Virus Entry into Animal Cells

Human retroviruses and AIDS 1997

“…Nevertheless, it does result in some conformational changes, since an increase was observed in the exposure of the V2 and V3 loops, as detected by antibody binding , and antibodies from SIVagm infected monkeys, which failed to neutralize virus in vitro, could neuttalize the sCD4-induced enhancement of SIVagm infection (Allan et al, 1990). This is consistent with the suggestion that sCD4 enhancement of STVagm (and presumably of HTV-1 primary isolates and HTV-2) is a form of receptor mediated activation (Allan et al, 1990), analogous to the low-pH activation observed with influenza virus or Semliki Forest virus (Marsh and Helenius, 1989). b) Molecular rearrangements following receptor binding -formation of coiled-coils Both crystallographic and peptide studies with influenza virus have shown that the low pHmediated conformational changes that occur in HA involve the structural transition of a region within the HA2 (TM) protein.…”

Stepwise dismantling of adenovirus 2 during entry into cells

“…The only major losses that we detected were due to shedding of virus particles from the cell surface (about 20%) and to particles that reached the cytosol, but failed to release their DNA (about 40% of originally cell-bound viruses). Unlike many other viruses that enter by endocytosis (see Marsh and Helenius, 1989), less than 5% of the incoming viruses was routed to lysosomes and degraded. This indicated that the escape of the virus from endosomes into the cytosol is a highly efficient process.…”

“…These processes are rather well understood for several enveloped animal viruses that use refined strategies of membrane fusion and uncoating (for reviews see Helenius, 1992;Kielian and Jungerwirth, 1990;Marsh and Helenius, 1989). Some penetrate directly through the plasma membrane while others enter from endosomes (Helenius et al, 1980;Pauza, 1991;Rigaut et al, 1991;Wittels and Spear, 1991).…”

Molecular mechanism of pathogenesis of dengue virus: Entry and fusion with target cell

“…A number of inhibitors that block the productive infection pathway of large groups of viruses have been identified and characterized. In vivo and in vitro systems have been developed for studying the viral integration by membrane fusion (reviewed by Marsh and Heleniust, 1989). The step-by-step itinerary of the entry pathway of certain viruses, such as the Semliki Forest Virus (SFV) is now known (Helenius et al, 1988; Kielian and Helenius, 1986).…”