Limits...
CpG-matured murine plasmacytoid dendritic cells are capable of in vivo priming of functional CD8 T cell responses to endogenous but not exogenous antigens.

Salio M, Palmowski MJ, Atzberger A, Hermans IF, Cerundolo V - J. Exp. Med. (2004)

Bottom Line: In vitro experiments have shown that upon maturation, human and murine PDCs develop into potent immunostimulatory cells; however, their ability to prime an immune response in vivo remains to be addressed.In contrast, immature PDCs are unable to prime antigen-specific CTLs.Our results underline the heterogeneity and plasticity of different antigen-presenting cells, and reveal an important role of mature PDCs in priming CD8 responses to endogenous antigens, in addition to their previously reported ability to modulate antiviral responses via type I IFN.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research Tumor Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headley Way, OX3 9DS Oxford, UK. mariolina.salio@imm.ox.ac.uk

ABSTRACT
Plasmacytoid dendritic cells (PDCs) are a unique leukocyte population capable of secreting high levels of type I interferon (IFN) in response to viruses and bacterial stimuli. In vitro experiments have shown that upon maturation, human and murine PDCs develop into potent immunostimulatory cells; however, their ability to prime an immune response in vivo remains to be addressed. We report that CpG-matured murine PDCs are capable of eliciting in naive mice antigen-specific CTLs against endogenous antigens as well as exogenous peptides, but not against an exogenous antigen. Type I IFN is not required for priming, as injection of CpG-matured PDCs into type I IFN receptor-deficient mice elicits functional CTL responses. Mature PDCs prime CTLs that secrete IFN-gamma and protect mice from a tumor challenge. In contrast, immature PDCs are unable to prime antigen-specific CTLs. However, mice injected with immature PDCs are fully responsive to secondary antigenic challenges, suggesting that PDCs have not induced long-lasting tolerance via anergic or regulatory T cells. Our results underline the heterogeneity and plasticity of different antigen-presenting cells, and reveal an important role of mature PDCs in priming CD8 responses to endogenous antigens, in addition to their previously reported ability to modulate antiviral responses via type I IFN.

Show MeSH

Related in: MedlinePlus

Type I IFN receptor–deficient CpG-matured male PDCs prime IFN-γ–secreting CTL. Type I IFN receptor–deficient mice (129A; n = 2) were injected i.v. with 0.6 × 105 CpG-matured MDC or PDCs (also generated from 129A mice). 2 wk after priming, mice were boosted with UV-inactivated vaccinia-UTY246–254 minigene. (A) CTL responses were assessed in the blood by FACS® analysis using UTY246–254-H-2-Db tetramers 9 d after priming (gray bars) or 8 d after boosting (black bars). Tetramer stainings of control mice, naive or primed by vaccinia-UTY246–254 minigene alone, are shown as white bars (the priming conditions are specified on the x axis). Mean proportions of tetramer+ cells as a percentage of CD8 cells (± SEM) for each group are shown. (B) IFN-γ ELISPOT was performed on blood PBLs to assess responsiveness to 10 μg/ml UTY246–254 peptide 9 d after priming. All animals showed comparable responses to PHA stimulation (not depicted).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2211835&req=5

fig8: Type I IFN receptor–deficient CpG-matured male PDCs prime IFN-γ–secreting CTL. Type I IFN receptor–deficient mice (129A; n = 2) were injected i.v. with 0.6 × 105 CpG-matured MDC or PDCs (also generated from 129A mice). 2 wk after priming, mice were boosted with UV-inactivated vaccinia-UTY246–254 minigene. (A) CTL responses were assessed in the blood by FACS® analysis using UTY246–254-H-2-Db tetramers 9 d after priming (gray bars) or 8 d after boosting (black bars). Tetramer stainings of control mice, naive or primed by vaccinia-UTY246–254 minigene alone, are shown as white bars (the priming conditions are specified on the x axis). Mean proportions of tetramer+ cells as a percentage of CD8 cells (± SEM) for each group are shown. (B) IFN-γ ELISPOT was performed on blood PBLs to assess responsiveness to 10 μg/ml UTY246–254 peptide 9 d after priming. All animals showed comparable responses to PHA stimulation (not depicted).

Mentions: As compared with 129 wild-type mice, 129A mice had normal numbers of PDCs ex vivo in the spleen and in vitro after culturing bone marrow cells in the presence of FLT3-L (unpublished data). In addition, 129A PDCs underwent maturation after CpG treatment, although to a lower extent than their wild-type counterpart (Fig. S3, available at http://www.jem.org/cgi/content/full/jem.20031059/DC1). Female 129A mice injected with male CpG-matured 129A PDCs developed antigen-specific CTLs, which could also be boosted by UV-inactivated vaccinia UTY246–254 minigene, as shown previously for C57BL/6 mice (Fig. 8 A). In addition, UTY246–254-specific CTLs primed by mature 129A PDCs secreted IFN-γ in response to the cognate peptide in an ex vivo ELISPOT assay (Fig. 8 B). These results suggest that in the absence of viral infection, type I IFN responsiveness is not essential for CTL priming by CpG-matured PDCs.


CpG-matured murine plasmacytoid dendritic cells are capable of in vivo priming of functional CD8 T cell responses to endogenous but not exogenous antigens.

Salio M, Palmowski MJ, Atzberger A, Hermans IF, Cerundolo V - J. Exp. Med. (2004)

Type I IFN receptor–deficient CpG-matured male PDCs prime IFN-γ–secreting CTL. Type I IFN receptor–deficient mice (129A; n = 2) were injected i.v. with 0.6 × 105 CpG-matured MDC or PDCs (also generated from 129A mice). 2 wk after priming, mice were boosted with UV-inactivated vaccinia-UTY246–254 minigene. (A) CTL responses were assessed in the blood by FACS® analysis using UTY246–254-H-2-Db tetramers 9 d after priming (gray bars) or 8 d after boosting (black bars). Tetramer stainings of control mice, naive or primed by vaccinia-UTY246–254 minigene alone, are shown as white bars (the priming conditions are specified on the x axis). Mean proportions of tetramer+ cells as a percentage of CD8 cells (± SEM) for each group are shown. (B) IFN-γ ELISPOT was performed on blood PBLs to assess responsiveness to 10 μg/ml UTY246–254 peptide 9 d after priming. All animals showed comparable responses to PHA stimulation (not depicted).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211835&req=5

fig8: Type I IFN receptor–deficient CpG-matured male PDCs prime IFN-γ–secreting CTL. Type I IFN receptor–deficient mice (129A; n = 2) were injected i.v. with 0.6 × 105 CpG-matured MDC or PDCs (also generated from 129A mice). 2 wk after priming, mice were boosted with UV-inactivated vaccinia-UTY246–254 minigene. (A) CTL responses were assessed in the blood by FACS® analysis using UTY246–254-H-2-Db tetramers 9 d after priming (gray bars) or 8 d after boosting (black bars). Tetramer stainings of control mice, naive or primed by vaccinia-UTY246–254 minigene alone, are shown as white bars (the priming conditions are specified on the x axis). Mean proportions of tetramer+ cells as a percentage of CD8 cells (± SEM) for each group are shown. (B) IFN-γ ELISPOT was performed on blood PBLs to assess responsiveness to 10 μg/ml UTY246–254 peptide 9 d after priming. All animals showed comparable responses to PHA stimulation (not depicted).
Mentions: As compared with 129 wild-type mice, 129A mice had normal numbers of PDCs ex vivo in the spleen and in vitro after culturing bone marrow cells in the presence of FLT3-L (unpublished data). In addition, 129A PDCs underwent maturation after CpG treatment, although to a lower extent than their wild-type counterpart (Fig. S3, available at http://www.jem.org/cgi/content/full/jem.20031059/DC1). Female 129A mice injected with male CpG-matured 129A PDCs developed antigen-specific CTLs, which could also be boosted by UV-inactivated vaccinia UTY246–254 minigene, as shown previously for C57BL/6 mice (Fig. 8 A). In addition, UTY246–254-specific CTLs primed by mature 129A PDCs secreted IFN-γ in response to the cognate peptide in an ex vivo ELISPOT assay (Fig. 8 B). These results suggest that in the absence of viral infection, type I IFN responsiveness is not essential for CTL priming by CpG-matured PDCs.

Bottom Line: In vitro experiments have shown that upon maturation, human and murine PDCs develop into potent immunostimulatory cells; however, their ability to prime an immune response in vivo remains to be addressed.In contrast, immature PDCs are unable to prime antigen-specific CTLs.Our results underline the heterogeneity and plasticity of different antigen-presenting cells, and reveal an important role of mature PDCs in priming CD8 responses to endogenous antigens, in addition to their previously reported ability to modulate antiviral responses via type I IFN.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research Tumor Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headley Way, OX3 9DS Oxford, UK. mariolina.salio@imm.ox.ac.uk

ABSTRACT
Plasmacytoid dendritic cells (PDCs) are a unique leukocyte population capable of secreting high levels of type I interferon (IFN) in response to viruses and bacterial stimuli. In vitro experiments have shown that upon maturation, human and murine PDCs develop into potent immunostimulatory cells; however, their ability to prime an immune response in vivo remains to be addressed. We report that CpG-matured murine PDCs are capable of eliciting in naive mice antigen-specific CTLs against endogenous antigens as well as exogenous peptides, but not against an exogenous antigen. Type I IFN is not required for priming, as injection of CpG-matured PDCs into type I IFN receptor-deficient mice elicits functional CTL responses. Mature PDCs prime CTLs that secrete IFN-gamma and protect mice from a tumor challenge. In contrast, immature PDCs are unable to prime antigen-specific CTLs. However, mice injected with immature PDCs are fully responsive to secondary antigenic challenges, suggesting that PDCs have not induced long-lasting tolerance via anergic or regulatory T cells. Our results underline the heterogeneity and plasticity of different antigen-presenting cells, and reveal an important role of mature PDCs in priming CD8 responses to endogenous antigens, in addition to their previously reported ability to modulate antiviral responses via type I IFN.

Show MeSH
Related in: MedlinePlus