CD4 and HIV infectious disease: HIV is able to induce IRF-1 early upon infection, before the expression of Tat, and it is possible that it plays an important role in the early phases of HIV infection and as a strategy to counteract IFN-mediated host defenses [124, review in 125] On the other hand, IRF-8 represses IRF-1-Tat-mediated transactivation of the LTR by interfering with IRF-1-Tat association, and it inhibits HIV-1 replication in CD4+ cells [96, 99].