CD10 (endopeptidase 24.11) is a thymic peptide-degrading enzyme possibly involved in the regulation of thymocyte functions.
Human immature thymocytes express significant levels of the CD10 (endopeptidase 24.11) cell surface antigen. We report here that IOB5, an anti-CD10 mAb, as well as the phorbol ester PMA down-regulate CD10 activity at the surface of human thymocytes. The kinetics of CD10 modulation were drastically different for both effectors, indicating different regulatory mechanisms. We also demonstrated that intact human thymocytes hydrolyze thymopentin and that CD10 significantly participates in this process. Finally, we found that thymopentin and to a lesser extent phosphoramidon, a specific endopeptidase 24.11 inhibitor, induced up-regulation of CD4 and CD8 molecules at the thymocyte cell surface. In view of these results, we suggest that down-regulation of endopeptidase 24.11 at the thymocyte cell surface might reduce its activity toward thymic factors possibly involved in the regulation of thymocyte functions.
Guerin
S
S
Faculté de Médecine, INSERM U364, Nice, France.
Mari
B
B
Belhacene
N
N
Rossi
B
B
Peyron
J F
JF
Auberger
P
P
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017252:CD3 Complex / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens / Q000378:metabolism; D002648:Child; D015536:Down-Regulation; D006020:Glycopeptides / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D015260:Neprilysin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D016305:Thymopentin / Q000378:metabolism* / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D006020:Glycopeptides; D011480:Protease Inhibitors; D015260:Neprilysin; D013755:Tetradecanoylphorbol Acetate; D016305:Thymopentin; C008890:phosphoramidon