Clonal Expansions of CD8(+) T Cells with IL-10 Secreting Capacity Occur during Chronic Mycobacterium tuberculosis Infection

Cyktor, Joshua C.; Carruthers, Bridget; Beamer, Gillian L.; Turner, Joanne

CD8 + T cells are an important component of the protective immune response to Mtb, as defined by studies showing that mice deficient in CD8 + T cells had impaired control of Mtb infection [7] [8] [9] [10] . Although there is no consensus on the specific requirement for CD8 + T cells during Mtb infection, CD8 + T cells can contribute to Mtb control by secretion of IFN-c [11, 12] and cytotoxic lysis of host cells [13, 14] , yet their ability to maintain maximal effector function is dependent on CD4 + T cells [15] [16] [17] . Studies have also reported that CD8 + T cells are most important during latent Mtb infection in mice, and that CD8 + T cell depletion early after infection had little effect on disease outcome [18] . Conversely, other studies suggest that CD8 + T cells are dispensable during Mtb infection [19] [20] [21] .