5 March — T cells might provide rescue from rampant coronavirus variants

Emerging coronavirus variants do not seem to elude important immune-system players called T cells, laboratory studies suggest.

Some recently discovered SARS-CoV-2 variants can partially evade antibodies generated in response to vaccination and previous infection,raising fears that vaccines will be less effective against the variants than against the original strain of the virus. Alessandro Sette and Alba Grifoni at the La Jolla Institute for Immunology in California and their colleagues looked at whether these variants’ mutations might also help them to evade T cells — a component of the immune system that is particularly important for reducing the severity of infectious diseases (A. Tarke et al. Preprint at bioRxiv https://doi.org/gh6tkp; 2021).

The team collected T cells from volunteers who had either recovered from infection with the ancestral SARS-CoV-2 strain or had received an mRNA coronavirus vaccine. The researchers then tested the cells’ ability to recognize protein snippets from four emerging variants, including the B.1.351 variant first identified in South Africa.

Most of the volunteers’ T cells recognized all four variants, thanks to viral protein snippets that were unaffected by the variants’ mutations. The results suggest that T cells could target these variants.