Elżbieta Mikulska-Skupień

Feline Infectious Peritonitis: Immunohistochemical Features of Ocular Inflammation and the Distribution of Viral Antigens in Structures of the Eye

Feline infectious peritonitis (FIP) is a serious, widely distributed systemic disease caused by feline coronavirus (FCoV), in which ocular disease is common. However, questions remain about the patterns of ocular inflammation and the distribution of viral antigen in the eyes of cats with FIP. This study characterized the ocular lesions of FIP including the expression of glial fibrillary acidic protein and proliferating cell nuclear antigen by Müller cells in the retina in cases of FIP and to what extent macrophages are involved in ocular inflammation in FIP. Immunohistochemistry for FCoV, CD3, CD79a, glial fibrillary acidic protein, calprotectin, and proliferating cell nuclear antigen was performed on paraffin sections from 15 naturally occurring cases of FIP and from controls. Glial fibrillary acidic protein expression was increased in the retina in cases of FIP. Müller cell proliferation was present within lesions of retinal detachment. Macrophages were present in FIP-associated ocular lesions, but they were the most numerous inflammatory cells only within granulomas (2/15 cats, 13%). In cases of severe inflammation of the ciliary body with damage to blood vessel walls and ciliary epithelium (3/15, 20%), some macrophages expressed FCoV antigens, and immunolabeling for calprotectin on consecutive sections suggested that these FCoV-positive macrophages were likely to be recently derived from blood. In cases of severe and massive inflammation of most ocular structures (4/15, 26%), B cells and plasma cells predominated over T cells and macrophages. These results indicate that gliosis can be present in FIP-affected retinas and suggest that breakdown of the blood–ocular barrier can allow FCoV-bearing macrophages to access the eye.

Experimental immunology Relationship between Yersinia enterocolitica antibody level and bacterial shedding after challenge in previously immunized pigs

AsymptomaticcarriersofYersiniaenterocoliticaareoftenfoundinpigswhicharethemainreservoir and source of human infection. Carrying of that bacteria is usually connected with a long-term shedding and microbiological contamination of the environment. Thus, the aim of this study was to determine the effectofimmunizationwitha suspensionofselectedstrainsofY.enterocoliticaonthedurationofpathogen sheddinginexperimentallyinfectedpigs. Fifteenpigsweredividedintothreegroups,twoexperimentalandonecontrol.Immunizingsuspension wasadministeredsubcutaneouslyindosesof2 ml(groupI)and5 ml(groupII)withthedensityof2.7◊10 9 CFU/mlofformaldehydeinactivatedcellssuspendedinphosphate-bufferedsalineintwoinjectionswithin an interval of two weeks. Pigs were experimentally infected with a 10 ml dose of a pathogenic strain of Y.enterocoliticaO:3withthedensityof2.7◊10 9CFU/mltwoweeksafterimmunization. Subcutaneous immunization stimulated higher antibody levels in group II, which was administered ahigherinoculantdoseof5 mlsuspensionwiththedensityof2.7◊10 9CFU/ml.Inthisgroup,shedding was not reported in two out of five pigs, and the period of pathogen excretion was shorter in comparison withgroupI andthecontrolgroup.ExperimentalimmunizationagainstinfectionscausedbyY.enteroco liticadidnotpreventpathogenshedding,butmerelylimitedtheintensityanddurationofbacterialexcre tion.