Sequencing more than 170,000 single cells from animal models have provided exceptionally detailed insight into the early immune response to SARS-CoV-2 in the lungs. The findings will help inform future treatment options for the current pandemic and future coronaviruses.
Researchers at Texas Biomedical Research Institute and Southwest National Primate Research Center (SNPRC), in collaboration with Washington University in St. Louis, have clarified what immune cells are present in the lungs in the first days of SARS-CoV-2 infection, and what some of those cells are doing to fight off the virus. The findings, reported in Nature Communications this week, will help guide the development of future treatments for COVID-19.
«This is the most detailed analysis of early SARS-CoV-2 infection to date thanks to the latest single-cell sequencing technologies, and animal models developed at Texas Biomed and SNPRC,» says Deepak Kaushal, Ph.D., SNPRC Director and senior paper author.
The analysis has shed light on a key mystery throughout the COVID-19 pandemic: the role of a class of signaling proteins called Type I Interferons (IFN). During viral infections, interferon molecules act like sentries or alarm bells blaring «intruder alert!» to other cells, so they can boost their defense systems. However, some reports have shown a lower Type I Interferon response to SARS-CoV-2, allowing the virus to spread more readily. At the same time, runaway interferon «cytokine storms» have been a hallmark of severe COVID-19.
Scientists have been trying to figure out if interferon fights SARS-CoV-2 or is somehow dysregulated, especially early on in infection. Clarifying this is important for developing treatments that aim to limit harmful inflammation linked to excessive interferon activity, without blocking its protective mechanisms.
This new research shows interferon plays a key role in clearing the virus, by alerting other immune cells, called macrophages, to search and destroy the virus. Macrophages are akin to Pac-Man, gobbling up cells infected with the virus.
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Materials provided by Texas Biomedical Research Institute. Note: Content may be edited for style and length.