Ghezzi S.,Viral Pathogens and Biosafety Unit |
Pacciarini F.,AIDS Immunopathogenesis Unit |
Nozza S.,Transplantation and Infectious Diseases |
Racca S.,San Raffaele Scientific Institute |
And 8 more authors.
Objective: To investigate the impact of intermittent interleukin-2 (IL-2) plus combination antiretroviral therapy (cART) on HIV-1 entry co-receptor use. Methods: Primary HIV-1 isolates were obtained from 54 HIV-1-positive individuals at baseline and after 12 months using co-cultivation of peripheral blood mononuclear cells (PBMC) with activated PBMC of HIV-negative healthy donors. HIV-1 co-receptor use was determined on U87-CD4 cells. Results: Fourteen out of the 21 (67%) IL-2-treated individuals harbouring a primary CCR5-dependent (R5) HIV-1 isolate at baseline confirmed an R5 virus isolation after 12 months in contrast to 3 out of 7 (43%) of those receiving cART only. After 12 months, only 1 R5X4 HIV-1 isolate was obtained from 21 cART+IL-2-treated individuals infected with an R5 virus at entry (5%) vs. 2/7 (29%) patients receiving cART alone, as confirmed by a 5-year follow-up on some individuals. Conclusions: Intermittent IL-2 administration plus cART may prevent evolution towards CXCR4 usage in individuals infected with R5 HIV-1. © 2009 British HIV Association. Source
Sannino S.,Transplantation and Infectious Diseases |
Sannino S.,University of Milan |
Anelli T.,Transplantation and Infectious Diseases |
Anelli T.,Vita-Salute San Raffaele University |
And 10 more authors.
Journal of Cell Science
ERp44 is a pH-regulated chaperone of the secretory pathway. In the acidic milieu of the Golgi, its C-terminal tail changes conformation, simultaneously exposing the substrate-binding site for cargo capture and the RDEL motif for ER retrieval through interactions with cognate receptors. Protonation of cysteine 29 in the active site allows tail movements in vitro and in vivo. Here, we show that conserved histidine residues in the C-terminal tail also regulate ERp44 in vivo. Mutants lacking these histidine residues retain substrates more efficiently. Surprisingly, they are also Oglycosylated and partially secreted. Co-expression of client proteins prevents secretion of the histidine mutants, forcing tail opening and RDEL accessibility. Client-induced RDEL exposure allows retrieval of proteins from distinct stations along the secretory pathway, as indicated by the changes in O-glycosylation patterns upon overexpression of different partners. The ensuing gradients might help to optimize folding and assembly of different cargoes. Endogenous ERp44 is O-glycosylated and secreted by human primary endometrial cells, suggesting possible pathophysiological roles of these processes. © 2014. Published by The Company of Biologists Ltd. Source