11/18/2023 0 Comments Coronavirus spike protein![]() Although the outbreaks of SARS seem to be over, SARS is still a safety concern because of the possible reintroduction of a SL-CoV into humans and the risk of an escape of SARS-CoV from laboratories 15, 16. Since then, no new case of SARS has been reported, possibly because of continued global vigilance and surveillance and laboratory bio-safety practices, as well as the euthanizing or quarantining of animals that may have been exposed to SARS-CoV 13, 14. The most recent epidemic of SARS occurred in Beijing and Anhui in China in April 2004 and originated from laboratory contamination ( WHO update 7 see Further information). Four sporadic SARS cases caused by different SARS-CoV isolates than those that predominated in the 2002–2003 outbreak were reported in late 2003 and early 2004 (refs 10, 11, 12). The global outbreak of SARS was brought under control in July 2003 by effective quarantine, patient-isolation and travel restrictions. The overall fatality of SARS is about 10% in the general population, but >50% in patients aged 65 years and older ( WHO update 49 see Further information). Virions are then released from the cell through exocytosis.Īfter its first occurrence, SARS rapidly spread around the world along international air-travel routes, reaching all five continents and 29 countries, resulting in 8,098 cases and 774 deaths by 23 September 2003 (ref. Viral nucleocapsids are assembled from genomic RNA and N protein in the cytoplasm, followed by budding into the lumen of the ERGIC (endoplasmic reticulum (ER)–Golgi intermediate compartment) 128. The full-length negative-strand template is made as a template for genomic RNA. Subgenomic negative-strand templates are synthesized from discontinuous transcription on the plus-strand genome and serve as templates for mRNA synthesis. The viral genome is released and translated into viral replicase polyproteins pp1a and 1ab, which are then cleaved into small products by viral proteinases. S protein first binds to the cellular receptor angiotensin-converting enzyme 2 (ACE2) 129, and the ACE2–virus complex is then translocated to endosomes, where S protein is cleaved by the endosomal acid proteases (cathepsin L) 105 to activate its fusion activity. Severe acute respiratory syndrome-coronavirus (SARS-CoV) enters target cells through an endosomal pathway 113, 121, 125, 126, 127. ![]() A further understanding of the life cycle and pathogenesis of SARS-CoV will help us to develop vaccines and therapeutics to prevent and treat SARS-CoV and SARS-like coronavirus (SL-CoV) infections in the future. SARS-CoV can infect and replicate in several cell types in the human body and causes serious pathological changes ( Box 1, Fig 1). SARS-CoV, a zoonotic virus, resides in hosts that form its natural reservoir, such as bats, but can also infect intermediate hosts, such as small animals (for example, palm civets), before being transmitted to humans 6, 7, 8. Its genome RNA encodes a non-structural replicase polyprotein and structural proteins, including spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins 3, 4, 5. SARS-CoV is an enveloped, single and positive-stranded RNA virus 2. ![]() A global effort coordinated by WHO led to the identification, in April 2003, of a new coronavirus, SARS-coronavirus ( SARS-CoV), as the agent that caused the outbreak 2. This acute, and often severe, respiratory illness originated in the Guangdong province of China in November 2002 (ref. Severe acute respiratory syndrome (SARS) was the first new infectious disease identified in the twenty-first century. The work on SARS-CoV S protein-based vaccines and drugs will be useful as a model for the development of prophylactic strategies and therapies against other viruses with class I fusion proteins that can cause emerging infectious diseases. Peptides, antibodies, organic compounds and short interfering RNAs are additional anti-SARS-CoV therapeutics that target the S protein. These vaccines are based on SARS-CoV full-length S protein and its receptor-binding domain, including DNA-, viral vector- and subunit-based vaccines SARS S protein is the target of new SARS vaccines. SARS-CoV S protein induces humoral and cellular immune responses against SARS-CoV. SARS-CoV S protein mediates binding of the virus with its receptor angiotensin-converting enzyme 2 and promotes the fusion between the viral and host cell membranes and virus entry into the host cell. SARS is a newly emerging infectious disease, caused by SARS-CoV, a novel coronavirus that caused a global outbreak of SARS. This Review provides an overview on the spike (S) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) as a target for the development of vaccines and therapeutics for the prevention and treatment of SARS. ![]()
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