{"id":4969,"date":"2020-02-24T19:24:40","date_gmt":"2020-02-24T10:24:40","guid":{"rendered":"http:\/\/163.180.4.222\/lab\/?p=4969"},"modified":"2020-02-24T19:42:03","modified_gmt":"2020-02-24T10:42:03","slug":"toward-a-universal-flu-vaccine","status":"publish","type":"post","link":"https:\/\/biochemistry.khu.ac.kr\/lab\/?p=4969","title":{"rendered":"Toward a universal flu vaccine"},"content":{"rendered":"

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Influenza virus infections pose a major public health threat, accounting for 3.5 million severe infections and more than 400,000 deaths globally each year (1<\/em><\/a>). Most seasonal vaccines consist of inactivated influenza virus components, which induce antibody responses against immunodominant epitopes in the viral hemagglutinin (HA) and neuraminidase (NA) proteins. The genes that encode HA and NA undergo continuous changes (antigenic drift), which necessitates annual reformulation and revaccination, leading to reduced vaccine coverage. Vaccine effectiveness thus varies depending on the accuracy of preseasonal predictions, and inactivated seasonal influenza vaccines generally provide insufficient protection against pandemic viruses (2<\/em><\/a>). On page 869 of this issue, Wang\u00a0et al.<\/em>\u00a0(3<\/em><\/a>) explore an unconventional strategy to overcome these shortcomings by complementing inactivated influenza virus vaccines with an adjuvant that triggers mucosal immune responses to elicit rapid protection against a variety of influenza virus strains in mice and ferrets.<\/p>\n

Current strategies for the development of such universal flu vaccines mainly focus on the generation of broadly protective antibodies directed against conserved but immunosubdominant viral surface epitopes that are accessible to antibody binding, such as the stalk region of HA and, recently, the active site of NA (4<\/em><\/a>,\u00a05<\/em><\/a>). In contrast to antibody responses (which are produced by B cells), virus-specific CD8+<\/sup>\u00a0T cells generated in response to natural influenza virus infection may provide broad protection against infections with numerous virus subtypes (heterosubtypic protection) (6<\/em><\/a>).<\/p>\n

2′,3′-cyclic guanosine monophosphate\u2013adenosine monophosphate (cGAMP) is a second messenger produced in response to viral infections and a potent activator of the innate immune sensor stimulator of interferon genes (STING) (7<\/em><\/a>). To mimic natural influenza infection and to elicit CD8+<\/sup>\u00a0T cell\u2013mediated immunity, Wang\u00a0et al.<\/em>\u00a0used cGAMP as an adjuvant to an inactivated influenza virus vaccine. Pulmonary surfactant (PS) is a phospholipoprotein complex produced by alveolar epithelial cells (AECs) to reduce surface tension and prevent alveolar collapse. Because PS is recognized by lung-resident alveolar macrophages, the authors used lipid components of PS to encapsulate cGAMP. They found that intranasally administered PS-GAMP nanoparticles were readily taken up by alveolar macrophages in mice. cGAMP was transferred from alveolar macrophages to AECs, where STING was subsequently activated.<\/p>\n

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