Effects of dexamethasone on cell-mediated immune responses in cattle sensitized to Mycobacterium bovis

• Published in: American journal of veterinary research Vol. 56; no. 10; p. 1300
• Main Authors: Doherty, M.L. (University College Dublin, Dublin, Ireland.), Bassett, H.F, Quinn, P.J, Davis, W.C, Monaghan, M.L
• Format: Journal Article
• Language: English
• Published: United States 01.10.1995
• Subjects: Animals; Anti-Inflammatory Agents - pharmacology; BOVIN; Cattle; CD2 Antigens - immunology; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - drug effects; CD8-Positive T-Lymphocytes - immunology; DEXAMETASONA; DEXAMETHASONE; Dexamethasone - pharmacology; EXPERIMENTACION IN VITRO; EXPERIMENTATION IN VITRO; Female; Flow Cytometry - veterinary; GANADO BOVINO; IMMUNITE CELLULAIRE; Immunity, Cellular - drug effects; Immunization - veterinary; Immunohistochemistry; INMUNIDAD CELULAR; INTERFERON; Interferon-gamma - biosynthesis; INTERFERONAS; Leukocyte Count - veterinary; LINFOCITOS; LYMPHOCYTE; MEDICAMENT; MEDICAMENTOS; MYCOBACTERIUM; Mycobacterium bovis - immunology; PRUEBAS CUTANEAS; Receptors, Antigen, T-Cell, gamma-delta - immunology; Receptors, Interleukin-2 - immunology; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Skin - drug effects; Skin - immunology; TEST CUTANE; Tuberculin - pharmacology; Tuberculin Test - veterinary; TUBERCULINA; TUBERCULINE; Tuberculosis, Bovine - immunology
• ISSN: 0002-9645; 1943-5681
• DOI: 10.2460/ajvr.1995.56.10.1300

Systemic administration of dexamethasone led to a significant reduction in the size of the tuberculin reaction in response to intradermal injection of bovine purified protein derivative in 18 cattle experimentally sensitized to Mycobacterium bovis (P 0.01) and 8 cattle naturally infected with M bovis (P 0.001). The reaction in 6 of the 7 M bovis-infected cattle that received dexamethasone was classified as negative for the standard interpretation of the single intradermal comparative tuberculin test. Significantly fewer BoCD2+ (P 0.05) and BoCD4+ T cells (P 0.001) were present at the reaction site and in blood of dexamethasone-treated cattle, compared with untreated control cattle. Significantly fewer cells expressing the interleukin-2 receptor and WC1+ gamma delta T cells (P 0.001), and a significantly greater number of cells expressing the ACT2 antigen (P 0.05) were found at the reaction site in dexamethasone-treated cattle than in controls. The number of BoCD8+ T cells at the reaction site and in blood was not significantly affected by administration of dexamethasone. In vitro production of interferon-gamma by lymphocytes incubated with bovine purified protein derivative also was significantly lower (P 0.01) in the dexamethasone-treated cattle