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 RNA polymerase in the RTC (replication transcription complex), thereby preventing infection. This makes RNA 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 الكورونا في العام.
كوفيد-19 وباء 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 فيروس or developed antibodies against it. This resistance has been attributed to the ذاكرة T cells-possibly those that are produced after exposure of the human system to such الفيروسات.
في دراسة حديثة نُشرت في Nature بواسطة Swalding et al. ، عينات دم مأخوذة من 60 عاملاً في مجال الرعاية الصحية ، كانوا معرضين بدرجة عالية للإصابة كوفيد-19 due to their exposure, were examined and found out to be negative for the فيروس 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 بوليميراز الحمض النووي الريبي in the RTC (replication transcription complex), rather than any other structural protein of the فيروس. These memory T cells could have been generated in the health care workers by being exposed to other respiratory or related corona الفيروسات, 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 الفيروسات, including SARS-CoV-2. This may also be responsible for viral clearance in individuals, pre-exposed to other respiratory الفيروسات, and then infected with SARS-CoV-2.
The fact that the memory T cells are directed against the RNA polymerase (being the most conserved among the human الكورونا that cause common cold and SARS-CoV-2), makes this enzyme an important target to develop a pan-التاجى 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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المصدر
Swadling ، L. ، Diniz ، MO ، Schmidt ، NM et al. تتوسع الخلايا التائية الخاصة بالبوليميراز الموجودة مسبقًا في SARS-CoV-2 المجهض. طبيعة (2021). https://doi.org/10.1038/s41586-021-04186-8
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