Effects of Peptide-Induced Immune Tolerance on Murine Lupus

Abstract

The regulation of autoimmunity and the molecular mechanisms by which different immune cells, including T cells, polymorphonuclear leukocytes (PMN-granulocytes), and B cells suppress autoimmune diseases is complex. We have shown previously that BWF1 lupus mice are protected from autoimmunity after i.v. injection or oral administration of tolerogenic doses of pCons, an artificial synthetic peptide based on sequences containing MHC class I and MHC class II determinants in the VH region of a J558-encoded BWF1 anti-DNA Ab. Several T cell subsets can transfer this tolerance. In this study, we determined the potential roles of granulocytes, B cells and regulatory T cells altered by pCons treatment in the BWF1 (NZB/NZW) mouse model of lupus. Immunophenotyping studies indicated that pCons treatment of BWF1 mice significantly increased CD4+FoxP3+ T cells, reduced the percent of B cells expressing CD19+CD5+ but increased the percent of CD19+CD1d+ regulatory B cells and increased the ability of the whole B cell population to suppress IgG anti-DNA production in vitro. pCons treatment significantly decreased the expression of CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) in CD8+ T cells. In addition, peptide administration modified granulocytes so they became suppressive. We co-cultured sorted naïve B cells from mice making anti-DNA Ab (supported by addition of sorted naive CD4+ and CD8+ T cells from young auto-antibody-negative BWF1 mice) with sorted B cells or granulocytes from tolerized mice. Both tolerized granulocytes and tolerized B cells significantly suppressed the production of anti-DNA in vitro. In granulocytes from tolerized mice compared to saline-treated littermate controls, real-time PCR analysis indicated that expression of interferon-induced TNFAIP2 increased more than 2-fold while Ptdss2 and GATA1 mRNA were up-regulated more than 10-fold. In contrast, expression of these genes was significantly down-regulated in tolerized B cells. Further, another IFN-induced protein, Bcl2, was reduced in tolerized B cells as determined by Western blot analyses. In contrast, expression of FoxP3 was significantly increased in tolerized B cells. Together, these data suggest that B cells and granulocytes are altered toward suppressive functions by in vivo tolerization of BWF1 mice with pCons and it is possible these cell types participate in the clinical benefits seen in vivo.

CD8+ T regulatory cells in lupus

“…T regs secrete inhibitory cytokines such as IL-10, TGF-β, and IL-35 that can suppress target cells including APCs and CD4 + CD25 − T effector cells. [ 68 , 69 , 125 , 126 ] For example, pCons-induced T regs secreted TGF-β and IL-10, [ 6 , 8 , 18 , 21 , 76 ] is also observed in other studies. [ 70 , 71 , 72 ]…”

“…We reported that both CD4 + and CD8 + T regs are functionally deficient in both BWF1 mice and patients with SLE (they are as well reduced in other autoimmune conditions). [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 76 , 77 , 78 ] While CD4 + T regs have been intensively studied, [ 63 , 64 , 65 , 66 , 67 ] less is known about the CD8 + T regs in the suppression of autoimmunity.…”

Dietary Supplementation with Transgenic Camelina sativa Oil Containing 20:5n-3 and 22:6n-3 or Fish Oil Induces Differential Changes in the Transcriptome of CD3+ T Lymphocytes

“…Moreover, the direction of mitogen-induced change in expression was reversed for a proportion (<2%) of differentially expressed genes irrespective of the test oil supplement. Two of the most down-regulated transcripts were considered anomalies, namely CD163, which is a macrophage-specific scavenger receptor [ 48 ], and CD1d, a marker expressed by antigen-presenting cells including CD19 + CD1d + regulatory B lymphocytes [ 49 ] that is also a target for invariant natural killer T cells [ 50 ]. One possible explanation is that there was low-level contamination of the T cell preparations with macrophages or CD1d + B cells that was not detected by routine assessment of the purity of the T cell preparation by flow cytometry.…”

Peptide-based immunotherapy in lupus: Where are we now?

“…A safe alternative to the use of drugs carrying important side effects has been the use of peptide-based tolerogenic therapeutics for the induction of immune tolerance to self-antigens though the inhibition of autoreactive T, B, and dendritic cells together with the promotion of the activity of immunoregulatory cell populations. [ 9 , 10 , 11 ] We discuss below the promise of peptide-based immunotherapies and related clinical trials.…”