Most flu vaccines are built to trigger antibodies. New research points to a different, longer-lasting form of protection — and an unexpected immune cell in the lungs that could make flu shots work better.
Scientists at the University of Rochester, led by Dr. Minsoo Kim, found that certain monocyte-derived cells persist in the lungs for months after a flu infection, producing a protein called galectin-1. That protein sustains tissue-resident memory T cells (TRM cells) right at the site of viral entry — keeping the respiratory tract’s defenses primed. The findings were published in Nature Immunology.
Turning it into a vaccine boost
When the researchers added galectin-1 to an experimental nasal flu vaccine in mice, the lung immune response strengthened significantly. That suggests galectin-1 could serve as an adjuvant in nasal vaccines — boosting mucosal immunity to stop infection at the point of entry, not just prevent severe disease.
Why it matters
“This challenges the traditional view that immune memory is driven only by T and B cells, and shows that innate immune cells also play a lasting role,” Kim said. Vaccines that establish strong, local defenses in the airways are a long-sought goal — potentially reducing transmission, not just illness. This is early, mouse-stage research, but it offers a concrete new lever for designing more protective respiratory vaccines.