The impact of bacterial superinfection during influenza infection of allergic hosts

Autor: Amali Samarasinghe, Kim LeMessurier, Amy Iverson, Jason Rosch, Jonathan McCullers
Rok vydání: 2016
Předmět:
Zdroj: The Journal of Immunology. 196:200.3-200.3
ISSN: 1550-6606
0022-1767
DOI: 10.4049/jimmunol.196.supp.200.3
Popis: Allergic asthma can be complicated by respiratory pathogens. However, asthmatics suffered less severe morbidity and mortality compared to non-asthmatics during the 2009 influenza A virus (IAV) pandemic. Using a novel mouse model, we determined that IAV infection during allergic airways inflammation protects the host from influenza. Pathogen-pathogen interactions between IAV and Streptococcus pneumoniae (Spn) can lead to fatal outcomes in a healthy host. We hypothesized that allergic hosts will have less morbidity and mortality associated with Spn superinfection after influenza. Infectious IAV was undetectable in the lungs at 72 h after Spn. Similar to animals infected with Spn alone, asthma+Spn mice cleared the bacteria completely by 72 h. Bacterial burden increased in the bronchoalveolar lavage fluid (BALF), lungs, and blood of mice in the IAV+Spn co-infection group. However, bacterial load in animals subjected to the fungal asthma model prior to viral and bacterial infections were significantly reduced in the BALF and absent in the lungs and blood. More leukocytes were found in the BALF of mice infected with IAV. The number of macrophages was similar between all groups, while those in the asthma+IAV, asthma+Spn, asthma+IAV+Spn groups had prominent amounts of eosinophils and CD4+ T cells (30% each) in the airways which was significantly higher than the asthma-only, IAV-only, Spn-only, and IAV+Spn groups. Neutrophils were most abundant in the IAV+Spn controls while the greatest number of CD8+ T cells was present in the IAV-only controls. The lung microbiome was significantly different in asthma+IAV+Spn. Remarkably, the asthma+IAV+Spn group did not have severe morbidity or mortality typically associated with IAV+Spn coinfection.
Databáze: OpenAIRE
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