Receptor editing can lead to allelic inclusion and development of B cells that retain antibodies reacting with high avidity autoantigens

J Immunol. 2005 Oct 15;175(8):5067-76. doi: 10.4049/jimmunol.175.8.5067.

Abstract

Receptor editing is a major B cell tolerance mechanism that operates by secondary Ig gene rearrangements to change the specificity of autoreactive developing B cells. In the 3-83Igi mouse model, receptor editing operates in every autoreactive anti-H-2K(b) B cell, providing a novel receptor without additional cell loss. Despite the efficiency of receptor editing in generating nonautoreactive Ag receptors, we show in this study that this process does not inactivate the autoantibody-encoding gene(s) in every autoreactive B cell. In fact, receptor editing can generate allelically and isotypically included B cells that simultaneously express the original autoreactive and a novel nonautoreactive Ag receptors. Such dual Ab-expressing B cells differentiate into transitional and mature B cells retaining the expression of the autoantibody despite the high avidity interaction between the autoantibody and the self-Ag in this system. Moreover, we find that these high avidity autoreactive B cells retain the autoreactive Ag receptor within the cell as a consequence of autoantigen engagement and through a Src family kinase-dependent process. Finally, anti-H-2K(b) IgM autoantibodies are found in the sera of older 3-83Igi mice, indicating that dual Ab-expressing autoreactive B cells are potentially functional and capable of differentiating into IgM autoantibody-secreting plasma cells under certain circumstances. These results demonstrate that autoreactive B cells reacting with ubiquitous membrane bound autoantigens can bypass mechanisms of central tolerance by coexpressing nonautoreactive Abs. These dual Ab-expressing autoreactive B cells conceal their autoantibodies within the cell manifesting a superficially tolerant phenotype that can be partially overcome to secrete IgM autoantibodies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Age Factors
  • Alleles
  • Animals
  • Autoantibodies / physiology*
  • Autoantigens / immunology*
  • Autoantigens / metabolism*
  • B-Lymphocytes / cytology
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / metabolism
  • Binding Sites, Antibody / genetics
  • Cell Differentiation / genetics
  • Cell Differentiation / immunology*
  • Cells, Cultured
  • Gene Rearrangement, B-Lymphocyte / immunology*
  • Hybridomas
  • Immune Tolerance / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Phosphorylation
  • RNA Editing / immunology*
  • Receptors, Antigen, B-Cell / genetics*
  • Receptors, Antigen, B-Cell / metabolism
  • src-Family Kinases / physiology

Substances

  • Autoantibodies
  • Autoantigens
  • Receptors, Antigen, B-Cell
  • src-Family Kinases