APOPTOSIS OF MATURE T CELLS (MEETING ABSTRACT)

Important note: Information in this article was accurate in 1992. The state of the art may have changed since the publication date.

APOPTOSIS OF MATURE T CELLS (MEETING ABSTRACT)

Fifteenth Symposium of the International Association for Comparative Research on Leukemia and Related Diseases. October 6-11, 1991, Padova/Venice, Italy, p. 23, 1991.. Unique Identifier : AIDSLINE ICDB/92682379
Facchinetti A; Panozzo M; Pertile P; Biasi G; Inst. of Oncology, Univ. of Padova, Padova, Italy

Abstract: Superantigen binding (SEB) to MHC class II molecules, and to mature T cells bearing receptors encoded by specific V beta gene segments, induces strong proliferative responses in vitro. Nevertheless, in vivo exposure to Mlsa or SEB can lead in a few weeks to specific tolerance in the mature T-cell compartment through a clonal deletion mechanism due to the activation of a programmed cell death process (PCD). We examined whether different signals throughout a beta TCR could induce the elimination of T lymphocytes preactivated by SEB. Groups of SEB-injected BALB/c mice were treated in vivo a few days later with a non-T-cell-depleting anti-CD4 Mab (H129.19) or an anti-V beta 8 TCR mAB; cytofluorimetric analysis of the lymph node T-cell repertoire disclosed a prompt selective loss of CD4+ V beta 8+ and V beta 8+ T cells, respectively, in these mice. Similarly, in vitro exposure of SEB-activated T cells to insolubilized V beta 8 TCR mAB induced clonal elimination of V beta 8+ T cells and PCD, as revealed by Southern blot analysis of DNA fragmentation. Other studies showed that PCD, the major mechanism involved in intrathymic T-cell-negative selection, also occurs naturally in mature T-lymph node cells. We advance that apoptosis in peripheral lymphoid organs might reflect the physiological elimination of mature T cells activated by endogenous superantigens recognizing self or exogenous antigens. If this is the case, the same process could also bring about an undesired shaping of the T-cell repertoire, leading to inefficacious immune responses to (tumor) antigens persistently expressed in the host.

Keywords: Animal Antibodies, Monoclonal/IMMUNOLOGY Antigens, Neoplasm/*IMMUNOLOGY Cell Death Cell Division CD4-CD8 Ratio Histocompatibility Antigens Class II/IMMUNOLOGY Lymphocyte Transformation Mice Mice, Inbred BALB C Receptors, Antigen, T-Cell, alpha-beta/IMMUNOLOGY T-Lymphocytes/CYTOLOGY/*IMMUNOLOGY ABSTRACT
920930
M9290920

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