Functional Modulation of Regulatory T Cells by XXXX .

@entity2047 @entity19 @entity3783 @entity1961 @entity3744
The suppressive function of regulatory T cells (Tregs) is critical to the maintenance of immune homeostasis in vivo and yet, the specific identification of Tregs by phenotypic markers is not perfect. Tregs were originally identified in the @entity1961 + @entity3783 + fraction of T cells, but @entity3744 expression was later included as an additional marker of Tregs as @entity3744 expression was identified as being critical to the development and function of these cells. Intracellular expression of @entity3744 makes it difficult in using to isolate live and not permeabilized cells for functional assays. As such @entity1961 + @entity3783 + fraction is still frequently used for functional assays of Tregs. Although, the @entity1961 + @entity3783 + fraction substantially overlaps with the @entity3744 + fraction, the minor mismatch between @entity1961 + @entity3783 + and @entity3744 + fractions may confound the functional characteristics of Tregs. In this study, we isolated @entity1961 + @entity3744 + as well as @entity1961 + @entity3783 + fractions from @entity3744 knock-in @entity19 , and compared their proliferative and suppressive activity in the presence or absence of various concentrations of @entity2047 . Our results showed comparable patterns of proliferative and suppressive responses for both fractions, except that contrary to the @entity1961 + @entity3783 + fraction the @entity3744 + fraction did not proliferate in an autocrine fashion even in response to a strong stimulation. In presence of exogenous @entity2047 , both @entity1961 + @entity3783 + and @entity1961 + @entity3744 + fractions were more sensitive than the @entity1961 + @entity3783 - responder cells in proliferative responsiveness. In addition, a low dose @entity2047 enhanced whereas a high dose abrogated the suppressive activities of the @entity1961 + @entity3783 + and @entity1961 + @entity3744 + fractions. These results may provide an additional understanding of the characteristics of the various fractions of isolated Tregs based on phenotype and function and the role of varying levels of exogenous @entity2047 on the suppressive activity of these cells.
