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Induced bronchus-associated lymphoid tissue serves as a general priming site for T cells and is maintained by dendritic cells.

Halle S, Dujardin HC, Bakocevic N, Fleige H, Danzer H, Willenzon S, Suezer Y, Hämmerling G, Garbi N, Sutter G, Worbs T, Förster R - J. Exp. Med. (2009)

Bottom Line: After intratracheal application, in vitro-differentiated, antigen-loaded DCs rapidly migrate into preformed BALT and efficiently activate antigen-specific T cells, as revealed by two-photon microscopy.Furthermore, the lung-specific depletion of DCs in mice that express the diphtheria toxin receptor under the control of the CD11c promoter interferes with BALT maintenance.Collectively, these data identify BALT as tertiary lymphoid structures supporting the efficient priming of T cell responses directed against unrelated airborne antigens while crucially requiring DCs for its sustained presence.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany.

ABSTRACT
Mucosal vaccination via the respiratory tract can elicit protective immunity in animal infection models, but the underlying mechanisms are still poorly understood. We show that a single intranasal application of the replication-deficient modified vaccinia virus Ankara, which is widely used as a recombinant vaccination vector, results in prominent induction of bronchus-associated lymphoid tissue (BALT). Although initial peribronchiolar infiltrations, characterized by the presence of dendritic cells (DCs) and few lymphocytes, can be found 4 d after virus application, organized lymphoid structures with segregated B and T cell zones are first observed at day 8. After intratracheal application, in vitro-differentiated, antigen-loaded DCs rapidly migrate into preformed BALT and efficiently activate antigen-specific T cells, as revealed by two-photon microscopy. Furthermore, the lung-specific depletion of DCs in mice that express the diphtheria toxin receptor under the control of the CD11c promoter interferes with BALT maintenance. Collectively, these data identify BALT as tertiary lymphoid structures supporting the efficient priming of T cell responses directed against unrelated airborne antigens while crucially requiring DCs for its sustained presence.

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Initial host cell tropism of MVA in the lung. Mice were i.n. infected with 107 IU MVA, and BAL cells were analyzed by flow cytometry. (A) GFP expression of DAPI− BAL cells 7 h after infection with MVA-GFP or MVA-WT. (B) GFP expression of BAL 0–72 h after i.n. infection with MVA-GFP (mean + SD; n = 2–3 mice/time point). (C and D) Expression of CD11c and MHCII on all (C) or GFP+ (D) DAPI− BAL cells 7 h after infection with MVA-GFP. (E) Immunohistology of lung sections 6 h after i.n. application of Cy5-labeled MVA using antibodies and dyes as indicated. (F) As in E, we obtained sections from lungs 30 min after MVA-Cy5 application. Bars, 25 µm. (G–I) FACS analysis of BAL cells 3 d after MVA-Cy5 application using antibodies and virus as indicated. (G and H) Gate on all DAPI− cells. (I) Gate on all DAPI− MVA-Cy5+ cells. The FACS plots and immunohistology shown are representative of three independent experiments, each with two to three mice analyzed per time point. *, P < 0.05; **, P < 0.01.
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fig2: Initial host cell tropism of MVA in the lung. Mice were i.n. infected with 107 IU MVA, and BAL cells were analyzed by flow cytometry. (A) GFP expression of DAPI− BAL cells 7 h after infection with MVA-GFP or MVA-WT. (B) GFP expression of BAL 0–72 h after i.n. infection with MVA-GFP (mean + SD; n = 2–3 mice/time point). (C and D) Expression of CD11c and MHCII on all (C) or GFP+ (D) DAPI− BAL cells 7 h after infection with MVA-GFP. (E) Immunohistology of lung sections 6 h after i.n. application of Cy5-labeled MVA using antibodies and dyes as indicated. (F) As in E, we obtained sections from lungs 30 min after MVA-Cy5 application. Bars, 25 µm. (G–I) FACS analysis of BAL cells 3 d after MVA-Cy5 application using antibodies and virus as indicated. (G and H) Gate on all DAPI− cells. (I) Gate on all DAPI− MVA-Cy5+ cells. The FACS plots and immunohistology shown are representative of three independent experiments, each with two to three mice analyzed per time point. *, P < 0.05; **, P < 0.01.

Mentions: To monitor productive MVA infection and viral gene expression in the lung, we used an MVA strain encoding an enhanced GFP (EGFP; Lehmann et al., 2009). Within 5–7 h after i.n. infection, high numbers of GFPbright cells could be detected in the bronchioalveolar lavage (BAL) of MVA-GFP–infected but not MVA-WT–infected animals (Fig. 2, A and B). Although up to 50% of all live cells in the BAL expressed GFP at 7 h after infection, only a very small proportion of cells were still GFP+ at 24 h after infection, and no GFP signals were detectable at later time points (Fig. 2 B). Because MVA cannot produce infectious virions in mammals (Ramírez et al., 2000), these data indicate that MVA infectivity is rapidly inactivated in vivo. Further analysis revealed that 65% of all BAL cells isolated 5–7 h after infection represented alveolar macrophages (AMs; CD11c+MHCII−; Fig. 2 C). More than 92% of all GFP+ cells showed this phenotype, with only 4% of all GFP+ cells being conventional DCs (CD11c+MHCII+; Fig. 2 D). Importantly, the analysis of single-cell suspensions prepared by enzymatic digestion of whole-lung tissue yielded largely identical results (unpublished data).


Induced bronchus-associated lymphoid tissue serves as a general priming site for T cells and is maintained by dendritic cells.

Halle S, Dujardin HC, Bakocevic N, Fleige H, Danzer H, Willenzon S, Suezer Y, Hämmerling G, Garbi N, Sutter G, Worbs T, Förster R - J. Exp. Med. (2009)

Initial host cell tropism of MVA in the lung. Mice were i.n. infected with 107 IU MVA, and BAL cells were analyzed by flow cytometry. (A) GFP expression of DAPI− BAL cells 7 h after infection with MVA-GFP or MVA-WT. (B) GFP expression of BAL 0–72 h after i.n. infection with MVA-GFP (mean + SD; n = 2–3 mice/time point). (C and D) Expression of CD11c and MHCII on all (C) or GFP+ (D) DAPI− BAL cells 7 h after infection with MVA-GFP. (E) Immunohistology of lung sections 6 h after i.n. application of Cy5-labeled MVA using antibodies and dyes as indicated. (F) As in E, we obtained sections from lungs 30 min after MVA-Cy5 application. Bars, 25 µm. (G–I) FACS analysis of BAL cells 3 d after MVA-Cy5 application using antibodies and virus as indicated. (G and H) Gate on all DAPI− cells. (I) Gate on all DAPI− MVA-Cy5+ cells. The FACS plots and immunohistology shown are representative of three independent experiments, each with two to three mice analyzed per time point. *, P < 0.05; **, P < 0.01.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2806625&req=5

fig2: Initial host cell tropism of MVA in the lung. Mice were i.n. infected with 107 IU MVA, and BAL cells were analyzed by flow cytometry. (A) GFP expression of DAPI− BAL cells 7 h after infection with MVA-GFP or MVA-WT. (B) GFP expression of BAL 0–72 h after i.n. infection with MVA-GFP (mean + SD; n = 2–3 mice/time point). (C and D) Expression of CD11c and MHCII on all (C) or GFP+ (D) DAPI− BAL cells 7 h after infection with MVA-GFP. (E) Immunohistology of lung sections 6 h after i.n. application of Cy5-labeled MVA using antibodies and dyes as indicated. (F) As in E, we obtained sections from lungs 30 min after MVA-Cy5 application. Bars, 25 µm. (G–I) FACS analysis of BAL cells 3 d after MVA-Cy5 application using antibodies and virus as indicated. (G and H) Gate on all DAPI− cells. (I) Gate on all DAPI− MVA-Cy5+ cells. The FACS plots and immunohistology shown are representative of three independent experiments, each with two to three mice analyzed per time point. *, P < 0.05; **, P < 0.01.
Mentions: To monitor productive MVA infection and viral gene expression in the lung, we used an MVA strain encoding an enhanced GFP (EGFP; Lehmann et al., 2009). Within 5–7 h after i.n. infection, high numbers of GFPbright cells could be detected in the bronchioalveolar lavage (BAL) of MVA-GFP–infected but not MVA-WT–infected animals (Fig. 2, A and B). Although up to 50% of all live cells in the BAL expressed GFP at 7 h after infection, only a very small proportion of cells were still GFP+ at 24 h after infection, and no GFP signals were detectable at later time points (Fig. 2 B). Because MVA cannot produce infectious virions in mammals (Ramírez et al., 2000), these data indicate that MVA infectivity is rapidly inactivated in vivo. Further analysis revealed that 65% of all BAL cells isolated 5–7 h after infection represented alveolar macrophages (AMs; CD11c+MHCII−; Fig. 2 C). More than 92% of all GFP+ cells showed this phenotype, with only 4% of all GFP+ cells being conventional DCs (CD11c+MHCII+; Fig. 2 D). Importantly, the analysis of single-cell suspensions prepared by enzymatic digestion of whole-lung tissue yielded largely identical results (unpublished data).

Bottom Line: After intratracheal application, in vitro-differentiated, antigen-loaded DCs rapidly migrate into preformed BALT and efficiently activate antigen-specific T cells, as revealed by two-photon microscopy.Furthermore, the lung-specific depletion of DCs in mice that express the diphtheria toxin receptor under the control of the CD11c promoter interferes with BALT maintenance.Collectively, these data identify BALT as tertiary lymphoid structures supporting the efficient priming of T cell responses directed against unrelated airborne antigens while crucially requiring DCs for its sustained presence.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Immunology, Hannover Medical School, 30625 Hannover, Germany.

ABSTRACT
Mucosal vaccination via the respiratory tract can elicit protective immunity in animal infection models, but the underlying mechanisms are still poorly understood. We show that a single intranasal application of the replication-deficient modified vaccinia virus Ankara, which is widely used as a recombinant vaccination vector, results in prominent induction of bronchus-associated lymphoid tissue (BALT). Although initial peribronchiolar infiltrations, characterized by the presence of dendritic cells (DCs) and few lymphocytes, can be found 4 d after virus application, organized lymphoid structures with segregated B and T cell zones are first observed at day 8. After intratracheal application, in vitro-differentiated, antigen-loaded DCs rapidly migrate into preformed BALT and efficiently activate antigen-specific T cells, as revealed by two-photon microscopy. Furthermore, the lung-specific depletion of DCs in mice that express the diphtheria toxin receptor under the control of the CD11c promoter interferes with BALT maintenance. Collectively, these data identify BALT as tertiary lymphoid structures supporting the efficient priming of T cell responses directed against unrelated airborne antigens while crucially requiring DCs for its sustained presence.

Show MeSH
Related in: MedlinePlus