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sábado, 19 de junio de 2021

Un agonista de RIG-I de ARN troncal confiere una protección profiláctica y terapéutica contra la infección aguda y crónica del SARS-CoV-2 en ratones

 

Un agonista de RIG-I de ARN troncal confiere una protección profiláctica y terapéutica contra la infección aguda y crónica del SARS-CoV-2 en ratones

Un tipo de ARN artificial (stem-loop RNA) podría frenar la replicación viral y favorecer la eliminación del virus en infecciones crónicas. La pandemia, al menos, nos está trayendo avances científicos muy interesantes (otro que va de ARN)
 
 A stem-loop RNA RIG-I agonist confers prophylactic and therapeutic protection against acute and chronic SARS-CoV-2 infection in mice -Latest preprint by et al shows that a stem-loop RNA RIG-I agonist in mice can
1) Block viral replication and disease when given early after SARS-CoV-2 infection (including VOCs)
2)Eliminate chronic infection in immunodeficient mice 
 
Tianyang Mao, Benjamin Israelow, Carolina Lucas, Chantal B. F. Vogels, Olga Fedorova, Mallery I. Breban, Bridget L. Menasche, Huiping Dong, Melissa Linehan, Yale SARS-CoV-2 Genome Surveillance Initiative, Craig B. Wilen, Marie L. Landry, Nathan D. Grubaugh, Anna M. Pyle, Akiko Iwasaki  https://www.biorxiv.org/content/10.1101/2021.06.16.448754v1?fbclid=IwAR0eHVid5-HWTYxaj_D5-3DzLGsCWwk5j5pCp0h88QelnCjZPmJluhBEPts
 
 
 
 
We urgently need antiviral agents that can work against any viral threats. Here, we use a stem-loop RNA developed by @AnnaPyle
to trigger interferon to stimulate antiviral state. Work by @MelissaLV14 et al demonstrated robust ISG induction in mice https://advances.sciencemag.org/content/4/2/e1701854
First, we wanted to know if SLR can be used as a post-exposure prophylaxis. Mice infected with lethal dose of SARS-CoV-2 were treated with SLR 4 hours after exposure. SLR-treated mice had no detectable infectious virus 5 days later and most survived
Next, we asked whether interferon signaling is required for the SLR-mediated protection. Mice injected with blocking antibodies to IFNAR were no longer protected by SLR from SARS-CoV-2 infection. Thus, SLR-mediated protection depends on IFN-I signaling
How late can we administer SLR to observe protection? Compared to robust protection at 4 hours, injection of SLR 24 h and 48 h post exposure protected only partially, and at 72 h, no protection was observed. (Note: mouse disease course is accelerated compared to humans) Prof. Akiko Iwasaki
We also tested SLR in a mouse model of immunodeficiency. Here, we used RAG-deficient mice (devoid of T or B cells) that become persistently infected. In immunocompromised patients, prolonged SARS-CoV-2 infection has been widely reported
What is remarkable is that a single injection of SLR in persistently infected animal was able to eliminate infectious virus in most of the treated mice. Thus, in the absence of adaptive immunity, robust IFN response is sufficient to eliminate persistent virus infection
Is SLR effective against the VOCs? SLR injection 4 hours post exposure with P.1, B.1.526, B.1.351 or B.1.1.7 led to significant protection from disease & death. Difference in effectiveness might reflect the IFN-resistance of these variants.  
 
https://www.biorxiv.org/content/10.1101/2021.03.20.436257v1.full
     
 
 
 

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