Elevated apoptosis of peripheral T lymphocytes in diabetic BB rats

Immunology. 1999 Dec;98(4):590-4. doi: 10.1046/j.1365-2567.1999.00907.x.

Abstract

Thymocytes and peripheral lymphocytes of BioBreeding (BB) diabetes-prone (BBDP) and diabetes-resistant (BBDR) rat were analysed by fluorescence-activated cell sorter (FACS). The number of CD4- CD8-, CD4+ CD8-, CD4- CD8+ and CD4+ CD8+ subsets was not different between BBDP and BBDR rat thymocytes, whereas spleen and lymph nodes in BBDP rats undergo severe T-cell lymphopenia. Notably, mature CD4- CD8+ [T-cell receptor (TCR)-alphabeta+ and CD5+] cells are certainly present in the BBDP rat thymus, unlike some previous reports, suggesting that the differentiation of CD4- CD8+ from CD4+ CD8+ cells occurs normally in the BBDP rat thymus. As a cause of peripheral T-cell lymphopenia we suspected apoptosis of recent thymic emigrants. By FACS analysis with fluorescein isothiocyanate-labelled annexin V, elevated apoptosis was evident in BBDP rat peripheral lymphocytes. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) staining in BBDP rat splenic sections revealed that a number of TUNEL-positive cells were observed in the T-lymphocyte-rich area. From these results, we postulate that an abnormally elevated apoptosis of peripheral T lymphocytes, but not impaired thymocyte differentiation, is a cause of the peripheral T-cell lymphopenia in BBDP rats.

MeSH terms

  • Animals
  • Apoptosis*
  • CD8-Positive T-Lymphocytes / physiology
  • Cell Differentiation
  • Diabetes Mellitus, Type 1 / immunology*
  • Flow Cytometry
  • In Situ Nick-End Labeling
  • Lymph Nodes / immunology
  • Lymphoid Tissue / physiopathology*
  • Rats
  • Rats, Inbred BB / immunology*
  • Spleen / immunology
  • T-Lymphocytes / physiology*