Publication Date:
2015-09-19
Description:
T follicular regulatory cells (T FR ) are a suppressive CD4 + T cell subset that migrates to germinal centers (GC) during Ag presentation by upregulating the chemokine receptor CXCR5. In the GC, T FR control T follicular helper cell (T FH ) expansion and modulate the development of high-affinity Ag-specific responses. In this study, we identified and characterized T FR as CXCR5 + CCR7 – "follicular" T regulatory cells in lymphoid tissues of healthy rhesus macaques, and we studied their dynamics throughout infection in a well-defined animal model of HIV pathogenesis. T FR were infected by SIV mac251 and had comparable levels of SIV DNA to CXCR5 – CCR7 + "T zone" T regulatory cells and T FH . Contrary to the SIV-associated T FH expansion in the chronic phase of infection, we observed an apparent reduction of T FR frequency in cell suspension, as well as a decrease of CD3 + Foxp3 + cells in the GC of intact lymph nodes. T FR frequency was inversely associated with the percentage of T FH and, interestingly, with the avidity of the Abs that recognize the SIV gp120 envelope protein. Our findings show changes in the T FH /T FR ratio during chronic infection and suggest possible mechanisms for the unchecked expansion of T FH cells in HIV/SIV infection.
Print ISSN:
0022-1767
Electronic ISSN:
1550-6606
Topics:
Medicine