A role for CD99 in T cell activation.
The function of the T cell surface protein CD99 was investigated in human CD4(+) peripheral T cells. Crosslinking of the CD99 molecule using anti-CD99 mAbs in the presence of anti-CD3 Ab resulted in a marked enhancement of proliferation. CD99 coligation also enhanced CD25 expression and early markers of T cell activation, CD69 and CD40L. Ligation of CD99 resulted in the pronounced tyrosine phosphorylation of an approximately 29-kDa protein suggesting that a specific CD99-induced signal transduction pathway may exist. Simultaneous costimulation with anti-CD99 and anti-CD28 Abs appeared to have additive effects on CD40L expression while CD99 ligation had no effect on CD2-mediated T cell induction of CD40L expression. These results demonstrate that CD99 signal transduction can deliver effective costimulatory signals to T cells.
Wingett
D
D
Department of Veterans Affairs Medical Center, Boise, Idaho, 83702, USA. denise.wingett.med.va.gov
Forcier
K
K
Nielson
C P
CP
D000071443:12E7 Antigen; D015703:Antigens, CD / Q000502:physiology*; D018801:CD2 Antigens / Q000502:physiology; D018106:CD28 Antigens / Q000502:physiology; D017252:CD3 Complex / Q000276:immunology; D023201:CD40 Ligand; D015815:Cell Adhesion Molecules / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000032:analysis; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology*; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation; D051746:ZAP-70 Protein-Tyrosine Kinase
D000071443:12E7 Antigen; D015703:Antigens, CD; D018801:CD2 Antigens; D018106:CD28 Antigens; D017252:CD3 Complex; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D008562:Membrane Glycoproteins; D023201:CD40 Ligand; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human