Low CCR7-Mediated Migration of Human Monocyte Derived Dendritic Cells in Response to Human Respiratory Syncytial Virus and Human Metapneumovirus

Abstract Background The effect of SARS-CoV-2 on existing respiratory pathogens in circulation remains uncertain. This study aimed to assess the impact of SARS-CoV-2 on the prevalence of respiratory pathogens among hospitalized children. Methods This study enrolled hospitalized children with acute respiratory infections in Shenzhen Children’s Hospital from September to December 2019 (before the COVID-19 epidemic) and those from September to December 2020 (during the COVID-19 epidemic). Nasopharyngeal swabs were collected, and respiratory pathogens were detected using multiplex PCR. The absolute case number and detection rates of 11 pathogens were collected and analyzed. Results A total of 5696 children with respiratory tract infection received multiplex PCR examination for respiratory pathogens: 2298 from September to December 2019 and 3398 from September to December 2020. At least one pathogen was detected in 1850 (80.5%) patients in 2019, and in 2380 (70.0%) patients in 2020; the detection rate in 2020 was significantly lower than that in 2019.The Influenza A (InfA) detection rate was 5.6% in 2019, but 0% in 2020. The detection rates of Mycoplasma pneumoniae, Human adenovirus, and Human rhinovirus also decreased from 20% (460), 8.9% (206), and 41.8% (961) in 2019 to 1.0% (37), 2.1% (77), and 25.6% (873) in 2020, respectively. In contrast, the detection rates of Human respiratory syncytial virus, Human parainfluenza virus, and Human metapneumovirus increased from 6.6% (153), 9.9% (229), and 0.5% (12) in 2019 to 25.6% (873), 15.5% (530), and 7.2% (247) in 2020, respectively (p < 0.0001). Conclusions Successful containment of seasonal influenza as a result of COVID-19 control measures will ensure we are better equipped to deal with future outbreaks of both influenza and COVID-19.Caused by virus competition, the detection rates of Human respiratory syncytial virus, Human parainfluenza virus, and Human metapneumovirus increased in Shenzhen,that reminds us we need to take further monitoring and preventive measures in the next epidemic season.

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Priming of the Respiratory Tract with ImmunobioticLactobacillus plantarumLimits Infection of Alveolar Macrophages with Recombinant Pneumonia Virus of Mice (rK2-PVM)

Journal of Virology ◽

10.1128/jvi.02279-15 ◽

2015 ◽

Vol 90 (2) ◽

pp. 979-991 ◽

Cited By ~ 9

Author(s):

Kimberly D. Dyer ◽

Rebecca A. Drummond ◽

Tyler A. Rice ◽

Caroline M. Percopo ◽

Todd A. Brenner ◽

...

Keyword(s):

Dendritic Cells ◽

Respiratory Syncytial Virus ◽

Respiratory Tract ◽

Alveolar Macrophages ◽

Human Respiratory Syncytial Virus ◽

Content Type ◽

Cellular Basis ◽

Syncytial Virus ◽

Insight Into

ABSTRACTPneumonia virus of mice (PVM) is a natural rodent pathogen that replicates in bronchial epithelial cells and reproduces many clinical and pathological features of the more severe forms of disease associated with human respiratory syncytial virus. In order to track virus-target cell interactions during acute infectionin vivo, we developed rK2-PVM, bacterial artificial chromosome-based recombinant PVM strain J3666 that incorporates the fluorescent tag monomeric Katushka 2 (mKATE2). The rK2-PVM pathogen promotes lethal infection in BALB/c mice and elicits characteristic cytokine production and leukocyte recruitment to the lung parenchyma. Using recombinant virus, we demonstrate for the first time PVM infection of both dendritic cells (DCs; CD11c+major histocompatibility complex class II+) and alveolar macrophages (AMs; CD11c+sialic acid-binding immunoglobulin-like lectin F+)in vivoand likewise detect mKATE2+DCs in mediastinal lymph nodes from infected mice. AMs support both active virus replication and production of infectious virions. Furthermore, we report that priming of the respiratory tract with immunobioticLactobacillus plantarum, a regimen that results in protection against the lethal inflammatory sequelae of acute respiratory virus infection, resulted in differential recruitment of neutrophils, DCs, and lymphocytes to the lungs in response to rK2-PVM and a reduction from ∼40% to <10% mKATE2+AMs in association with a 2-log drop in the release of infectious virions. In contrast, AMs fromL. plantarum-primed mice challenged with virusex vivoexhibited no differential susceptibility to rK2-PVM. Although the mechanisms underlyingLactobacillus-mediated viral suppression remain to be fully elucidated, this study provides insight into the cellular basis of this response.IMPORTANCEPneumonia virus of mice (PVM) is a natural mouse pathogen that serves as a model for severe human respiratory syncytial virus disease. We have developed a fully functional recombinant PVM strain with a fluorescent reporter protein (rK2-PVM) that permits us to track infection of target cellsin vivo. With rK2-PVM, we demonstrate infection of leukocytes in the lung, notably, dendritic cells and alveolar macrophages. Alveolar macrophages undergo productive infection and release infectious virions. We have shown previously that administration of immunobioticLactobacillusdirectly to the respiratory mucosa protects mice from the lethal sequelae of PVM infection in association with profound suppression of the virus-induced inflammatory response. We show here thatLactobacillusadministration also limits infection of leukocytesin vivoand results in diminished release of infectious virions from alveolar macrophages. This is the first study to provide insight into the cellular basis of the antiviral impact of immunobioticL. plantarum.

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