Limits...
Interleukin-12p40 modulates human metapneumovirus-induced pulmonary disease in an acute mouse model of infection.

Chakraborty K, Zhou Z, Wakamatsu N, Guerrero-Plata A - PLoS ONE (2012)

Bottom Line: IL-12p40, a known important mediator in limiting lung inflammation, is induced by hMPV and its production is sustained after the resolution phase of infection suggesting that this cytokine plays a role in the immune response against hMPV.However, hMPV infection in these mice does not have an effect on viral replication.These results identify an important regulatory role of IL-12p40 in hMPV infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
The mechanisms that regulate the host immune response induced by human metapneumovirus (hMPV), a newly-recognized member of the Paramyxoviridae family, are largely unknown. Cytokines play an important role in modulating inflammatory responses during viral infections. IL-12p40, a known important mediator in limiting lung inflammation, is induced by hMPV and its production is sustained after the resolution phase of infection suggesting that this cytokine plays a role in the immune response against hMPV. In this work, we demonstrated that in mice deficient in IL-12p40, hMPV infection induced an exacerbated pulmonary inflammatory response and mucus production, altered cytokine response, and decreased lung function. However, hMPV infection in these mice does not have an effect on viral replication. These results identify an important regulatory role of IL-12p40 in hMPV infection.

Show MeSH

Related in: MedlinePlus

Disease severity and lung viral replication in the absence of IL-12p40.Mice (7–10 week old) were inoculated with PBS (mock) or infected i.n. with 5×106 PFU of hMPV. (A) Bronchoalveolar lavage was collected at different time points from mock, hMPV-infected and UV-inactivated hMPV-infected mice and IL-12p40 was determined by Bio-Plex Pro™ assay. n = 5 mice/group. (B) Mice were monitored daily and body weight was calculated based on the original weight before the infection. n = 3 mice/group. (C) Total lung tissue was harvested at different time points and lung infectious viral particles were titrated on LLC-MK2 cell monolayers by methylcellulose plaque assay. n = 4 mice/group. (D) hMPV N gene expression in the lung of infected mice was determined by real-time RT-PCR. n = 3 mice/group. *P<0.05, **P<0.01, ***P<0.001.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3351396&req=5

pone-0037173-g001: Disease severity and lung viral replication in the absence of IL-12p40.Mice (7–10 week old) were inoculated with PBS (mock) or infected i.n. with 5×106 PFU of hMPV. (A) Bronchoalveolar lavage was collected at different time points from mock, hMPV-infected and UV-inactivated hMPV-infected mice and IL-12p40 was determined by Bio-Plex Pro™ assay. n = 5 mice/group. (B) Mice were monitored daily and body weight was calculated based on the original weight before the infection. n = 3 mice/group. (C) Total lung tissue was harvested at different time points and lung infectious viral particles were titrated on LLC-MK2 cell monolayers by methylcellulose plaque assay. n = 4 mice/group. (D) hMPV N gene expression in the lung of infected mice was determined by real-time RT-PCR. n = 3 mice/group. *P<0.05, **P<0.01, ***P<0.001.

Mentions: In order to determine the role of IL-12p40 in the regulation of disease severity during hMPV infection, the production of IL-12p40, body weight loss, and lung viral replication were assessed. WT C57BL/6 and IL-12p40-KO mice were infected intranasally ( i.n.) with hMPV (5×106 PFU/mouse), monitored daily and bronchoalveolar lavage (BAL) fluid was analyzed at different time points after infection. As shown in Fig. 1A, hMPV induced the release of IL-12p40 in BAL samples of C57BL/6 mice as early as day 1 after infection and the production of this cytokine remained sustained beyond the resolution of the infection (day 11, latest time point tested). Moreover, the induction of IL-12p40 was dependent of viral replication since UV inactivation of the virus resulted in a significant reduction of the production of the cytokine (Fig. 1A). In addition, the absence of IL-12p40 exacerbated the disease severity of hMPV-infected mice. As shown in Fig. 1B, IL-12p40-KO mice exhibited more body weight loss (26%) than WT mice (8%) at the peak of the clinical disease at day 6. Furthermore, a delayed recovery to baseline weight in IL-12p40-KO mice was also observed since those mice reached similar values to mock-infected mice at day 15 after infection versus at day 10 in the WT group (Fig. 1B). To determine whether the exacerbation of body weight loss was related to an altered viral replication in the deficient mice, hMPV-infected IL-12p40-KO and WT mice were sacrificed at day 1, 3, 5, and 7 after infection and total lung tissue was collected to determine virus replication by plaque assay. Resulting viral titers showed that hMPV replicates in the lungs of WT and IL-12p40-KO mice with a peak of viral titer at day 5 after infection. However, no difference between both groups of animals was observed in any time point tested (Fig. 1C). Differences in viral replication were confirmed by the analysis of viral gene expression in the lungs at day 5 after infection (peak of viral replication), where the virus was detected in the infected animals, but in similar amounts when compared WT and IL-2p40-KO mice (Fig. 1D).


Interleukin-12p40 modulates human metapneumovirus-induced pulmonary disease in an acute mouse model of infection.

Chakraborty K, Zhou Z, Wakamatsu N, Guerrero-Plata A - PLoS ONE (2012)

Disease severity and lung viral replication in the absence of IL-12p40.Mice (7–10 week old) were inoculated with PBS (mock) or infected i.n. with 5×106 PFU of hMPV. (A) Bronchoalveolar lavage was collected at different time points from mock, hMPV-infected and UV-inactivated hMPV-infected mice and IL-12p40 was determined by Bio-Plex Pro™ assay. n = 5 mice/group. (B) Mice were monitored daily and body weight was calculated based on the original weight before the infection. n = 3 mice/group. (C) Total lung tissue was harvested at different time points and lung infectious viral particles were titrated on LLC-MK2 cell monolayers by methylcellulose plaque assay. n = 4 mice/group. (D) hMPV N gene expression in the lung of infected mice was determined by real-time RT-PCR. n = 3 mice/group. *P<0.05, **P<0.01, ***P<0.001.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3351396&req=5

pone-0037173-g001: Disease severity and lung viral replication in the absence of IL-12p40.Mice (7–10 week old) were inoculated with PBS (mock) or infected i.n. with 5×106 PFU of hMPV. (A) Bronchoalveolar lavage was collected at different time points from mock, hMPV-infected and UV-inactivated hMPV-infected mice and IL-12p40 was determined by Bio-Plex Pro™ assay. n = 5 mice/group. (B) Mice were monitored daily and body weight was calculated based on the original weight before the infection. n = 3 mice/group. (C) Total lung tissue was harvested at different time points and lung infectious viral particles were titrated on LLC-MK2 cell monolayers by methylcellulose plaque assay. n = 4 mice/group. (D) hMPV N gene expression in the lung of infected mice was determined by real-time RT-PCR. n = 3 mice/group. *P<0.05, **P<0.01, ***P<0.001.
Mentions: In order to determine the role of IL-12p40 in the regulation of disease severity during hMPV infection, the production of IL-12p40, body weight loss, and lung viral replication were assessed. WT C57BL/6 and IL-12p40-KO mice were infected intranasally ( i.n.) with hMPV (5×106 PFU/mouse), monitored daily and bronchoalveolar lavage (BAL) fluid was analyzed at different time points after infection. As shown in Fig. 1A, hMPV induced the release of IL-12p40 in BAL samples of C57BL/6 mice as early as day 1 after infection and the production of this cytokine remained sustained beyond the resolution of the infection (day 11, latest time point tested). Moreover, the induction of IL-12p40 was dependent of viral replication since UV inactivation of the virus resulted in a significant reduction of the production of the cytokine (Fig. 1A). In addition, the absence of IL-12p40 exacerbated the disease severity of hMPV-infected mice. As shown in Fig. 1B, IL-12p40-KO mice exhibited more body weight loss (26%) than WT mice (8%) at the peak of the clinical disease at day 6. Furthermore, a delayed recovery to baseline weight in IL-12p40-KO mice was also observed since those mice reached similar values to mock-infected mice at day 15 after infection versus at day 10 in the WT group (Fig. 1B). To determine whether the exacerbation of body weight loss was related to an altered viral replication in the deficient mice, hMPV-infected IL-12p40-KO and WT mice were sacrificed at day 1, 3, 5, and 7 after infection and total lung tissue was collected to determine virus replication by plaque assay. Resulting viral titers showed that hMPV replicates in the lungs of WT and IL-12p40-KO mice with a peak of viral titer at day 5 after infection. However, no difference between both groups of animals was observed in any time point tested (Fig. 1C). Differences in viral replication were confirmed by the analysis of viral gene expression in the lungs at day 5 after infection (peak of viral replication), where the virus was detected in the infected animals, but in similar amounts when compared WT and IL-2p40-KO mice (Fig. 1D).

Bottom Line: IL-12p40, a known important mediator in limiting lung inflammation, is induced by hMPV and its production is sustained after the resolution phase of infection suggesting that this cytokine plays a role in the immune response against hMPV.However, hMPV infection in these mice does not have an effect on viral replication.These results identify an important regulatory role of IL-12p40 in hMPV infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
The mechanisms that regulate the host immune response induced by human metapneumovirus (hMPV), a newly-recognized member of the Paramyxoviridae family, are largely unknown. Cytokines play an important role in modulating inflammatory responses during viral infections. IL-12p40, a known important mediator in limiting lung inflammation, is induced by hMPV and its production is sustained after the resolution phase of infection suggesting that this cytokine plays a role in the immune response against hMPV. In this work, we demonstrated that in mice deficient in IL-12p40, hMPV infection induced an exacerbated pulmonary inflammatory response and mucus production, altered cytokine response, and decreased lung function. However, hMPV infection in these mice does not have an effect on viral replication. These results identify an important regulatory role of IL-12p40 in hMPV infection.

Show MeSH
Related in: MedlinePlus