In vitro-activated human lupus T cells express normal estrogen receptor proteins which bind to the estrogen response element

We have shown that estrogen receptor (ER alpha, ERP) transcripts are expres sed in SLE and normal T cells. In this study, T cell nuclear extracts from female lupus patients and normal donors were tested for biologically active ER proteins capable of binding to the human estrogen response element (hER E) by electrophoretic mobility shift assays. When peripheral blood T cells were stimulated with 17 beta -estradiol (E2), PMA and ionomycin, two major retarded bands in T cell nuclear extracts exhibited a migration pattern sim ilar to slow migrating protein-ERE complexes in human breast cancer cell ex tracts. T cells cultured only with E2 did not have these complexes. The for mation of the complexes was inhibited by competition with the hERE cold oli gonucleotide and partially with anti-ER alpha antibodies. There was no nota ble difference in the migration pattern of ERE-binding proteins between the SLE and normal T cell extracts. Together, these results suggest that activ ated human T cells, whether lupus-derived or normal-derived, contain biolog ically active ER alpha proteins. Other factors may be responsible for diffe rential sensitivity of lupus T cells to estrogen.