The CD99 signal enhances Fas-mediated apoptosis in the human leukemic cell line, Jurkat.
The CD99 antigen has been implicated in various cellular processes, including apoptosis in T cells. Previously, we reported two monoclonal antibodies that recognize different epitopes of the CD99 molecule, named DN16 and YG32. In this study, we investigated the role of each CD99 epitope in T cell apoptosis. Unlike the DN16 epitope, CD99 ligation via the YG32 epitope failed to induce T cell death. Surprisingly, however, the YG32 signal enhanced Fas-mediated apoptosis in Jurkat T cells. Augmentation of Fas-mediated apoptosis by YG32 ligation was inhibited by treatment with either of the caspase inhibitors z-VAD-fmk or z-IETD-fmk, and YG32 ligation appeared to induce Fas oligomerization. These results suggest that each CD99 epitope plays a distinct role in T cell biology, especially in T cell apoptosis.
Jung
Kyeong Cheon
KC
Department of Pathology, Hallym University College of Medicine, 1 Okchon-dong, Chunchon 200-702, Kangwon-do, South Korea.
Kim
Nam Hyun
NH
Park
Weon Seo
WS
Park
Seong Hoe
SH
Bae
Youngmee
Y
D000071443:12E7 Antigen; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D015703:Antigens, CD / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D002449:Cell Aggregation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D019169:Jurkat Cells; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism; D019014:fas Receptor / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure
D000071443:12E7 Antigen; D000590:Amino Acid Chloromethyl Ketones; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; C061828:CD99 protein, human; D061945:Caspase Inhibitors; D015815:Cell Adhesion Molecules; D004791:Enzyme Inhibitors; D018984:Epitopes, T-Lymphocyte; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D019014:fas Receptor; D020169:Caspases