tetano
Editor, Senior Moderator
J Virol. 2014 Apr 16. [Epub ahead of print]
ENHANCED VIRAL REPLICATION AND MODULATED INNATE IMMUNE RESPONSES IN INFANT AIRWAY EPITHELIUM FOLLOWING H1N1 INFECTION.
Clay CC1, Reader JR, Gerriets JE, Wang TT, Harrod KS, Miller LA.
Author information
Abstract
Influenza is the cause of significant morbidity and mortality in pediatric populations. The contribution of pulmonary host defense mechanisms to viral respiratory infection susceptibility in very young children is poorly understood. As a surrogate to compare mucosal immune responses for infant and adult lung, rhesus monkey primary airway epithelial cell cultures were infected with pandemic influenza A/H1N1 in vitro. Virus replication, cytokine secretion, cell viability and type I interferon (IFN) pathway PCR array profiles were evaluated for both infant and adult cultures. In comparison with adult cultures, infants showed significantly increased levels of H1N1 replication, reduced IFN-alpha protein synthesis and no difference in cell death following infection. Age-dependent differences in expression of multiple genes associated with the type I IFN pathway were observed in H1N1-infected cultures. To investigate the pulmonary and systemic response to H1N1 infection in early life, infant monkeys were inoculated with H1N1 by upper airway administration. Animals were monitored over a 14 day period for virus and parameters of inflammation. High H1N1 titers were recovered from airways at day 1, with viral RNA remaining detectable until day 9 post infection. Despite viral clearance, bronchiolitis and alveolitis persisted at day 14 post infection; histopathologic analysis revealed alveolar septal thickening and intermittent type II pneumocyte hyperplasia. Our overall findings are consistent with the known susceptibility of respiratory virus infection in pediatric populations and suggest that intrinsic developmental differences in airway epithelial cell immune function may contribute to the limited efficacy of host defense during early childhood.
IMPORTANCE:
To the best of our knowledge, this study represents the first report of intrinsic developmental differences in infant airway epithelial cells that may contribute to increased susceptibility of the host to respiratory virus infections. Despite the global burden of influenza, there are currently no vaccine formulations approved for children less than 6 months of age. Given the challenges of conducting experimental studies involving pediatric patients, rhesus monkeys are an ideal laboratory animal model to investigate the maturation of pulmonary mucosal immune mechanisms during early life because they are most similar to humans with regard to postnatal maturation of lung structure and the immune system. Thus, our findings are highly relevant to translational medicine and these data may ultimately lead to novel approaches that enhance airway immunity in the very young.
PMID:
24741104
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24741104
ENHANCED VIRAL REPLICATION AND MODULATED INNATE IMMUNE RESPONSES IN INFANT AIRWAY EPITHELIUM FOLLOWING H1N1 INFECTION.
Clay CC1, Reader JR, Gerriets JE, Wang TT, Harrod KS, Miller LA.
Author information
Abstract
Influenza is the cause of significant morbidity and mortality in pediatric populations. The contribution of pulmonary host defense mechanisms to viral respiratory infection susceptibility in very young children is poorly understood. As a surrogate to compare mucosal immune responses for infant and adult lung, rhesus monkey primary airway epithelial cell cultures were infected with pandemic influenza A/H1N1 in vitro. Virus replication, cytokine secretion, cell viability and type I interferon (IFN) pathway PCR array profiles were evaluated for both infant and adult cultures. In comparison with adult cultures, infants showed significantly increased levels of H1N1 replication, reduced IFN-alpha protein synthesis and no difference in cell death following infection. Age-dependent differences in expression of multiple genes associated with the type I IFN pathway were observed in H1N1-infected cultures. To investigate the pulmonary and systemic response to H1N1 infection in early life, infant monkeys were inoculated with H1N1 by upper airway administration. Animals were monitored over a 14 day period for virus and parameters of inflammation. High H1N1 titers were recovered from airways at day 1, with viral RNA remaining detectable until day 9 post infection. Despite viral clearance, bronchiolitis and alveolitis persisted at day 14 post infection; histopathologic analysis revealed alveolar septal thickening and intermittent type II pneumocyte hyperplasia. Our overall findings are consistent with the known susceptibility of respiratory virus infection in pediatric populations and suggest that intrinsic developmental differences in airway epithelial cell immune function may contribute to the limited efficacy of host defense during early childhood.
IMPORTANCE:
To the best of our knowledge, this study represents the first report of intrinsic developmental differences in infant airway epithelial cells that may contribute to increased susceptibility of the host to respiratory virus infections. Despite the global burden of influenza, there are currently no vaccine formulations approved for children less than 6 months of age. Given the challenges of conducting experimental studies involving pediatric patients, rhesus monkeys are an ideal laboratory animal model to investigate the maturation of pulmonary mucosal immune mechanisms during early life because they are most similar to humans with regard to postnatal maturation of lung structure and the immune system. Thus, our findings are highly relevant to translational medicine and these data may ultimately lead to novel approaches that enhance airway immunity in the very young.
PMID:
24741104
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24741104