Identification And Clinical Relevance Of Naturally Occurring Human Cd8+Hla-Dr+ Regulatory T Cells

ARRUVITO, LOURDES ; PAYASLIAN, FLORENCIA; BAZ, PLÁCIDA; PODHORZER, ARIEL ; MACHICOTE, ANDRÉS ; BILLORDO, ARIEL ; PANDOLFI, JULIETA ; SEMENIUK, GUILLERMO ; ARRIBALZAGA, EDUARDO; FAINBOIM, LEONARDO

Mar del Plata

Congreso; LIX Reunión Científico Anual (SAIC) y LXII Reunión Anual de Sociedad Argentina de Inmunología; 2014

Sociedad Argentina de Inmunología

The lack of responsiveness to self and non-self antigens is normally maintained by multiple mechanisms, including the suppressive activities of several T cell subsets. Here, we show that CD8+ T cells from both adult peripheral blood and umbilical cord blood mononuclear cells constitutively expressing HLA-DR represent a natural human CD8+ regulatory T cell subset (Tregs). Their suppressive effect appears to be cell-to-cell contact-dependent and may involve CTLA-4 signaling between neighboring T cells. These Tregs can be expanded in vitro and exhibit a suppressive capacity similar to that observed in ex vivo CD8+HLA-DR+ T cells. The high frequency of CD8+HLA-DR+ T cells we detected in patients with non-small-cell-lung cancer deserve further work to confirm their putative suppressor effect within the tumor.