Role of BPIFA1 in the pathogenesis and immune response against Influenza A virus in mice

The epithelial layer of the respiratory system has a critical role in the defense against microbes and secretes a number of proteins that function in host defense. BPIFA1 is secreted by the epithelium of the respiratory tract and we have shown previously that it inhibits binding and entry of Influenza A Virus (IAV) into respiratory epithelium (Akram et al. 2018), Mucosal Immunol (11, 71). However, its precise biological functions remain unclear. The aim of this study was to assess the influence of BPIFA1 in antibody production during IAV infection. BPIFA1 KO and wild type C57BL/6J mice were infected with IAV using different virus doses and blood, broncho-alveolar lavage and nasal washes were collected at several time points for analysis of IAV-specific antibodies. The results showed that BPIFA1 has role in the efficient generation of virus-specific IgA in the respiratory tract. Thus, BPIFA1 has an important role not only in innate defense but also in the adaptive immune response against IAV.