Pompeu Fabra University: mice recovered from LCMV infection kept spleen damage and weak T cell responses
In mice, acute LCMV infection left lasting destruction of splenic lymphatic tissue and impaired T cell priming; prior vaccination prevented both, the authors report.
Researchers at Pompeu Fabra University in Barcelona, led by Andreas Meyerhans, studied mice after acute infection with lymphocytic choriomeningitis virus (LCMV). In a paper in Cell Death and Disease, they report that animals that had recovered from the infection stayed immunocompromised for a prolonged period, mainly in de novo T cell responses nature.com
Cell Death and Diseasenature.comOpen source ↗. The first author is Paula Cebollada Rica. The work was done in mice, and it does not establish that the same effects occur in humans.
Destruction of splenic lymphatic tissue
The team combined mouse infections, different vaccine regimens and immune monitoring. They examined lymphatic tissues with fluorescence microscopy and 3D image reconstruction. The weakened T cell response was linked to massive destruction of splenic lymphatic tissue. This affected the compartmentalization of the organ and the cell–cell contacts that are necessary for efficient T cell priming.
The university's release adds that the spleen developed fibrosis, a buildup of scar-like tissue, and that the arrangement of immune cells within the organ was disrupted. As a result, the recovered mice were less able to mount effective responses to new challenges, even though the original infection was under control.
According to Cebollada Rica, the infection can be controlled without the host having fully recovered. The immune-related consequences can persist beyond the period in which the virus is detectable.
Effect of vaccination
The authors also tested vaccination. LCMV vaccination prevented the destruction of lymphatic tissue and the compromised immune state nature.com
Cell Death and Diseasenature.comOpen source ↗. According to the release, the spleens of vaccinated mice kept their normal structure, and their T cells worked at levels comparable to those of mice that had never been infected.
The authors conclude that vaccination is important for preventing both the pathology of acute virus infection and potential post-acute infection sequelae (PAIS). PAIS is the term for diverse immunological alterations and clinical syndromes that follow an acute viral infection and remain poorly understood.
The results challenge the common assumption that a host returns to its pre-infection homeostatic health state as soon as an acute virus infection is controlled. The study points to an interplay between virus infection, immune response and tissue integrity.
