Activated CD4+ T cells enter the splenic T-cell zone and induce autoantibody-producing germinal centers through bystander activation

Eur J Immunol. 2014 Jan;44(1):93-102. doi: 10.1002/eji.201343811. Epub 2013 Nov 4.

Abstract

CD4(+) T (helper) cells migrate in huge numbers through lymphoid organs. However, little is known about traffic routes and kinetics of CD4(+) T-cell subsets within different organ compartments. Such information is important because there are indications that CD4(+) T cells may influence the function of microenvironments depending on their developmental stage. Therefore, we investigated the migration of resting (naïve), activated, and recently activated (memory) CD4(+) T cells through the different compartments of the spleen. Resting and recently activated CD4(+) T cells were separated from thoracic duct lymph and activated CD4(+) T cells were generated in vitro by cross-linking the T-cell receptor and CD28. The present study shows that all three CD4(+) T-cell subsets selectively accumulate in the T-cell zone of the spleen. However, only activated T cells induce the formation of germinal centers (GCs) and autoantibodies in rats and mice. Our results suggest that in a two-step process they first activate B cells independent of the T-cell receptor repertoire and CD40 ligand (CD154) expression. The activated B cells then form GCs whereby CD154-dependent T-cell help is needed. Thus, activated T cells may contribute to the development of autoimmune diseases by activating autoreactive B cells in an Ag-independent manner.

Keywords: Activated T cells; Development; Germinal center; Noncognate interaction; Rodent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adoptive Transfer
  • Animals
  • Autoantibodies / metabolism*
  • Bystander Effect
  • CD4-Positive T-Lymphocytes / immunology*
  • CD40 Ligand / genetics
  • Cells, Cultured
  • Germinal Center / immunology*
  • Immunologic Memory
  • Lymphocyte Activation
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Rats
  • Rats, Inbred Lew
  • Spleen / immunology*
  • T-Lymphocyte Subsets / immunology*

Substances

  • Autoantibodies
  • CD40 Ligand