A recent study conducted by researchers at Erlangen University Hospital in Germany found that our gut’s immune response to COVID-19 may not provide long-term systemic immunity compared to an immune response triggered elsewhere in the body.
The results of the study were published in the journal Limits in immunology.
“Although the gut is considered an important entry portal for the virus, the immune response in the blood of patients with COVID-19 is dominated by lymphocytes – cells that protect the body from infection – triggered by other areas of the body,” said Sebastian Zundler, author of the study. “Further work is needed, but these findings may have implications for oral COVID-19 vaccines.”
For the research, the researchers used a technique that detects and measures various immune cells found in the blood, called flow cytometry. They used it to analyze blood samples from people who were currently infected with COVID-19, those who had recovered from the disease and those who did not have the virus.
“In the lymphoid tissue of the gut, there is a special mechanism that drives the production of a fingerprint marker called‘ a4b7 integrin ’,” said Tanja Müller, lead author of the study. “This marker causes T cells to move toward the gut to fight infection. With this marker, we can determine if there are circulating lymphocytes in the blood that are triggered by the gut’s immune response.”
The researchers found relatively few immune cells that had a4b7 markers in the blood of those patients with COVID-19 infection. The authors hypothesized that this could be due to dilution caused by cells created at other sites of infection.
Our study adds to our understanding of the human immune response to SARS-CoV-2 infection, but we cannot yet definitively answer the question of the fate of immune cells implanted in the gut – whether they are “diluted” or “attracted” elsewhere. and lung samples will help us answer this important question, ”Zundler said.