A team at the Ohio State University has found that Covid virus has adopted a stealth move.... spreading through cell-to-cell transmission.
"Significance
It is currently unknown if SARS-CoV-2 can spread through cell–cell contacts, and if so, the underlying mechanisms and implications. In this work, we show, by using lentiviral pseudotyped virus, that the spike protein of SARS-CoV-2 mediates the viral cell-to-cell transmission, with an efficiency higher than that of SARS-CoV. We also find that cell–cell fusion contributes to cell-to-cell transmission, yet ACE2 is not absolutely required. While the authentic variants of concern (VOCs) B.1.1.7 (alpha) and B.1.351 (beta) differ in cell-free infectivity from wild type and from each other, these VOCs have similar cell-to-cell transmission capability and exhibit differential sensitivity to neutralization by vaccinee sera. Results from our study will contribute to a better understanding of SARS-CoV-2 spread and pathogenesis."
This team was trying to find out the reasons behind why the original SARS (2003) led to much higher fatality rates and lasted only eight months. (There was another reason as well which I did mention several times why SARS disappeared)
The original 2003 SARS is more efficient than SARS-CoV-2 at what is called cell-free transmission, when freely floating viral particles infect target cells by binding to a receptor on their surface – but also remain vulnerable to antibodies produced by previous infection and vaccines. SARS-CoV-2, on the other hand, is more efficient at cell-to-cell transmission – which makes it harder to neutralize with antibodies.
This team found unexpectedly, that cells with no or low levels of ACE2 on their surfaces can be penetrated by the virus, enabling robust cell-to-cell transmission.
To summarize
"There is no perfect correlation between SARS-CoV-2 infection and the level of ACE2. ACE2 may be needed for initial infection, but once infection is established, the virus may not need ACE2 anymore because it can spread from cell to cell."
Shan-Lu Liu, virology professor, The Ohio State University.
PS: Pls read
https://elakiri.com/threads/omicron-monoclonal-antibodies-are-ineffective.2024092/
"Significance
It is currently unknown if SARS-CoV-2 can spread through cell–cell contacts, and if so, the underlying mechanisms and implications. In this work, we show, by using lentiviral pseudotyped virus, that the spike protein of SARS-CoV-2 mediates the viral cell-to-cell transmission, with an efficiency higher than that of SARS-CoV. We also find that cell–cell fusion contributes to cell-to-cell transmission, yet ACE2 is not absolutely required. While the authentic variants of concern (VOCs) B.1.1.7 (alpha) and B.1.351 (beta) differ in cell-free infectivity from wild type and from each other, these VOCs have similar cell-to-cell transmission capability and exhibit differential sensitivity to neutralization by vaccinee sera. Results from our study will contribute to a better understanding of SARS-CoV-2 spread and pathogenesis."
This team was trying to find out the reasons behind why the original SARS (2003) led to much higher fatality rates and lasted only eight months. (There was another reason as well which I did mention several times why SARS disappeared)
The original 2003 SARS is more efficient than SARS-CoV-2 at what is called cell-free transmission, when freely floating viral particles infect target cells by binding to a receptor on their surface – but also remain vulnerable to antibodies produced by previous infection and vaccines. SARS-CoV-2, on the other hand, is more efficient at cell-to-cell transmission – which makes it harder to neutralize with antibodies.
This team found unexpectedly, that cells with no or low levels of ACE2 on their surfaces can be penetrated by the virus, enabling robust cell-to-cell transmission.
To summarize
"There is no perfect correlation between SARS-CoV-2 infection and the level of ACE2. ACE2 may be needed for initial infection, but once infection is established, the virus may not need ACE2 anymore because it can spread from cell to cell."
Shan-Lu Liu, virology professor, The Ohio State University.
PS: Pls read
https://elakiri.com/threads/omicron-monoclonal-antibodies-are-ineffective.2024092/
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