Resistance to COVID-19 infection has been observed in health care workers and has been attributed to the presence of memory T cells that target the РНК polymerase in the RTC (replication transcription complex), thereby preventing infection. This makes РНК polymerase an important target for making a pan-coronavirus vaccine that will be effective against SARS-CoV-2 and its other variants of concern (VoC’s), but also against the family of Коронавіруси в цілому.
COVID-19 пандемія is now almost 2 years old and has caused havoc among the world by disrupting world economy and halting the normal way of living. Millions have died and many more have been infected with the disease leading to high levels of morbidity. However, there have been instances where people have cleared the infection from the system so quickly that they didn’t test positive for the вірус or developed antibodies against it. This resistance has been attributed to the пам'ять T cells-possibly those that are produced after exposure of the human system to such віруси.
У нещодавньому дослідженні, опублікованому в Nature Swalding et al., зразки крові 60 медичних працівників, які мали високий ризик розвитку COVID-19 due to their exposure, were examined and found out to be negative for the вірус and for the antibodies against the virus1. It is hypothesised that pre-existing memory T-cells, with cross-protective potential against SARS-CoV-2, expand in vivo to provide rapid viral clearance, thus aborting infection. These T cells are directed against the РНК-полімераза in the RTC (replication transcription complex), rather than any other structural protein of the вірус. These memory T cells could have been generated in the health care workers by being exposed to other respiratory or related corona віруси, albeit there is no direct evidence of the same. It is also possible that there were other environmental triggers that led to the generation of these T cells. In addition, these sero-negative individuals also showed an increase in IFI27, a protein indicative of abortive SARS-CoV-2 infection. IFI27 is an interferon alpha inducible protein that is overexpressed upon exposure to a variety of respiratory віруси, including SARS-CoV-2. This may also be responsible for viral clearance in individuals, pre-exposed to other respiratory віруси, and then infected with SARS-CoV-2.
The fact that the memory T cells are directed against the РНК polymerase (being the most conserved among the human коронавіруси that cause common cold and SARS-CoV-2), makes this enzyme an important target to develop a pan-коронавірус vaccine that would not only be directed against SARS-CoV-2 and its other variants of concern (VoC’s) that have evolved as a result of mutations in the spike protein leading to more severe disease, but also against the family of Coronaviruses in general.
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джерело:
Swadling, L., Diniz, MO, Schmidt, NM et al. Існуючі Т-клітини, специфічні для полімерази, розширюються при абортивному серонегативному SARS-CoV-2. Природа (2021). https://doi.org/10.1038/s41586-021-04186-8
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