Viral Infection Left Mice With Scarred Spleens, Vaccines Prevented It
A mouse study found an acute viral infection left lasting spleen scarring and weak T-cell responses, and prior vaccination prevented the damage.
Mice that recovered from an acute viral infection were left with scarred spleens and weaker immune responses long after the virus was gone, researchers at Pompeu Fabra University in Barcelona report. Mice vaccinated before the infection showed none of that damage.
The study was done in mice only, and the authors say it does not show the same thing happens in people. It does suggest that vaccines may protect the immune system itself, beyond preventing the illness.
What happened inside the recovered mice
The team, from the university’s Infection Biology Laboratory, infected mice with an acute virus and followed them after they cleared it. Getting rid of the virus did not bring the immune system back to normal.
The lasting problem was in the spleen, an organ that helps organize the body’s immune defenses. While the immune system fought the virus, the spleen developed fibrosis, a buildup of scar-like tissue. Immune cells inside the organ also ended up out of their usual positions.
Those changes got in the way of the contact between immune cells that is needed to switch on T cells. T cells are part of adaptive immunity: they learn to recognize infected cells and destroy them. With that process disrupted, the recovered mice responded poorly to new immune challenges.
“The infection can be controlled, but that does not necessarily mean that the host has fully recovered,” said Paula Cebollada Rica, the study’s first author. She said the mice were left immunocompromised after the virus could no longer be detected.
Vaccinated mice kept normal spleens
The researchers then tested whether vaccination before infection made a difference. It did. Vaccinated mice kept the normal structure of their spleens, and their T cells worked about as well as those of mice that had never been infected.
According to Cebollada Rica, vaccination both prevented the disease from the infection and kept the immune system able to handle new challenges afterward.
Why it matters
Most people treat a cold or a stomach bug as a short event that ends when symptoms fade. Study leader Andreas Meyerhans, an ICREA research professor at UPF, said that view may underestimate hidden effects that last after the infection is over.
If similar damage happens in people, vaccines would have a benefit that is easy to miss: guarding the immune system against harm from the fight itself. That remains an open question. The results come from a mouse model, and the authors say they do not establish that the effect occurs in humans.
The researchers also linked the work to public health debates. Meyerhans said people should know about the broader protection vaccination can provide, and he described vaccines as delivering strong health benefits at a relatively low cost to society.
Where the research was published
The study appeared in Cell Death & Disease, according to Universitat Pompeu Fabra, under the title “Temporal lymphatic tissue destruction and impairment of de novo T cell responses after an acute virus infection.” The DOI is 10.1038/s41419-026-09253-4.
The next step the findings point to is research on how viral infections affect long-term immune health in people, and whether vaccination protects it in the same way.
Source: ScienceDaily
