Abstract
Herpes simplex virus (HSV) can infect a broad host range and cause mild to life threating infections in humans. The surface glycoproteins of HSV are evolutionarily conserved and show an extraordinary ability to bind more than one receptor on the host cell surface. Following attachment, the virus fuses its lipid envelope with the host cell membrane and releases its nucleocapsid along with tegument proteins into the cytosol. With the help of tegument proteins and host cell factors, the nucleocapsid is then docked into the nuclear pore. The viral double stranded DNA is then released into the host cell’s nucleus. Released viral DNA either replicates rapidly (more commonly in non-neuronal cells) or stays latent inside the nucleus (in sensory neurons). The fusion of the viral envelope with host cell membrane is a key step. Blocking this step can prevent entry of HSV into the host cell and the subsequent interactions that ultimately lead to production of viral progeny and cell death or latency. In this review, we have discussed viral entry mechanisms including the pH-independent as well as pH-dependent endocytic entry, cell to cell spread of HSV and use of viral glycoproteins as an antiviral target.
Highlights
Millions of people worldwide are exposed to herpes simplex virus (HSV) (Looker et al, 2015), following the exposure the virus may remain asymptomatic or may cause mild to life threatening complications (Ramchandani et al, 2016)
HSV can be broadly divided into two serotypes: HSV-1 and HSV-2 (Kelly et al, 2009; Fontana et al, 2017) HSV-1 infections are primarily associated with mild to severe symptoms including blisters and inflammation of oral and ocular cells but in some cases, they can progress to more serious illnesses including blindness, hearing impairment, and fatal encephalitis (Koujah et al, 2019; Lobo et al, 2019)
HSV-1 and HSV-2 belong to the family Herpesviridae, all of which have unique four layers: the central double stranded DNA, enclosed by an icosapentahedral capsid, which is surrounded by a group of tegument proteins, which in turn, are encapsulated in a lipid bilayer envelope containing membraneproteins and glycoproteins (Karasneh and Shukla, 2011)
Summary
Millions of people worldwide are exposed to herpes simplex virus (HSV) (Looker et al, 2015), following the exposure the virus may remain asymptomatic or may cause mild to life threatening complications (Ramchandani et al, 2016). The process of membrane fusion, structural and functional details of these four essential viral glycoproteins, and their host cell surface receptors are discussed in detail. Studies that alter cytoplasmic tail domain have shown the importance of this region, as mutations, truncations and insertions in this region affect viral infectivity, especially by enhancing cell fusion (Weed et al, 2017).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have