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Summary For many years, tonsillectomy has been used routinely in children to treat chronic or recurrent acute tonsillitis. Palatine tonsils are secondary lymphoid organs and the major barrier protecting the digestive and respiratory tracts from potential invasive microorganisms. They have been used as sources of lymphoid tissue; however, despite the hundreds of papers published on tonsillectomy, no studies addressing the functionality of the CD4+ and CD8+ T cells from chronically infected tonsils have yet been published. The aim of this study was to analyse the functionality of the CD4+ and CD8+ T cells with respect to tonsillar tissue. We used an affordable approach to measure the frequency of antigen-specific CD4+ T cells, the direct ex-vivo cytotoxicity of CD8+ T cells, memory T cell phenotype, cytokine profile and DC phenotype. Our results demonstrate that CD4+ and CD8+ T cells from tonsillar tissue are totally functional, as shown by their ability to produce cytokines, to degranulate and to differentiate into effector-memory T cells. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the proportion, phenotype, and cytotoxicity of CD8+CD57+ and CD57− T cells in peripheral blood from 20 tuberculosis (TB)-patients and 20 healthy tuberculin skin test-positive donors. Our results showed an increase in CD8+CD57+ T cells from TB-patients as compared with those from age-matched healthy donors (p <0.0001). CD8+CD57+ T cells from TB-patients expressed CD69, perforin, granzyme-A, and a CD28−CD62L−CD161− phenotype without recognition for the alpha-galactosylceramide–CD1d complex. This cell subset also expressed TNF-α and IFN-γ, under phorbol-myristate-acetate/ionomycin stimulation. Interestingly, the cytotoxicity against autologous monocytes was higher in CD57− cells from TB-patients and donors than their CD57+ counterparts, in the presence of Mycobacterium tuberculosis H37Rv culture filtrate. However, only CD8+CD57+ T cells from TB-patients exhibited spontaneous cytotoxicity against monocytes in the absence of antigen. Our results suggest that CD8+CD57+ T cells are a subset of effector cells that could be helpful to evaluate the cell-mediated immune response to M. tuberculosis. [Copyright &y& Elsevier]