A research team at the University of Basel discovered residing immune cells in the lungs that persist long after a flu bout. Experiments with mice showed that these helper cells improved the immune response to infection again with a different strain of influenza virus. This discovery could lead to an approach to developing long-term vaccines against rapidly mutating viruses.
At the start of the coronavirus epidemic, some are already starting to raise the question of how long immunity lasts after weathering from SARS-CoV-2. The same question has now arisen regarding vaccination against COVID-19. Immunological memory plays a major role – a complex interaction between immune cells, antibodies and signaling substances that allow the body to fight known pathogens very efficiently.
Researchers led by Professor Caroline King from the Department of Biomedicine at the University of Basel have identified a variety of immune cells in the lungs that are essential to the defense against reinfection with influenza viruses. The same could apply to re-infection with other pathogens that cause respiratory illnesses.
In experiments with mice, researchers identified a group of memory T cells in lung tissue that remain long after a flu bout. The team reports on these “resident helper T cells” in the peer-reviewed journal Immunology.
Reservoir inside the tissue
“Relatively little is known about the memory T cells that remain in the tissues,” said Nvidia Swarnaleja, co-first author of the study. Previous studies have focused on memory cells in blood and lymph tissue. “But it stands to reason that the body maintains a reservoir of these cells in infected tissues, where they can invade the same or similar pathogens again.”
In their study, the researchers described two types of T helper cells in the lungs. One type releases signaling substances in case of reinfection to provide other immune cells with more lethal “weapons” in combating pathogens. The other type, formerly characterized by lymphoid tissue and thought to be absent in lung tissue, aids antibody-producing immune cells (B cells) and locates closely with them in the lung.
The researchers were able to show that the presence of these cells in direct proximity to the antibody-producing B cells resulted in a more efficient immune response against a different influenza virus.
A starting point for long-lasting vaccine protection
“These helper T cells could be an interesting starting point for long-term influenza vaccination,” says David Schreiner, another first co-author of the study, adding that it may be possible, for example, to supplement vaccines with factors that promote the formation of these helper T cells that migrate To the tissues. To this end, more research and development is needed.
Professor Caroline King
[email protected]http: // dx.