Role of Foxp3 in CD8+ T regulatory/inhibitory cells ability to suppression of autoimmunity defined by mircoarray analysis and silencing of target genes after tolerization of BWF1 lupus mice with pConsensus peptide (128.6)

Abstract

Abstract NZB/NZW Fl female (BWF1) mice, a model of SLE, after tolerization with an artificial peptide (pCONSENSUS, pCons) that is based on anti-DNA IgG sequences containing MHC Class I and Class II T cell determinants, develop regulatory CD4+CD25+T cells and inhibitory CD8+T cells, both of which suppress anti-DNA Ig production. In the present study, we analyzed 45,000 murine genes in a one- to- one comparison of white blood cells (WBC), CD4, and CD8 cell subsets from tolerized vs. non-tolerized mice. Results showed 448, 174 and 60 genes, respectively, that were differentially expressed by at least twofold. From the CD8+ T cells, we confirmed up regulation of several genes in cells from tolerized mice, including Foxp3, Trp-53, CCR7, IFI202B, bcl2, and IFNar1. Using tranfection of CD8+ T cells with siRNA for Foxp3, Trp-53 and CCR7, silencing of Foxp3 eliminated 60–100% of the suppressive capacities of CD8+ T cells from tolerized mice, as well as their ability to secrete TGFb. There was significant correlation between expression of Foxp3 and ability of CD8+ Ti cells to secrete TGFb. In contrast, silencing of Trp-53 and CCR7 did not abrogate suppressive capacity of these cells. In summary, suppressive capacity of CD8+ Ti in this system of tolerance depend in large part on expression of Foxp3, and there may be a bi-directional Foxp3/TGFb autocrine loop that determines the ability of the CD8+ T cells to control autoimmunity. Supported by NIH grants AI63515, AI 63515, AR53239 and Tina C. Foundation.