On July 7-11, 2024, the SMBE 2024 conference was held in Puerto Vallarta, Mexico, under the auspices of the Society for Molecular Biology and Evolution. 

At the conference, PhD student Ekaterina Ryumina from the Skoltech Center for Molecular and Cellular Biology presented the work titled “HLA class I escape drives the evolution of SARS­CoV­2 in human population” co-authored with Evgenia Alekseeva, Galina Klink, and Georgy Bazykin, where Ekaterina reported that SARSCoV2 evolution is shaped by human adaptive immunity, with mutations that allow escape from the B cell response conferring selective advantage and spreading in the population. 

Meanwhile, the role of the escape from T-cellular cytotoxic response remains controversial. The authors study the origin and spread of SARS CoV2 variants that allow escape from presentation by the HLA class I alleles that are common in human populations. The research found that 35% of mutations that are characteristic of the variants of concern, and 34% of mutations that have reached high (>5%) frequencies in viral populations, facilitate escape from T cellular alleles. Mutations associated with escape from common HLA alleles reach higher frequencies than those that allow escape from less common HLA alleles. Moreover, viral escape mutations reach higher frequencies in those countries where the causal HLA alleles are more frequent, indicating that viral escape is driven by the local genetic composition of the human host population. Together, these data indicate that CTL escape is a major driver of SARS CoV2 evolution and an epidemiological concern, and reveal a novel facet of selection on this virus. The study was supported by the grant from the Russian Science Foundation No. 21-74-20160.