Characterization of regulatory T cells by flow cytometry: current status and controversies
Abstract
The ability to maintain proper balance between immune activation and inhibition is required to develop an effective immune response without immunopathogenic processes associated. Different effector mechanisms that allow the elimination of exogenous agents and the presence of a regulatory system guarantee the physiological immune response and maintain the tolerance to self antigens.Among the regulatory mechanisms, the function of CD4+ T lymphocytes, in particular, the regulation exerted by natural regulatory T cells (nTreg), is important to underline. The phenotypic and functional characterization of these cells is a complex process, due to the absence of a cell marker that allows their specific identification by flow cytometry, a tool that has made possible the characterization of most of the immune cells.Currently, the combined use of monoclonal antibodies to identify CD4+/CD25high/Foxp3+/CD127low/- T lymphocytes has been proposed as the most specific alternative to determine the frequency of nTreg. For functional analysis, the identification of nTreg based on the expression of FoxP3 is not possible, since this is an intracellular molecule that requires the permeabilization of the cells for their identification. Once the cells are pure, their functional activity could be evaluated by different methods, including measuring their effect on the function of effector T lymphocytes.Based on these limitations the search for new molecules that allow a better characterization of these cells by flow cytometry continues and most likely a combination of this powerful tool with recent molecular findings (FoxP3 gene methylation pattern) will give a more precise alternative to study this cell subpopulation.Downloads
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