Pneumologie 2008; 62 - P222
DOI: 10.1055/s-2008-1074418

The tuberculin skin test in mice mainly depends on interferon-gamma-producing CD4+ T- lymphocytes

C Hölscher 1, A Hölscher 1, T Schreiber 1, D Rückerl 1, P Adams 2, D Woodland 2, A McKenzie 3, F Brombacher 4, Y Iwakura 5, S Ehlers 6, C Lange 7
  • 1Junior Research Group Molecular Infection Biology, Research Centre Borstel, Germany
  • 2The Trudeau Institute, Saranac Lake, NY USA
  • 3MRC Laboratory of Molecular Biology, Cambridge, UK
  • 4Institute of Molecular Medicine and Infectious Diseases, University of Cape Town, Cape Town, South Africa
  • 5Centre of Experimental Medicine, Institute of Medical Science, University of Tokyo, Tokyo
  • 6Division of Molecular Infection Biology, Research Centre Borstel, Germany
  • 7Division of Clinical Infectious Diseases, Research Centre Borstel, Germany

The tuberculin skin test (TST) reaction depends on the presence and function of T lymphocytes. However it is still unclear whether numbers of T-cells or their ability to secrete interferon-gamma (IFN-g) are key to determine a TST reaction.

Defined numbers of purified CD4+ T-cells were isolated from Mycobacterium tuberculosis (Mtb)-infected wildtype mice and transferred into alymphoid gamma-c-RAG2-deficient mice. The antigen specificity and the ability to sectete IFN-g of transferred cells were verified by staining with IAb ESAT6(1–20) multimers and by an IFN-g ELISPOT assay. After subcutaneous injection of PPD into recipient mice, quantitative evaluation of the TST revealed that the degree of delayed-type-hypersensitivity (DTH) reaction was dependent on the amount of transferred cells. To further evaluate the cytokine-mediated immune regulation of a TST reaction, different cytokine/cytokine-receptor-deficient and -overexpressing mice were infected with Mtb. Analysis of the CD4+ T cell profile and quantification of the resulting TST showed that the degree of skin reaction correlated with an IFN-g -producing TH1 biased immune response. Whereas a TH2 differentiation appeared to counteract the development of a DTH, the reaction was independent on the presence of TH17 cells. To finally proof that a TST reaction depends on the production of interferon-gamma, CD4+ T cells purified from Mtb-infected wildtype and IFN-g -deficient mice were transferred into alymphoid mice. After subcutaneous injection of PPD, quantitative analysis of the resulting TST revealed that the skin reaction was mainly determined by the presence of IFN-g. Together, our results suggest that the TST not only depends on the presence of CD4+ T cells. Additionally, the degree of skin reaction appears to be critically mediated by the production of IFN-g. Hence, our findings may have important implications for the diagnosis of latent TB especially in immunocompromised patients.