July 25, 2024

Role of Innate Immunity in the Persistence of SARS-CoV-2 in the Lungs

New research conducted by the Institut Pasteur and the Alternative Energies and Atomic Energy Commission (CEA) has revealed the persistence of the SARS-CoV-2 virus in the lungs of certain individuals for up to 18 months after infection. The study, published in Nature Immunology, suggests that the prolonged presence of the virus in the lungs may be linked to a failure of the innate immune system, which is the body’s first line of defense against pathogens.

While it is known that some viruses can remain latent in the body after causing an infection, such as HIV, the possibility of SARS-CoV-2 persisting in a similar manner has been a topic of speculation. The recent study aimed to investigate this hypothesis by analyzing lung cells in an animal model.

The results of the study indicate that the virus can be detected in the lungs of certain individuals even when it is no longer detectable in the upper respiratory tract or blood, suggesting the presence of viral reservoirs. These reservoirs are believed to contribute to the long-term persistence of the virus in the body.

One surprising finding of the study was that the amount of persistent virus in the lungs was lower for the omicron strain compared to the original SARS-CoV-2 strain. Additionally, the researchers discovered that the virus was present in immune cells called alveolar macrophages, which were still capable of replicating.

To understand the role of innate immunity in controlling these viral reservoirs, the scientists focused on natural killer (NK) cells, which are a part of the innate immune response. It was observed that in some animals, macrophages infected with SARS-CoV-2 became resistant to destruction by NK cells. However, in other cases, NK cells adapted to the infection and were able to destroy the infected cells.

This indicates that adaptive NK cells play a crucial role in controlling viral infections, including SARS-CoV-2. The study also highlights the importance of innate immunity in the regulation of persistent viral infections. The researchers plan to further investigate these mechanisms and their potential relationship with long COVID cases by studying individuals infected with SARS-CoV-2 at the beginning of the pandemic.

Overall, this study contributes to our understanding of the nature of viral reservoirs and the factors that influence the persistence of SARS-CoV-2 in the lungs. Further research in this area could help develop strategies to prevent and treat long-term complications associated with COVID-19.

1. Source: Coherent Market Insights, Public sources, Desk research
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