CULTURED HUMAN DECIDUAL STROMAL CELLS EXPRESS B7-1 (CD80) AND B7-2 (CD86) AND STIMULATE ALLOGENEIC T-CELLS

The origin and function of decidual stromal cells (DSC), the main cell ular component of the decidua, are uncertain. Although the general con sensus is that they are fibroblastic cells involved in fetal trophobla st nutrition, several authors have demonstrated that these cells can c arry out immunological functions and that at least a subpopulation of them may be of hematopoietic origin. Human DSC precursors or predecidu al cells (preDSC) purified by expansion in culture express a surface p henotype recalling that of dendritic cells. In the present study, we s how by flow cytometry that these cells also express B7-1 (CD80) and B7 -2 (CD86), two antigens involved in the costimulation of T cells by an tigen-presenting cells. Cultured DSC were also able to stimulate allog enic T cells in vitro. Using an immunohistochemical technique, we foun d that in cryostatic sections of early human decidua, CD80 and CD86 we re expressed mainly by DSC located around the decidual vessels, a loca tion compatible with preDSC rather than fully differentiated DSC. Our results suggest that preDSC are involved in antigen presentation.