title: Antibody blockade of Thy-1 (CD90) impairs mouse cytotoxic T lymphocyte induction by anti-CD3 monoclonal antibody.
abstract: Thy-1 (CD90) expressed by mouse T cells is known to have signal transducing properties, but the ability of Thy-1 to enhance cytotoxic T lymphocyte (CTL) development is not well understood. Here we show that stimulation of mouse T cells with monoclonal antibodies (mAb) to CD3, CD28 and Thy-1 (clone G7), which were coimmobilized on polystyrene microbeads, resulted in a greater proliferative response than stimulation with only anti-CD3 and anti-CD28 mAb, indicating that Thy-1 cross-linking enhanced T cell receptor/CD28-driven T cell activation. Consistent with this finding, Thy-1 blockade with a soluble nonactivating anti-Thy-1 mAb (clone 30-H12) inhibited anti-CD3-induced proliferation of CD4+ and CD8+ T cells, and the induction of cytotoxic effector cells in a dose-dependent fashion. Interleukin-2 synthesis and CD25 expression were also impaired by Thy-1 blockade. The inhibitory effect involved a defect at or before the level of protein kinase C activation because the addition of phorbol ester ablated the anti-Thy-1-mediated inhibition of anti-CD3-induced T cell activation. The CTL that were induced in the presence of blocking anti-Thy-1 mAb adhered to target cells but showed reduced expression of granzyme B and perforin. In contrast, Fas ligand expression and function was not affected by Thy-1 blockade. We conclude that Thy-1 signalling promotes the in vitro generation of CTL that kill in a granule-dependent fashion.
authors: Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Canada.
authors: S M Mansour
authors: SM
authors: Haeryfar
authors: David M
authors: DM
authors: Conrad
authors: Brucel
authors: B
authors: Musgrave
authors: David W
authors: DW
authors: Hoskin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D000943:Antigens, Differentiation / Q000235:genetics; D017252:CD3 Complex / Q000276:immunology*; D049109:Cell Proliferation / Q000187:drug effects; D010450:Endopeptidases / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D053804:Granzymes; D007376:Interleukin-2 / Q000235:genetics / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D052899:Pore Forming Cytotoxic Proteins; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D018800:Thy-1 Antigens / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D017252:CD3 Complex; D007376:Interleukin-2; D008565:Membrane Proteins; D052899:Pore Forming Cytotoxic Proteins; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D018800:Thy-1 Antigens; C483886:perforin, mouse; D011493:Protein Kinase C; D010450:Endopeptidases; D053804:Granzymes; C509214:Gzmb protein, mouse