In vivo proliferation of rat lamina propria T lymphocytes: general hyporesponsiveness but increased importance of the CD2 and CD28 pathways.

Lamina propria T lymphocytes (LPL-T) have a low proliferative potential in vitro. We asked whether LPL-T are also hyporesponsive in vivo and whether this is specific for the alphabeta T cell receptor (TCR). Mitogenic mAb directed at the alphabeta TCR, CD2, CD28, or control mAbs plus IL-2 were injected into rats. Proliferation and/or apoptosis were detected by double staining using 5-bromo-2'-deoxyuridine/TUNEL and the alphabeta TCR. LPL-T were hyporesponsive to various stimuli compared to other T cells. The strongest proliferation was found upon CD2/CD28 stimulation (LPL-T: 281 +/- 6%; spleen: 642 +/- 31%). LPL-T proliferation was only detectable at 24 h while proliferation in other compartments also occurred later. Hyporesponsiveness was not caused by enhanced T cell apoptosis upon alphabeta TCR stimulation. In conclusion, stimulation of LPL-T results in much shorter and weaker in vivo proliferation than in other lymphoid organs. Overall, CD2/CD28 costimulation is the strongest T cell stimulus in vivo.

Lumbar artery aneurysm.

The purpose of this report is to present a rare case of lumbar artery aneurysm. We report the case of a 54-years-old male patient who was misdiagnosed over years having a chronic infrarenal aortic aneurysm. A 64-slice CT at our institution revealed a large lumbar artery aneurysm. The conclusion of this case report is that a lumbar or accessory renal artery aneurysm has to be taken into consideration if there is a localized enlargement of the lower abdominal aorta and a high resolution CT-scan is strongly recommended to make the exact diagnosis.

Role of T lymphocytes in rat 2,4,6-trinitrobenzene sulphonic acid (TNBS) induced colitis: increased mortality after gammadelta T cell depletion and no effect of alphabeta T cell depletion.

BACKGROUND AND AIM: Indirect evidence suggests that CD4+ T cells have a pathogenic while gammadelta T cells have a protective role in the initiation and perpetuation of inflammatory bowel disease. To define the role of T cell subsets in a rat colitis model (2,4,6-trinitrobenzene sulphonic acid (TNBS)) we analysed colitis severity after effective depletion of T helper cells, alphabeta T cells, or gammadelta T cells. METHODS: T helper cells, alphabeta T cells, or gammadelta T cells were depleted using previously described monoclonal antibodies directed at the CD4 molecule (OX38), the CD2 molecule (OX34, both depleting CD4+ T cells), the alphabeta T cell receptor (R73), and the gammadelta T cell receptor (V65). Depletion was verified by flow cytometry and/or immunohistology. Colitis was induced using intracolonic application of TNBS. RESULTS: Surprisingly, depletion of T helper cells or alphabeta T cells had no influence on survival, macroscopic or microscopic scores, or myeloperoxidase activity following colitis induction. In contrast, depletion of gammadelta T cells resulted in significantly increased mortality (V65: 73%, n=15) compared with controls (30%, n=13; p<0.03). In addition, colitis was histologically more severe in the gammadelta T cell depleted group compared with controls (p<0.05). CONCLUSIONS: T helper cells or alphabeta T cells did not influence the initiation or perpetuation of rat TNBS colitis. In contrast, gammadelta T cells had a protective role in rat TNBS colitis as depletion caused increased mortality.