SARS-CoV-2

SARS-CoV-2 is an enveloped RNA virus that has four main structural proteins including spike (S) glycoprotein, small envelope (E) glycoprotein, membrane (M) glycoprotein, and the nucleocapsid (N) protein. The spike or S glycoprotein is a transmembrane protein that forms homotrimers which protrude from the viral surface and facilitate the binding of envelope viruses to host cells via ACE2-receptors. The nucleocapsid (N protein) is the structural component of the virus necessary for viral RNA transcription and replication. The membrane or M protein plays a role in determining the shape of the virus envelope, helps to stabilize nucleocapsids and promotes the completion of viral assembly. The envelope or E protein is the smallest protein in the SARS-CoV-2 structure, and it plays a role in the production and maturation of this virus.

The pathogenesis of SARS-CoV-2 infection in humans manifests itself as mild symptoms to severe respiratory failure. Elderly patients and those with serious pre-existing diseases (e.g. hypertension, diabetes, obesity, and cardiovascular disease) tend to have more severe outcomes and the highest death rate. The main cause of death is from respiratory failure due to acute respiratory distress syndrome (ARDS) brought on by a rapid and uncontrolled inflammatory signaling cascade called a “cytokine storm”. The initial trigger for the cytokine storm is not yet known but it likely involves the immune system’s detection of a large quantity of viral antigens released by dying cells.