Exp Mol Med.  2007 Apr;39(2):176-184.

CD99 activates T cells via a costimulatory function that promotes raft association of TCR complex and tyrosine phosphorylation of TCR zeta

• Oh KI
• Kim BK
• Ban YL
• Choi EY
• Jung KC
• Lee IS
• Park SH

Abstract

We investigated the co-stimulatory role of a cell-surface protein, CD99. Co-ligation of CD99 and suboptimal CD3 induced T-cell activation to a level comparable to that obtained with optimal CD3 or CD3+CD28. We also noted concomitant enhancement of the earliest T-cell receptor (TCR) signaling events. In addition, co-ligation of CD99 and CD3 led to translocation of TCR complexes into the lipid raft, without concomitant migration of CD99 to the raft, and consequent enhancement of TCR zeta-mediated signal 1. These data demonstrate the unique properties of CD99 co-stimulation that distinguish this molecule from CD28 and other raft-resident co-stimulatory factors.

Keyword

antigens; lymphocyte activation; receptors, antigen, T-cell; signal transduction; T lymphocytes

MeSH Terms

Antigens, CD/*immunology
Antigens, CD3/immunology
Cell Adhesion Molecules/*immunology
Down-Regulation
Humans
Jurkat Cells
Lymphocyte Activation/*immunology
Membrane Microdomains/*immunology
Membrane Proteins/*immunology
Phosphorylation
Phosphotyrosine/*metabolism
Protein Transport
Receptors, Antigen, T-Cell/*immunology
T-Lymphocytes/*immunology