Kihong Lim, Ph.D.

When a person is infected with influenza, various immune cells infiltrate into the infected airway to eliminate disease-causing germs. Understanding how the body responds during the infection is a key to improving control of influenza infection. We recently discovered a novel mechanism by which white blood cells called neutrophils guide the migration of immune cells called CD8 T cells to their destination. CD8 T cells destroy infected cells lining the airways to stop the production and spread of the influenza virus. Neutrophils also guide another type of white blood cell called monocytes. Because the roles of monocytes in influenza infection are not clearly understood, we aim to analyze the integrated functions of neutrophils and monocytes and how they work to defeat the influenza virus.

Update: With a mouse influenza infection model, we identified a novel mechanism that neutrophils use to promote tissue healing and resolution of inflammation. We discovered that neutrophils in the influenza-infected airway released a key protein, epidermal growth factor (EGF). Generally, EGF promotes cell survival and proliferation. Our data showed that EGF secreted from neutrophils directly enhanced the proliferation of cells lining the airways called epithelial cells, and support the survival of alveolar macrophages, cells that are responsible for removing particles such as dust or microorganisms from the respiratory surfaces. Understanding the molecular basis of neutrophil response in the infected airways and its functions in tissue resolution may lead to effective therapeutic approaches to treat influenza infection.