Expression and function of 4-1BB during CD4 versus CD8 T cell responses in vivo

✍ Scribed by Wojciech Dawicki; Tania H. Watts

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 334 KB
• Volume: 34
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/eji.200324278

✦ Synopsis

Abstract

4‐1BBL^–/–^ mice have a defect in recall CD8^+^ T cell responses to viruses, whereas CD4^+^ T cell responses to virus are unimpaired in these mice. In contrast, both CD4^+^ and CD8^+^ T cells respond to 4‐1BB ligand (4‐1BBL) in vitro. To clarify the role of 4‐1BB/4‐1BBL in CD4^+^ versus CD8^+^ T cell responses in vivo, wecompared CD4 (OT‐II) and CD8 (OT‐I) TCR transgenic T cells responding to the same antigen in an in vivo adoptive transfer model in 4‐1BBL^+/+^ versus 4‐1BBL^–/–^ mice. Duringprimary and secondary responses, expression of 4‐1BB on in vivo‐activated TCR transgenic T cells was earlier and more transient than previously observed in vitro, correlating withexpression of the early activation antigen CD69 and preceding the transition to the CD44^hi^ state. Although 4‐1BB is expressed early in the primary response, there was no effect of 4‐1BBL deficiency on initial CD8 T cell expansion and only a minor effect on initial CD4 T cell expansion. The major effect of 4‐1BB/4‐1BBL interaction is on the T cell recall response. This is due to effects of 4‐1BBL on maintenance of T cell numbers at the end of the primary response with additional effects of 4‐1BBL on secondary expansion of T cells.