Researchers from the Université Paris Cité and CNRS in France have conducted a study to better understand the factors that contribute to variability in immune responses to the SARS-CoV-2 virus. The study, which involved analyzing the immune responses of 222 healthy blood donors, has shed light on why susceptibility to the virus is not uniform among individuals.
Using single-cell RNA sequencing, the researchers examined the immune responses of individuals from different geographical regions and ancestries. The findings revealed that SARS-CoV-2 induces weaker but more varied interferon-stimulated gene activity compared to the influenza A virus. This variability in immune response can be attributed to factors such as population genetics, demographics, and environment.
One notable finding from the study is that older individuals generally exhibit weaker immune responses. This could help explain why they are more susceptible to severe cases of COVID-19. Additionally, individuals with underlying health conditions also show altered immune responses, potentially increasing their susceptibility and leading to poorer outcomes.
The study also uncovered disparities among different populations in terms of their immune responses. The proportions of memory cells in lymphoid lineages differed among individuals of African, European, and East Asian descent. This contributes to the population disparities in immune responses to the virus.
Interestingly, past viral encounters play a role in immune responses as well. For example, individuals who had previously been infected with cytomegalovirus (CMV) exhibited differences in their immune responses compared to those who hadn’t been infected. These differences were observed among different populations.
The researchers also found that genetics have a range of effects on different cell types and immune responses, with common genetic variants contributing to variations in the immune response. In particular, Neanderthal genes were found to have influenced present-day immune responses to SARS-CoV-2. Certain gene variants affected immunity phenotypes and decreased susceptibility to COVID-19 in specific populations.
Overall, the study highlights the complexity of immune responses and the interplay between environmental, genetic, and evolutionary factors. Understanding these factors is crucial in comprehending how the immune system responds to novel threats like the SARS-CoV-2 virus and how it develops and maintains responses over evolutionary time scales.
“Infuriatingly humble tv expert. Friendly student. Travel fanatic. Bacon fan. Unable to type with boxing gloves on.”