How SARS-CoV-۲ (causative agent of COVID-۱۹) outsmarts the host immune system

Undoubtedly, the most succession of SARS-CoV-۲ in creating a pandemic and persistent infection is related to how it outsmarts the host immune system. In the present study, the various strategies used by the virus to escape the host's immune system have been reviewed. The ability to infect cells of various tissues and organs such as the lungs, small intestine, and liver is one of the successes of the virus in causing persistent infection, which ultimately leads to an increase in viral load in the host and challenging the immune system to combat with it. This ability is related to Furin, an enzyme that is involved in the activation of SARS-CoV-۲ during entrance into the cells and expressed by cells of various organs. Like other coronaviruses, during SARS-CoV-۲ infection, double-stranded RNAs from genome replication and RNA synthesis become inaccessible to cytosolic PRRs (pattern recognition receptors) of the immune system such as RIG-I, MDA۵, and TLR۳ by being placed inside the double-membrane vesicles. SARS-CoV-۲, like other coronaviruses, can escape from the immune system by inhibiting or delaying the production of interferon. In persistent infection, successive mutations in the virus, especially in the spike protein, can protect the virus against humoral immunity. High genetic variability also leads to inefficiency of the immune system in recognizing and neutralizing the virus in subsequent encounters. Coinfection of the host with two different strains can lead to the emergence of a new strain with new capabilities by genomic recombination between these two strains. Ultimately, the virus’s ability to infect different host species (humans and other animals) is most likely very effective in the wide range and stability of the outbreak. In conclusion, to combat the virus and design a vaccine, it is important to consider the significant ability of SARS-CoV-۲ to cause infection and escape the immune system.

کلیدواژه ها:

Coronavirus ، Escape ، Immune system