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Gr1(int)CD11b+ myeloid-derived suppressor cells in Mycobacterium tuberculosis infection.

Obregón-Henao A, Henao-Tamayo M, Orme IM, Ordway DJ - PLoS ONE (2013)

Bottom Line: Both populations of Gr1(+)CD11b(+) cells expressed high levels of arginase-1, and IL-17, additional markers of myeloid derived suppressor cells.Our results showed that both Gr1(hi) and Gr1(int) cells were able to induce activation and proliferation of CD4+ T cells.However this response was reduced as the ratio of CD4(+) T to Gr1(+) cells increased.

View Article: PubMed Central - PubMed

Affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America.

ABSTRACT

Background: Tuberculosis is one of the world's leading killers, stealing 1.4 million lives and causing 8.7 million new and relapsed infections in 2011. The only vaccine against tuberculosis is BCG which demonstrates variable efficacy in adults worldwide. Human infection with Mycobacterium tuberculosis results in the influx of inflammatory cells to the lung in an attempt to wall off bacilli by forming a granuloma. Gr1(int)CD11b(+) cells are called myeloid-derived suppressor cells (MDSC) and play a major role in regulation of inflammation in many pathological conditions. Although MDSC have been described primarily in cancer their function in tuberculosis remains unknown. During M. tuberculosis infection it is crucial to understand the function of cells involved in the regulation of inflammation during granuloma formation. Understanding their relative impact on the bacilli and other cellular phenotypes is necessary for future vaccine and drug design.

Methodology/principal findings: We compared the bacterial burden, lung pathology and Gr1(int)CD11b(+) myeloid-derived suppressor cell immune responses in M. tuberculosis infected NOS2-/-, RAG-/-, C3HeB/FeJ and C57/BL6 mice. Gr-1(+) cells could be found on the edges of necrotic lung lesions in NOS2-/-, RAG-/-, and C3HeB/FeJ, but were absent in wild-type mice. Both populations of Gr1(+)CD11b(+) cells expressed high levels of arginase-1, and IL-17, additional markers of myeloid derived suppressor cells. We then sorted the Gr1(hi) and Gr1(int) populations from M. tuberculosis infected NOS-/- mice and placed the sorted both Gr1(int) populations at different ratios with naïve or M. tuberculosis infected splenocytes and evaluated their ability to induce activation and proliferation of CD4+T cells. Our results showed that both Gr1(hi) and Gr1(int) cells were able to induce activation and proliferation of CD4+ T cells. However this response was reduced as the ratio of CD4(+) T to Gr1(+) cells increased. Our results illustrate a yet unrecognized interplay between Gr1(+) cells and CD4(+) T cells in tuberculosis.

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Two populations of CD11b+ cells based on FSC analysis.As suggested by FSC analysis, the increased number of CD11b+ cells present in NOS2 -/- mice could be separated in two populations based on cell size (A, B). Both populations of CD11b+ FSChigh cells and CD11b+FSClow cells are significantly increased in NOS2 -/- mice compared to C57/BL/6 mice (A, B). Contour plot is representative of day 45 after infection. FSC analysis clearly identified two CD11b+ populations in the lungs of NOS2 -/- mice (C). Results are expressed as the mean values fluorescence intensity (± SEM, n=5) in the Lung, Student t-test, *** p<0.001. Necrotic granulomas are only present in the lungs of NOS2 -/- mice (D). At different time points after infection, lungs were harvested and stained with H&E after fixation and paraffin embedding. For both murine strains, lesions are not present at day 15 after infection. Starting day 30, necrotic granulomas become evident in the lungs of NOS2 -/- mice but not WT C57BL/6. As observed at day 45 and 60, necrotic granulomas coalesce leading to severe lung consolidation at day 60 when most NOS2 -/- are moribund.
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pone-0080669-g002: Two populations of CD11b+ cells based on FSC analysis.As suggested by FSC analysis, the increased number of CD11b+ cells present in NOS2 -/- mice could be separated in two populations based on cell size (A, B). Both populations of CD11b+ FSChigh cells and CD11b+FSClow cells are significantly increased in NOS2 -/- mice compared to C57/BL/6 mice (A, B). Contour plot is representative of day 45 after infection. FSC analysis clearly identified two CD11b+ populations in the lungs of NOS2 -/- mice (C). Results are expressed as the mean values fluorescence intensity (± SEM, n=5) in the Lung, Student t-test, *** p<0.001. Necrotic granulomas are only present in the lungs of NOS2 -/- mice (D). At different time points after infection, lungs were harvested and stained with H&E after fixation and paraffin embedding. For both murine strains, lesions are not present at day 15 after infection. Starting day 30, necrotic granulomas become evident in the lungs of NOS2 -/- mice but not WT C57BL/6. As observed at day 45 and 60, necrotic granulomas coalesce leading to severe lung consolidation at day 60 when most NOS2 -/- are moribund.

Mentions: In contrast to C57BL/6, flow cytometric analysis clearly identified two CD11b+ populations in the lungs of M. tuberculosis infected NOS2 -/- mice after 30 days of infection (Figure 2A, B). The populations of GD11bhigh and CD11blow cells significantly differed in mean fluorescence intensity (MFI) suggested by the difference in CD11b+ verses FSC (Figure 2C). Interestingly, these two CD11b+ populations also differed in the degree of Gr1 expression: high Gr1 MFI was observed for CD11b+ FSChigh, whereas CD11b+ FSClow cells had intermediate Gr1 MFI (Figure 3 A, B). The increased expression of Gr-1int CD11b+ FSClow population in the NOS2-/- mice was associated with the increase in lung pathology present during chronic disease on days 45 and 60 (Figure 2D).


Gr1(int)CD11b+ myeloid-derived suppressor cells in Mycobacterium tuberculosis infection.

Obregón-Henao A, Henao-Tamayo M, Orme IM, Ordway DJ - PLoS ONE (2013)

Two populations of CD11b+ cells based on FSC analysis.As suggested by FSC analysis, the increased number of CD11b+ cells present in NOS2 -/- mice could be separated in two populations based on cell size (A, B). Both populations of CD11b+ FSChigh cells and CD11b+FSClow cells are significantly increased in NOS2 -/- mice compared to C57/BL/6 mice (A, B). Contour plot is representative of day 45 after infection. FSC analysis clearly identified two CD11b+ populations in the lungs of NOS2 -/- mice (C). Results are expressed as the mean values fluorescence intensity (± SEM, n=5) in the Lung, Student t-test, *** p<0.001. Necrotic granulomas are only present in the lungs of NOS2 -/- mice (D). At different time points after infection, lungs were harvested and stained with H&E after fixation and paraffin embedding. For both murine strains, lesions are not present at day 15 after infection. Starting day 30, necrotic granulomas become evident in the lungs of NOS2 -/- mice but not WT C57BL/6. As observed at day 45 and 60, necrotic granulomas coalesce leading to severe lung consolidation at day 60 when most NOS2 -/- are moribund.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815237&req=5

pone-0080669-g002: Two populations of CD11b+ cells based on FSC analysis.As suggested by FSC analysis, the increased number of CD11b+ cells present in NOS2 -/- mice could be separated in two populations based on cell size (A, B). Both populations of CD11b+ FSChigh cells and CD11b+FSClow cells are significantly increased in NOS2 -/- mice compared to C57/BL/6 mice (A, B). Contour plot is representative of day 45 after infection. FSC analysis clearly identified two CD11b+ populations in the lungs of NOS2 -/- mice (C). Results are expressed as the mean values fluorescence intensity (± SEM, n=5) in the Lung, Student t-test, *** p<0.001. Necrotic granulomas are only present in the lungs of NOS2 -/- mice (D). At different time points after infection, lungs were harvested and stained with H&E after fixation and paraffin embedding. For both murine strains, lesions are not present at day 15 after infection. Starting day 30, necrotic granulomas become evident in the lungs of NOS2 -/- mice but not WT C57BL/6. As observed at day 45 and 60, necrotic granulomas coalesce leading to severe lung consolidation at day 60 when most NOS2 -/- are moribund.
Mentions: In contrast to C57BL/6, flow cytometric analysis clearly identified two CD11b+ populations in the lungs of M. tuberculosis infected NOS2 -/- mice after 30 days of infection (Figure 2A, B). The populations of GD11bhigh and CD11blow cells significantly differed in mean fluorescence intensity (MFI) suggested by the difference in CD11b+ verses FSC (Figure 2C). Interestingly, these two CD11b+ populations also differed in the degree of Gr1 expression: high Gr1 MFI was observed for CD11b+ FSChigh, whereas CD11b+ FSClow cells had intermediate Gr1 MFI (Figure 3 A, B). The increased expression of Gr-1int CD11b+ FSClow population in the NOS2-/- mice was associated with the increase in lung pathology present during chronic disease on days 45 and 60 (Figure 2D).

Bottom Line: Both populations of Gr1(+)CD11b(+) cells expressed high levels of arginase-1, and IL-17, additional markers of myeloid derived suppressor cells.Our results showed that both Gr1(hi) and Gr1(int) cells were able to induce activation and proliferation of CD4+ T cells.However this response was reduced as the ratio of CD4(+) T to Gr1(+) cells increased.

View Article: PubMed Central - PubMed

Affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America.

ABSTRACT

Background: Tuberculosis is one of the world's leading killers, stealing 1.4 million lives and causing 8.7 million new and relapsed infections in 2011. The only vaccine against tuberculosis is BCG which demonstrates variable efficacy in adults worldwide. Human infection with Mycobacterium tuberculosis results in the influx of inflammatory cells to the lung in an attempt to wall off bacilli by forming a granuloma. Gr1(int)CD11b(+) cells are called myeloid-derived suppressor cells (MDSC) and play a major role in regulation of inflammation in many pathological conditions. Although MDSC have been described primarily in cancer their function in tuberculosis remains unknown. During M. tuberculosis infection it is crucial to understand the function of cells involved in the regulation of inflammation during granuloma formation. Understanding their relative impact on the bacilli and other cellular phenotypes is necessary for future vaccine and drug design.

Methodology/principal findings: We compared the bacterial burden, lung pathology and Gr1(int)CD11b(+) myeloid-derived suppressor cell immune responses in M. tuberculosis infected NOS2-/-, RAG-/-, C3HeB/FeJ and C57/BL6 mice. Gr-1(+) cells could be found on the edges of necrotic lung lesions in NOS2-/-, RAG-/-, and C3HeB/FeJ, but were absent in wild-type mice. Both populations of Gr1(+)CD11b(+) cells expressed high levels of arginase-1, and IL-17, additional markers of myeloid derived suppressor cells. We then sorted the Gr1(hi) and Gr1(int) populations from M. tuberculosis infected NOS-/- mice and placed the sorted both Gr1(int) populations at different ratios with naïve or M. tuberculosis infected splenocytes and evaluated their ability to induce activation and proliferation of CD4+T cells. Our results showed that both Gr1(hi) and Gr1(int) cells were able to induce activation and proliferation of CD4+ T cells. However this response was reduced as the ratio of CD4(+) T to Gr1(+) cells increased. Our results illustrate a yet unrecognized interplay between Gr1(+) cells and CD4(+) T cells in tuberculosis.

Show MeSH
Related in: MedlinePlus