Characterization of anti-HIV activity mediated by HIV-1 integrase C-terminal domain polypeptides expressed in susceptible cells

Human immunodeficiency virus type 1 (HIV-1) integrase (IN) is not only a key molecule for HIV genomic integration but also is important in other steps of HIV-1 replication, including reverse transcription, nuclear import, chromatin targeting, virus release and maturation. In this study, we investigated whether expression of the HIV-1 IN C-terminal domain (CTD) polypeptide could affect viral replication. We found that expression of T7 or YFP tagged INc_{wild type (WT)} and mutant INc_{215, 9AA} in virus-producing cells decreased HIV-1 infectivity roughly 3-7 fold in HeLa-β-Gal- CD4/CCR5, CD4⁺MT4 and C8166 T cells. We further observed that the Pr55^gag processing in progeny viruses produced from cells expressing the T7-INc_WT or T7-INc_{215, 9AA} was largely inhibited. Results from one-cycle HIV-1 replication revealed that the expression of the IN CTD lead to a moderate inhibition of incoming virus infection by affecting the events prior to integration. By using a lentiviral vector system, we generated a stable CD4⁺ C8166 T cell line expressing either T7-INc_WT or T7-INc_{215, 9AA} and demonstrated that both cell lines became resistant to HIV-1 infection. We conclude that the expression of the HIV-1 IN CTD polypeptide alone can inhibit virus replication by impairing virus maturation and interfering with early step(s) of the viral life cycle.