Elevated apoptosis of peripheral T lymphocytes in diabetic BB rats.
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.
Jung
C G
CG
Center for Experimental Animal Science, Nagoya City University Medical School, Nagoya, Japan.
Kamiyama
T
T
Agui
T
T
D000818:Animals; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology; D002454:Cell Differentiation; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005434:Flow Cytometry; D020287:In Situ Nick-End Labeling; D008198:Lymph Nodes / Q000276:immunology; D008221:Lymphoid Tissue / Q000503:physiopathology*; D051381:Rats; D011913:Rats, Inbred BB / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000502:physiology*