Abstract
Asthma is a global problem that affects millions of individuals. An increased risk of respiratory viral and bacterial infections is one of the complications of asthma. We recently reported that mice with ovalbumin-induced allergic airway disease (AAD) are protected against influenza-Streptococcus pneumoniae co-infection. Here, we describe in detail a protocol on how to induce AAD and influenza-S. pneumoniae co-infection in mice and to evaluate the specific roles of asthma on immunity to viral and bacterial pathogens in the hope of translating findings to benefit asthmatic individuals.
Keywords: Asthma, Allergic airway disease, Influenza, Streptococcus pneumoniae, Co-infection
Background
The global prevalence of individuals with asthma is increasing, with 300 million presently suffering and an additional 100 million new incidences predicted by 2025 (Nunes et al., 2017). Because of the altered immune system, asthmatic individuals are believed to have an increased risk of susceptibility to influenza infection. Seasonal and pandemic influenza infection can result in concurrent bacterial infection which can lead to airway respiratory distress syndrome, a potentially life-threatening condition (Gilca et al., 2011). Whether or not asthmatics are more susceptible and have reduced protective anti-influenza immune responses, is controversial. During the recent 2009 H1N1 pandemic, asthmatics were more likely to be hospitalized due to influenza. However, clinical data also suggest that asthmatics were less likely to die or require ICU admission than those without asthma. The majority of deaths during influenza pandemics are not caused by the viral infection per se, but instead, are due to complications from secondary bacterial infections (Morens et al., 2008; MacIntyre et al., 2018). We previously reported that mice with AAD are resistant to a single infection with influenza virus or S. pneumoniae (Furuya et al., 2015; Sanfilippo et al., 2015). However, there was no murine model that addressed the influence of allergic airway disease (AAD) on immunity to influenza virus and bacterial co-infection. Thus, we have developed a triple challenge model in mice to test the hypothesis that asthmatics are protected from severe influenza because they are less likely to develop severe secondary bacterial pneumonia (Roberts et al., 2019).
Materials and Reagents
Equipment
Procedure
Recipes
Acknowledgments
An abbreviated protocol was previously published in Roberts et al. (2019). Y. F. was supported by the American Lung Association Biomedical Research Grant (RG341974) and is supported by American Heart Association Scientist Development Grant (17SDG33630188 ) and NIH (1R56AI146434-01 ).
Competing interests
We do not have any conflict of interest.
Ethics
Animal care and experimental protocols were performed in accordance with the NIH Guide for the Care and Use of Laboratory Animals and were approved by the Institutional Animal Care and Use Committee at Albany Medical College (protocol number 17-03006, 05/19/2017-05/19/2020).
References
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