Memory cells in the nose slow the influenza virus as soon as it enters the body. They reduce viral levels and may help protect against more severe\u00a0illness. The study from the University of Gothenburg may help guide the development of better influenza vaccines.\u202f<\/p>\n
Today’s influenza vaccines are given as injections in the arm and\u202fmainly stimulate\u202fimmune responses in the blood. At the same time, researchers are working to develop influenza vaccines that can be administered through the nose-an effort this study helps inform. The goal is to strengthen the body’s defenses where the virus first\u202fencounters\u202fthe immune system.\u202f<\/p>\n
Memory cells\u202fremain\u202fin the nose\u202f<\/p>\n
The researchers\u202fidentified\u202fa group of memory cells, known as CD4 memory T cells, that remain in nasal tissue after an influenza infection. When the body\u202fencounters\u202fthe virus again, these cells can rapidly reactivate and help other parts of the immune system fight the infection. The study shows that these cells can reduce viral replication in the nose and thereby contribute to better protection against illness.\u202f<\/p>\n
We show that CD4 memory T cells can remain in nasal tissue after an influenza infection and rapidly reactivate when the virus returns. This means the immune system can respond directly\u202fat\u202fthe site where the virus first enters the body.”<\/p>\n
Nimitha R. Mathew, researcher at the\u202fSahlgrenska\u202fAcademy, University of Gothenburg, and one of the study’s lead authors<\/p>\n
In studies in mice, the researchers showed that these immune cells help limit viral levels\u202fand reduce tissue damage\u202fin the nose during a\u202fsubsequent\u202finfection.\u202f\u202f<\/p>\n
Similar cells found in humans\u202f<\/p>\n
The researchers also analyzed cells from the nasal mucosa of healthy adults. There, they found the same type of\u202finfluenza-specific\u202fmemory cells, suggesting that a similar local immune defense may also exist in humans. The study is published in the\u202fJournal of Experimental Medicine.\u202f<\/p>\n
“Many people\u202flikely already\u202fhave these kinds of memory cells in their noses after\u202fprevious\u202finfections, but they are not always enough to stop the virus completely. The important thing about our findings is that we now know which immune cells can limit the virus where infection begins. That knowledge can be used when developing future nasal vaccines,” says Davide Angeletti, professor at the\u202fSahlgrenska\u202fAcademy, University of Gothenburg,\u202fand also\u202fone of the study’s lead authors.<\/p>\n
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