COVID variants can escape immune system ‘killers’

Omicron subvariants of SARS-CoV-2 evade T cell destruction.

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Omicron subvariants of

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, has shown an extraordinary ability to overcome antibodies developed by vaccinations or previous versions of the virus, resulting in numerous breakthrough infections. 

However, to cause illness in humans, these viral variations must also dodge “killer” T cells, which are immune cells released when the immune system detects foreign infections.

A new Yale study published on April 10 in the Proceedings of the National Academy of Sciences gives new light on how Omicron subvariants of SARS-CoV-2, the virus that causes COVID-19, resist T cell destruction. 

According to Moriyama, who works in Akiko Iwasaki’s lab as a Sterling Professor of Immunobiology, The activity of these MHC molecules was significantly lower in cells exposed to five Omicron subvariants of SARS-CoV-2 as well as earlier types of the virus.

However, compared to earlier versions of the COVID-19 virus, the Omicron variants were particularly effective at reducing MHC activity. Meanwhile, cells inoculated with the flu virus were shown to have significantly higher MHC activation.

Researchers from yale university believe that decreased activity in these MHC molecules may make T cells less likely to find COVID viral targets.

Moriyama said, “The findings will help guide researchers as they investigate possible ways to overcome MHC suppression by viral infections and may help in the development of vaccines that mobilize T cells as well as antibody response against viruses.” 

Journal Reference:

Moriyama, M., Lucas, etal. Enhanced inhibition of MHC-I expression by SARS-CoV-2 Omicron subvariants. Proceedings of the National Academy of Sciences. DOI:10.1073/pnas.2221652120

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