4-1BB is an inducible receptor-like protein expressed in both cytolytic and Th cells. Optimal induction of 4-1 BB mRNA in T cells required both PMA and ionomycin stimulation, indicating that protein kinase C activation and increases in intracellular Ca2+ were required for its expression. 4-1 BB was categorized as an early activation gene since the protein synthesis inhibitor, cycloheximide, blocked the induction of 4-1 BB mRNA. A rat mAb, 53A2, was generated against recombinant soluble 4-1 BB and was used to characterize this molecule. 4-1 BB is a 30-kDa glycoprotein and appears to exist as both a monomer and a 55-kDa dimer on the cell surface of a T cell clone. The 4-1 BB protein may be post-translationally modified since its predicted backbone is 25 kDa. FACS analysis indicated that 4-1 BB was inducible and expressed on the cell surface of activated splenic T cells and thymocytes. Cross-linking of 4-1BB on anti-CD3-stimulated T cells with 53A2 resulted in a dramatic enhancement of T cell proliferation. This suggests that 4-1BB may function as an accessory signaling molecule during T cell activation. Journal of Immunology, 1993, 150: 771.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1993|
ASJC Scopus subject areas
- Immunology and Allergy