Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The characterization of restrictions to lentivirus replication in cells identifies critical steps in the viral life cycle and potential therapeutic targets. We previously reported that a human immunodeficiency virus type 2 (HIV-2) isolate was restricted to infection in some human cells, which led us to identify a step in the life cycle of HIV-2 detected after reverse transcription but prior to nuclear entry. The block is bypassed with a vesicular stomatitis virus glycoprotein G (VSV-G) envelope (A. McKnight et al., J. Virol. 75:6914-6922, 2001). We hypothesized that, although the restriction is apparent at a post-reverse transcription step, the lack of progress results from a failure of the virus to reach a cellular compartment with access to the nucleus. Here we analyzed molecular clones of the restricted virus, MCR, and an unrestricted virus, MCN. Using sequence analysis and gene swapping, we mapped the viral determinants to gag and env. Site-directed mutagenesis identified a single amino acid at position 207 in CA to be responsible for the gag restriction. Pseudotype experiments indicate that this step is also important for the infection of cells by HIV-1. The HIV-1 NL4.3 core is restricted if supplied with a restricted MCR envelope but not with VSV-G. Also the NL4.3 envelope rescues the restricted core of HIV-2 MCR. Abrogation experiments with MLV demonstrate that the restriction is distinct from Fv1/Ref1/Lv1. We propose that this represents a new lentiviral restriction, Lv2. Thus, the envelope and capsid of HIV act to ensure that the virus is delivered into an appropriate cellular compartment that allows postentry events in viral replication to proceed efficiently.
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PMID:Lv2, a novel postentry restriction, is mediated by both capsid and envelope. 1474 65

The infection of cultured monocyte-derived dendritic cells (DCs) with HIV-1 involves CD4 and CCR5 receptors, while transmission to T cells is enhanced at least in part by the lectin DC-SIGN/CD209. In the present study, we studied BDCA-1+ myeloid DCs isolated directly from human blood. These cells express CD4 and low levels of CCR5 and CXCR4 coreceptors, but not DC-SIGN. The myeloid DCs replicate two R5 viruses, BaL and YU2, and transfer infection to activated T cells. The virus productively infects a small fraction of the blood DCs that fail to mature in culture, as indicated by the maturation markers CD83 and DC-LAMP/CD208, and the expression of high CD86 and MHC class II, in contrast to many noninfected DCs. A greater proportion of BDCA-1+ DCs are infected when the virus is pseudotyped with the vesicular stomatitis envelope VSV-G (5-15%), as compared with the R5 virus (0.3-3.5%), indicating that HIV-1 coreceptors may limit the susceptibility of DCs to become infected, or the endocytic route of viral entry used by HIV/vesicular stomatitis virus enhances infectivity. When infected and noninfected cells are purified by cell sorting, the former uniformly express HIV p24 gag and are virtually inactive as stimulators of the allogeneic MLR, in contrast to potent stimulation by noninfected DCs from the same cultures. These results point to two roles for a small fraction of blood DCs in HIV-1 pathogenesis: to support productive infection and to evade the direct induction of T cell-mediated immunity.
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PMID:HIV-1 selectively infects a subset of nonmaturing BDCA1-positive dendritic cells in human blood. 1639 85