Cellular and Molecular Phenotypes of pConsensus Peptide (pCons) Induced CD8(+) and CD4(+) Regulatory T Cells in Lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with widespread inflammation, immune dysregulation, and is associated with the generation of destructive anti-DNA autoantibodies. We have shown previously the immune modulatory properties of pCons peptide in the induction of both CD4(+) and CD8(+) regulatory T cells which can in turn suppress development of the autoimmune disease in (NZB/NZW) F1 (BWF1) mice, an established model of lupus. In the present study, we add novel protein information and further demonstrate the molecular and cellular phenotypes of pCons-induced CD4(+) and CD8(+) T(reg) subsets. Flow cytometry analyses revealed that pCons induced CD8(+) T(reg) cells with the following cell surface molecules: CD25(high)CD28(high and low) subsets (shown earlier), CD62L(high), CD122(low), PD1(low), CTLA4(low), CCR7(low) and 41BB(high). Quantitative real-time PCR (qRT-PCR) gene expression analyses revealed that pCons-induced CD8(+) T(reg) cells downregulated the following several genes: Regulator of G protein signaling (RGS2), RGS16, RGS17, BAX, GPT2, PDE3b, GADD45β and programmed cell death 1 (PD1). Further, we confirmed the down regulation of these genes by Western blot analyses at the protein level. To our translational significance, we showed herein that pCons significantly increased the percentage of CD8(+)FoxP3(+) T cells and further increased the mean fluorescence intensity (MFI) of FoxP3 when healthy peripheral blood mononuclear cells (PBMCs) are treated with pCons (10 μg/ml, for 24-48 hours). In addition, we found that pCons reduced apoptosis in CD4(+) and CD8(+) T cells and B220(+) B cells of BWF1 lupus mice. These data suggest that pCons stimulates cellular, immunological, and molecular changes in regulatory T cells which in turn protect against SLE autoimmunity.