. . . . . . . . . . . . . . "HIV-1 Tat inhibits the enzymatic activity of CD26, thereby suppressing DNA synthesis and IL-1 beta production, stimulating secretion of IL-1 receptor antagonist and TNF-alpha, and causing, at least in part, the immunosuppressive effects of Tat" . "The N-terminal nine amino acids of HIV-1 Tat mediate the binding of Tat to CD26" . "HIV-1 Tat induces tyrosine phosphorylation of DPPIV in Tat/DPPIV-coexpressing cells" . "HIV1-Tat co-localizes and coimmunoprecipitates with human Dipeptidyl peptidase IV (DPPIV) protein" . "inhibits" . "induces phosphorylation of" . "co-localizes with" . "binds" .