Hiv Replication In Cd4(+) T Lymphocytes In The Presence And Absence Of Follicular Dendritic Cells: Inhibition Of Replication Mediated By Alpha-1-Antitrypsin Through Altered I Kappa B Alpha Ubiquitination

Follicular dendritic cells (FDCs) increase HIV replication and virus production in lymphocytes by increasing the activation of NF-kappa B in infected cells. Because alpha-1-antitrypsin (AAT) decreases HIV replication in PBMCs and monocytic cells and decreases NF-kappa B activity, we postulated that AAT might also block FDC-mediated HIV replication. Primary CD4(+) T cells were infected with HIV and cultured with FDCs or their supernatant with or without AAT, and ensuing viral RNA and p24 production were monitored. NF-kappa B activation in the infected cells was also assessed. Virus production was increased in the presence of FDC supernatant, but the addition of AAT at concentrations >0.5 mg/ml inhibited virus replication. AAT blocked the nuclear translocation of NF-kappa B p50/p65 despite an unexpected elevation in associated phosphorylated and ubiquitinated I kappa B alpha (Ub-I kappa B alpha). In the presence of AAT, degradation of cytoplasmic I kappa B alpha was dramatically inhibited compared with control cultures. AAT did not inhibit the proteasome; however, it altered the pattern of ubiquitination of I kappa B alpha. AAT decreased I kappa B alpha polyubiquitination linked through ubiquitin lysine residue 48 and increased ubiquitination linked through lysine residue 63. Moreover, lysine reside 63-linked Ub-I kappa B alpha degradation was substantially slower than lysine residue 48-linked Ub-I kappa B alpha in the presence of AAT, correlating altered ubiquitination with a prolonged I kappa B alpha t(1/2). Because AAT is naturally occurring and available clinically, examination of its use as an inhibitory agent in HIV-infected subjects may be informative and lead to the development of similar agents that inhibit HIV replication using a novel mechanism. The Journal of Immunology, 2011, 186: 3148-3155.