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Depletion of Neutrophils Exacerbates the Early Inflammatory Immune Response in Lungs of Mice Infected with Paracoccidioides brasiliensis

View Article: PubMed Central - PubMed

ABSTRACT

Neutrophils predominate during the acute phase of the Paracoccidioides brasiliensis infection. Herein, we determined the role of the neutrophil during the early stages of experimental pulmonary paracoccidioidomycosis using a monoclonal antibody (mAb) specific for neutrophils. Male BALB/c mice were inoculated intranasally with 1.5 × 106 or 2 × 106 P. brasiliensis yeast cells. The mAb was administered 24 h before infection, followed by doses every 48 h until mice were sacrificed. Survival time was evaluated and mice were sacrificed at 48 h and 96 h after inoculation to assess cellularity, fungal load, cytokine/chemokine levels, and histopathological analysis. Neutrophils from mAb-treated mice were efficiently depleted (99.04%). Eighty percent of the mice treated with the mAb and infected with 1.5 × 106 yeast cells died during the first two weeks after infection. When mice were treated and infected with 2 × 106 yeast cells, 100% of them succumbed by the first week after infection. During the acute inflammatory response significant increases in numbers of eosinophils, fungal load and levels of proinflammatory cytokines/chemokines were observed in the mAb-treated mice. We also confirmed that neutrophils are an important source of IFN-γ and IL-17. These results indicate that neutrophils are essential for protection as well as being important for regulating the early inflammatory immune response in experimental pulmonary paracoccidioidomycosis.

No MeSH data available.


Related in: MedlinePlus

Neutrophils are an important source of IFN-γ and IL-17. BALB/c mice were intranasally inoculated with PBS or 1.5 × 106 P. brasiliensis (Pb18) yeast cells and analyzed during the acute phase of P. brasiliensis infection (96 h postchallenge). (a) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (b) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells per lung. (c) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (d) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells per lung. Data shown represent median and IQR (n = 4-5 mice/group; representative of two independent experiments). ∗P < 0.05 comparing infected versus control mice. PBS, control mice; Pb18, infected mice.
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fig6: Neutrophils are an important source of IFN-γ and IL-17. BALB/c mice were intranasally inoculated with PBS or 1.5 × 106 P. brasiliensis (Pb18) yeast cells and analyzed during the acute phase of P. brasiliensis infection (96 h postchallenge). (a) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (b) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells per lung. (c) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (d) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells per lung. Data shown represent median and IQR (n = 4-5 mice/group; representative of two independent experiments). ∗P < 0.05 comparing infected versus control mice. PBS, control mice; Pb18, infected mice.

Mentions: In other sets of experiments, we confirmed that neutrophils are a source of two important cytokines such as IFN-γ, which is necessary to activate macrophages and mount an effective antifungal response, and IL-17 considered one of the most important proinflammatory cytokines. Thus, near to 60% of the total leukocytes (CD45+)/IFN-γ producing cells corresponded to neutrophils (Figures 6(a)-6(b)). In the case of IL-17, neutrophils accounted for 73% of the total leukocytes (CD45+)/IL-17 producing cells (Figures 6(c)-6(d)).


Depletion of Neutrophils Exacerbates the Early Inflammatory Immune Response in Lungs of Mice Infected with Paracoccidioides brasiliensis
Neutrophils are an important source of IFN-γ and IL-17. BALB/c mice were intranasally inoculated with PBS or 1.5 × 106 P. brasiliensis (Pb18) yeast cells and analyzed during the acute phase of P. brasiliensis infection (96 h postchallenge). (a) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (b) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells per lung. (c) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (d) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells per lung. Data shown represent median and IQR (n = 4-5 mice/group; representative of two independent experiments). ∗P < 0.05 comparing infected versus control mice. PBS, control mice; Pb18, infected mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig6: Neutrophils are an important source of IFN-γ and IL-17. BALB/c mice were intranasally inoculated with PBS or 1.5 × 106 P. brasiliensis (Pb18) yeast cells and analyzed during the acute phase of P. brasiliensis infection (96 h postchallenge). (a) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (b) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IFN-γ-producing cells per lung. (c) Representative flow cytometry contour plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells subpopulations at 96 h after infection are shown. Numbers inside the gates indicate the mean percentages of the gated subsets. (d) Bar plots of CD45+- and neutrophils- (CD45+/CD11b+/Gr1+/Ly6G+-) IL-17-producing cells per lung. Data shown represent median and IQR (n = 4-5 mice/group; representative of two independent experiments). ∗P < 0.05 comparing infected versus control mice. PBS, control mice; Pb18, infected mice.
Mentions: In other sets of experiments, we confirmed that neutrophils are a source of two important cytokines such as IFN-γ, which is necessary to activate macrophages and mount an effective antifungal response, and IL-17 considered one of the most important proinflammatory cytokines. Thus, near to 60% of the total leukocytes (CD45+)/IFN-γ producing cells corresponded to neutrophils (Figures 6(a)-6(b)). In the case of IL-17, neutrophils accounted for 73% of the total leukocytes (CD45+)/IL-17 producing cells (Figures 6(c)-6(d)).

View Article: PubMed Central - PubMed

ABSTRACT

Neutrophils predominate during the acute phase of the Paracoccidioides brasiliensis infection. Herein, we determined the role of the neutrophil during the early stages of experimental pulmonary paracoccidioidomycosis using a monoclonal antibody (mAb) specific for neutrophils. Male BALB/c mice were inoculated intranasally with 1.5 &times; 106 or 2 &times; 106 P. brasiliensis yeast cells. The mAb was administered 24&thinsp;h before infection, followed by doses every 48&thinsp;h until mice were sacrificed. Survival time was evaluated and mice were sacrificed at 48&thinsp;h and 96&thinsp;h after inoculation to assess cellularity, fungal load, cytokine/chemokine levels, and histopathological analysis. Neutrophils from mAb-treated mice were efficiently depleted (99.04%). Eighty percent of the mice treated with the mAb and infected with 1.5 &times; 106 yeast cells died during the first two weeks after infection. When mice were treated and infected with 2 &times; 106 yeast cells, 100% of them succumbed by the first week after infection. During the acute inflammatory response significant increases in numbers of eosinophils, fungal load and levels of proinflammatory cytokines/chemokines were observed in the mAb-treated mice. We also confirmed that neutrophils are an important source of IFN-&gamma; and IL-17. These results indicate that neutrophils are essential for protection as well as being important for regulating the early inflammatory immune response in experimental pulmonary paracoccidioidomycosis.

No MeSH data available.


Related in: MedlinePlus