Interferon-Induced Protein Protects Against Recurring Influenza Infections

Following infection of the body by the influenza virus, protective immune cells called resident memory T-cells (TRM cells) are stationed in lung and respiratory mucosal tissues where they express a specific membrane protein that helps prevent reinfection.

Investigators at the University of Melbourne (Australia) reported in the January 27, 2013, online edition of the journal Nature Immunology that infection with influenza virus resulted in the deposition of anti-influenza CD8+ TRM cells in the lung mucosal tissue. These TRM cells selectively maintained expression of the interferon-induced transmembrane protein IFITM3 (interferon-induced transmembrane protein 3).

IFITM3 is an interferon-induced membrane protein that helps confer immunity to influenza A H1N1 virus, West Nile virus, and Dengue virus. It has been reported to play a critical role in the immune system's defense against swine flu, where heightened levels of IFITM3 kept viral levels low, and the removal of IFITM3 allowed the virus to multiply unchecked. This observation was further advanced by a recent study that showed that a single nucleotide polymorphism (SNP) in the human IFITM3 gene that increased influenza susceptibility was overrepresented in people hospitalized with pandemic H1N1.

“If we learn how to increase the number and longevity of T-cells expressing IFITM3, this could lead to improved vaccines that promote the generation of more resistant T-cells able to provide the greatest protection, for longer,” said senior author Dr. JoseVilladangos, professor of microbiology and immunology at the University of Melbourne.

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