Equine cell-mediated immune response to Rhodococcus (Corynebacterium) equi.
A lymphocyte blastogenic assay was developed to serve as an in vitro correlate of cell-mediated immunity to Rhodococcus (Corynebacterium) equi (R equi) in the equine species. Lymphocytes obtained from a group of experimental ponies showed no response in cell culture to R equi heat extract or lysozyme extract antigens. Ponies were assigned to groups for experimental inoculation. Three ponies were inoculated subcutaneously with live R equi, 3 were given live R equi by intranasal and intratracheal routes, and 4 ponies were left untreated. Lymphocytes from all inoculated ponies had a mitogenic response to R equi antigens in lymphocyte blastogenic assays performed between the 7th and 40th days after inoculation. Lymphocytes from noninoculated control ponies remained unresponsive to R equi antigens. Delayed-type hypersensitivity reactions developed in all experimentally exposed ponies after intradermal administration of the R equi antigen preparations. In a 2nd phase of experimentation, blastogenesis assays were performed on lymphocytes from horses in herds with endemic R equi infections. Results indicated that many of the animals had significant (stimulation index greater than 2) cell-mediated responses to the bacterium, but there was no distinct correlation between the immune response and clinical history. These data indicated that cell-mediated immunity is involved in the interaction of the equine immune system with R equi.
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D003352:Corynebacterium / Q000276:immunology*; D003354:Corynebacterium Infections / Q000276:immunology / Q000662:veterinary*; D005260:Female; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses / Q000276:immunology*; D006968:Hypersensitivity, Delayed / Q000662:veterinary; D007111:Immunity, Cellular; D007428:Intradermal Tests / Q000662:veterinary; D008213:Lymphocyte Activation; D008297:Male
D000907:Antibodies, Bacterial