Characterization of CD4+ T cells in mouse bone marrow. I. Increased activated/memory phenotype and altered TCR Vbeta repertoire

Eur J Immunol. 1999 Mar;29(3):1051-6. doi: 10.1002/(SICI)1521-4141(199903)29:03<1051::AID-IMMU1051>3.0.CO;2-Y.

Abstract

A significant proportion of memory B cells home to bone marrow (BM) which is a major site of anamnestic antibody responses in mice. We hypothesized that memory T cells likewise accumulate in BM perhaps to provide help for antibody production, and that the compartment of CD4+ T cells in BM of unimmunized mice would be enriched for memory phenotype cells that might have been activated by environmental antigens. The phenotype of activated/memory CD4+ lymphocytes has been defined as CD44hi CD45RBlo CD62L-. Conversely, the phenotype of immunologically naive cells is CD44lo CD45RBhi CD62L+. Flow cytrometric analysis of tissue from normal, adult C57BL/6 mice identified 1-2 % CD3+CD4+ cells in BM. Up to 40 % of CD3+CD4+ cells in the BM expressed the activated/memory phenotype compared with < or = 10% in the spleen and lymph nodes. Analysis of TCR Vbeta repertoire revealed that expression of Vbeta3 and Vbeta7 genes was increased as much as fourfold in BM compared to the periphery; most of this increase was within the CD44hi T cells. The accumulation of activated/memory T cells and clonotypic expansion(s) was not seen in the BM of germ-free mice, indicating that it reflects the history of the animal's exposure to antigens. Finally, immunization of mice which express a transgenic T cell receptor specific for ovalbumin peptide resulted in appearance of antigen-specific T cells with activated/memory phenotype in the BM.

Publication types

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

MeSH terms

  • Animals
  • Bone Marrow Cells / classification
  • Bone Marrow Cells / immunology*
  • CD4-Positive T-Lymphocytes / classification
  • CD4-Positive T-Lymphocytes / immunology*
  • Female
  • Immunoglobulin Variable Region / immunology*
  • Immunologic Memory*
  • Immunophenotyping
  • Lymphocyte Activation / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Receptors, Antigen, T-Cell, alpha-beta / immunology*

Substances

  • Immunoglobulin Variable Region
  • Receptors, Antigen, T-Cell, alpha-beta