Cell Rep: Key viral factors affect immunity in COVID19 patients.

March 20, 2020 // --- As of October 2020, SARS-CoV-2 has led to an ongoing pandemic, with more than 35 million reported cases and more than 1 million deaths worldwide.
a prominent feature of the immune response that distinguishes COVID-19 from SARS compared to SARS-CoV and influenza A viruses is that SARS-CoV-2 has a poor induction effect on type I interferon (IFN).
note that the damaged IFN response is associated with COVID-19 disease.
, however, the molecular mechanism of inefficient IFN reactions in SARS-CoV-2 infections is not clear.
team at the Institute of Medical Sciences (IMSUT) at the University of Tokyo aimed to identify the viral factors that determine immune activation after SARS-CoV-2 infection and found that the gene ORF3b, encoded by SARS-CoV-2, was an effective IFN antagonist.
, chief scientist at www.pixabay.com and associate professor of systems virology at the Department of Infectious Disease Control, said: "The adverse IFN response in PATIENTS of COVID-19 may be due to the effects of orF3b, the product of the virus.
"Although SARS-CoV infection can cause acute and severe pneumonia, SARS-CoV-2 infections can be asymptomatic or cause flu-like symptoms such as fever, cough and fatigue.
, the marker of SARS-CoV-2 infection, COVID-19, is an undesirable inducement of type I interferon (IFN) compared to SARS-CoV and influenza A virus infections.
note that the damaged IFN response is related to the severity of COVID-19.
, however, the molecular mechanism of inefficient IFN reactions in SARS-CoV-2 infections is not clear.
comparing the genetic sequences of sars-CoV-2 encoded genes with SARS-CoV, the team found that the gene length of SARS-CoV-2 ORF3b was significantly shorter than that of SARS-CoV ORF3b.
Because ORF3b of SARS-CoV is known as an anti-IFN viral antagonist, they hypothesically assume that the difference in the length of the ORF3b gene between SARS-CoV-2 and SARS-CoV may alter its anti-IFN activity and may further explain this difference.
symptoms of both viral infections.
, SARS-CoV-2 ORF3b is a more effective IFN antagonist than SARS-CoV ORF3b.
system development analysis and functional analysis showed that SARS-CoV-2-related viruses in bats and rollers also encoded shorter ORF3b gene products with strong anti-IFN activity.
the characterization of natural SARS-CoV-2 ORF3b variants with enhanced anti-IFN activity, the authors' analysis of approximately 17,000 SARS-CoV-2 sequences identified a natural variation in which a longer ORF3b reading box was reconstructed.
variant inhibits IFN more effectively than ORF3b of the parent SARS-CoV-2 strain.
, it is important to continue monitoring the virus sequence to see if new ORF3b mutations occur during the current pandemic.
(bioon.com) Source: Identifi of a viral factor that impairs immunes responses in COVID-19 patients Original source: Yoriyuki Konno, Izumi Kimura, Keiya Uriu, Masaya Fukushi, Takashi Irie, Yoshio Koyanagi, Daniel Sauter, Robert J. Gifford, Kei Soga, Kei Sato. SARS-CoV-2 ORF3b Is a Potent Interferon Antagonist Whose Activity Is Increased by a Naturally Moveding Elongation Variant. Cell Reports, 2020; 32 (12): 108185 DOI: 10.1016/j.celrep.2020.108185.