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 moléculas de ARN polymerase in the RTC (replication transcription complex), thereby preventing infection. This makes moléculas de ARN 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 Coronaviruses in general.
COVID-19 pandemia 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 virus or developed antibodies against it. This resistance has been attributed to the memory T cells-possibly those that are produced after exposure of the human system to such virus.
En un estudio reciente publicado en Nature por Swalding et al., muestras de sangre de 60 trabajadores de la salud, que tenían un alto riesgo de desarrollar COVID-19 due to their exposure, were examined and found out to be negative for the virus 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 ARN polimerasa en el RTC (complejo de transcripción de replicación), en lugar de cualquier otra proteína estructural del virus. Estas células T de memoria podrían haberse generado en los trabajadores de la salud al estar expuestos a otros coronavirus respiratorios o relacionados, aunque no hay evidencia directa de lo mismo. También es posible que hubiera otros desencadenantes ambientales que condujeran a la generación de estas células T. Además, estos individuos seronegativos también mostraron un aumento en IFI27, una proteína indicativa de infección abortiva por SARS-CoV-2. IFI27 es una proteína inducible por interferón alfa que se sobreexpresa tras la exposición a una variedad de virus respiratorios, incluido el SARS-CoV-2. Esto también puede ser responsable de la eliminación viral en individuos, expuestos previamente a otros virus respiratorios y luego infectados con SARS-CoV-2.
The fact that the memory T cells are directed against the moléculas de ARN polymerase (being the most conserved among the human coronavirus that cause common cold and SARS-CoV-2), makes this enzyme an important target to develop a pan-coronavirus 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.
***
Fuente:
Swadling, L., Diniz, MO, Schmidt, NM y col. Las células T preexistentes específicas de la polimerasa se expanden en el SRAS-CoV-2 seronegativo abortivo. Naturaleza (2021). https://doi.org/10.1038/s41586-021-04186-8
***
