymphocytes and polymorphonuclear leucocytes which were maximal at 48 to 72 hours after injection. In contrast, cat 2 did not react grossly and showed only very mild dermal infiltrates at 72 hours after injection. The present findings of strong DTH responses to FIPV in a resistant cat and minimal responses in a cat with acute fulminant FIP suggest that certain in vivo cellular immune reactions may be associated with disease resistance.
Weiss
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RC
Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849.
Cox
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D000818:Animals; D002371:Cat Diseases / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D002415:Cats; D003333:Coronaviridae Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D006968:Hypersensitivity, Delayed / Q000382:microbiology / Q000662:veterinary*; D010538:Peritonitis / Q000276:immunology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D012882:Skin Tests / Q000662:veterinary