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CD26 up-regulates expression of CD86 on antigen-presenting cells by means of caveolin-1

2004; National Academy of Sciences; Volume: 101; Issue: 39 Linguagem: Inglês

10.1073/pnas.0405266101

1091-6490

Kei Ohnuma, Tadanori Yamochi, Masahiko Uchiyama, Kunika Nishibashi, Noritada Yoshikawa, Noriaki Shimizu, Satoshi Iwata, Hirotoshi Tanaka, Nam H. Dang, Chikao Morimoto,

Caveolin-1 and cellular processes

CD26 is a T cell costimulatory molecule with dipeptidyl peptidase IV activity in its extracellular region. We previously reported that recombinant soluble CD26 enhanced T cell proliferation induced by the recall antigen tetanus toxoid (TT). However, the mechanism involved in this enhancement is not yet elucidated. We now demonstrate that CD26 binds Caveolin-1 on antigen-presenting cells, and that residues 201–211 of CD26 along with the serine catalytic site at residue 630 contribute to binding to caveolin-1 scaffolding domain. In addition, after CD26–caveolin-1 interaction on TT-loaded monocytes, caveolin-1 is phosphorylated, which links to activate NF-κB, followed by up-regulation of CD86. Finally, reduced caveolin-1 expression on monocytes inhibits CD26-mediated CD86 up-regulation and abrogates CD26 effect on TT-induced T cell proliferation. Taken together, these results strongly suggest that CD26–caveolin-1 interaction plays a role in the up-regulation of CD86 on TT-loaded monocytes and subsequent engagement with CD28 on T cells, leading to antigen-specific T cell activation.