Antigen-Specific Suppression of Humoral Immunity by Anergic Ars/A1 B Cells

Abstract

Autoreactive anergic B lymphocytes are considered to be dangerous because of their potential for activation and recruitment into autoimmune responses. Yet they persist for days and constitute ~5% of the B cell pool. We assessed their functional potential in the Ars/A1 transgene model, where anergic B cells express a dual-reactive antigen receptor that binds, in addition to a self-antigen, the hapten p-azophenylarsonate (Ars). When Ars/A1 B cells were transferred into adoptive recipients that were immunized with foreign proteins covalently conjugated with Ars, endogenous IgG immune responses to both were selectively and severely diminished, and the development of T helper cells was impaired. Approximately 95% inhibition of the anti-Ars response was attained with ~4000 transferred Ars/A1 B cells through redundant mechanisms, one of which depended upon their expression of MHC II but not upon secretion of IL-10 or IgM. This antigen-specific suppressive activity implicates the autoreactive anergic B cell as an enforcer of immunological tolerance to self-antigens.

Regulatory B cells require antigen recognition for effective allograft tolerance induction

“…T cells, the literature is more limited on the topic of Breg specificity. Several studies have identified specific subpopulations of B cells as immunoregulators in contact hypersensitivity or autoimmunity models, which may require appropriate antigen recognition 9,13,[24][25][26]. The work reported herein, however, provides the most complete demonstration of recognition being required for allograft tolerance.…”

Functionally responsive self‐reactive B cells of low affinity express reduced levels of surface IgM

“…Europium (Eu 3+ )‐based fluoroimmunometric assays were described previously . For quantification of total IgG1κ produced in vivo, 96‐well europium plates (Greiner Bio‐One, Frickenhausen, Germany) were coated overnight at 4°C with rat antimouse kappa (RαMκ) (mAb 187.1, generated in‐house) followed by treatment with blocking buffer (2% BSA, 1% gelatin in PBS) for 2 h at 37°C.…”

“…Europium (Eu 3+ )-based fluoroimmunometric assays were described previously [58,59]. For quantification of total IgG1κ produced in vivo, 96-well europium plates (Greiner Bio-One, Frickenhausen, Germany) were coated overnight at 4 • C with rat antimouse kappa (RαMκ) (mAb 187.1, generated in-house) followed by treatment with blocking buffer (2% BSA, 1% gelatin in PBS) for 2 h at 37 • C. Serum samples were diluted in blocking buffer and incubated at 37 • C for 2 h or overnight at 4 • C. IgG1κ antibodies were detected using biotin-rat anti-mouse IgG1 (mAb RMG1-1, Biolegend), and quantities were interpolated based on standard binding curves generated using IgG1κ (MOPC 31C) myeloma Ig (Sigma-Aldrich, St. Louis, MO).…”

Peripheral CD4+T‐cell tolerance is induced in vivo by rare antigen‐bearing B cells in follicular, marginal zone, and B‐1 subsets

“…Recently, Cahalan and colleagues [44] showed that naïve antigen-expressing B cells and antigen-specific T cells formed stable conjugates as early as 72 h after adoptive transfer, but this time point does not preclude the possibility that T cells had already been primed on B-cell-derived antigen presented by DCs. Wysocki and colleagues [8] showed that self-antigen-specific anergic B cells can induce tolerance, and that this was partially dependent on direct presentation of antigen the B cells had internalized via the BCR. Here, we used Ag-tg B cells in which peptide transfer to other APCs is prohibited to test whether small precursor numbers of antigen-bearing Fo, MZ, and B-1 B cells can interact with naïve antigen-specific T cells, and if so, what the functional outcome of such an interaction might be.…”