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Dendritic cell-mediated-immunization with xenogenic PrP and adenoviral vectors breaks tolerance and prolongs mice survival against experimental scrapie.

Rosset MB, Sacquin A, Lecollinet S, Chaigneau T, Adam M, Crespeau F, Eloit M - PLoS ONE (2009)

Bottom Line: Other effectors with potential to eliminate PrPSc-producing cells are cytotoxic T cells directed against PrP-derived peptides but their ability to protect or to induce deleterious autoimmune reactions is not known.Frequencies of PrP-specific IFNgamma-secreting T cells were low and in vivo lytic activity only targeted cells strongly expressing hPrP.The efficacy appeared to be associated with antibody but not with cytotoxic cell-mediated PrP-specific responses.

View Article: PubMed Central - PubMed

Affiliation: INSERM UMR 938, Paris, France. martine.rosset@inserm.fr

ABSTRACT
In prion diseases, PrP(c), a widely expressed protein, is transformed into a pathogenic form called PrP(Sc), which is in itself infectious. Antibodies directed against PrP(c) have been shown to inhibit PrP(c) to PrP(Sc) conversion in vitro and protect in vivo from disease. Other effectors with potential to eliminate PrPSc-producing cells are cytotoxic T cells directed against PrP-derived peptides but their ability to protect or to induce deleterious autoimmune reactions is not known. The natural tolerance to PrP(c) makes difficult to raise efficient adaptive responses. To break tolerance, adenovirus (Ad) encoding human PrP (hPrP) or control Ad were administered to wild-type mice by direct injection or by transfer of Ad-transduced dendritic cells (DCs). Control Ad-transduced DCs from Tg650 mice overexpressing hPrP were also used for immunization. DC-mediated but not direct administration of AdhPrP elicited antibodies that bound to murine native PrP(c). Frequencies of PrP-specific IFNgamma-secreting T cells were low and in vivo lytic activity only targeted cells strongly expressing hPrP. Immunohistochemical analysis revealed that CD3(+) T cell infiltration was similar in the brain of vaccinated and unvaccinated 139A-infected mice suggesting the absence of autoimmune reactions. Early splenic PrP(Sc) replication was strongly inhibited ten weeks post infection and mean survival time prolonged from 209 days in untreated 139A-infected mice to 246 days in mice vaccinated with DCs expressing the hPrP. The efficacy appeared to be associated with antibody but not with cytotoxic cell-mediated PrP-specific responses.

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Expression of MHC class II, B7.2 and hPrP analysed by fow cytometry.BM-derived CD11c DCs prepared from C57BL/6 (left panel) and Tg650 (right panel) mice before (- - -) and after LPS maturation ( ) and AdTA (. _ . _) or AdhPrP (.....) transfection. Cell surface expression of IAd (a), CD86 (b) and hPrP (c) molecules. Staining controls (PE-conjugated anti-mouse IgG2a) are depicted in grey.
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pone-0004917-g004: Expression of MHC class II, B7.2 and hPrP analysed by fow cytometry.BM-derived CD11c DCs prepared from C57BL/6 (left panel) and Tg650 (right panel) mice before (- - -) and after LPS maturation ( ) and AdTA (. _ . _) or AdhPrP (.....) transfection. Cell surface expression of IAd (a), CD86 (b) and hPrP (c) molecules. Staining controls (PE-conjugated anti-mouse IgG2a) are depicted in grey.

Mentions: Immunization protocols can be based on Ad-transduced DCs that are potent stimulators of CTL responses [35]–[36] and of T-dependent antibody production [37]–[38]. In this assay, DCs from C57BL/6 and Tg650 (overexpressing hPrP) were prepared from bone marrow and maturated in the presence of GM-CSF and LPS. DCs from Tg650 mice were transduced with AdTA (DCTg650AdTA) and DCs from B6 mice with AdhPrP (DCB6AdhPrP) or AdTA alone (DCB6AdTA). Up regulation of class II (IAb) molecules was observed in CD11c+ DCs from B6 and Tg650 mice after maturation with LPS and was further amplified following transduction with AdTA or AdhPrP (Fig. 4a). Expression of B7.2 costimulatory molecule, detected with an anti-CD86 mAb, increased after LPS-induced maturation, and furthermore following transduction of DCs with AdhPrP (Fig. 4b). Transduction of DCs from B6 mice with AdhPrP but not AdTA induced a high expression of hPrP evidenced by 4F2 mAb staining in 30% of the CD11c+ DCs, while transduced and non- transduced CD11c+DCs from Tg650 mice expressed as expected a high level of hPrP in 100% of cells (Fig. 4c).


Dendritic cell-mediated-immunization with xenogenic PrP and adenoviral vectors breaks tolerance and prolongs mice survival against experimental scrapie.

Rosset MB, Sacquin A, Lecollinet S, Chaigneau T, Adam M, Crespeau F, Eloit M - PLoS ONE (2009)

Expression of MHC class II, B7.2 and hPrP analysed by fow cytometry.BM-derived CD11c DCs prepared from C57BL/6 (left panel) and Tg650 (right panel) mice before (- - -) and after LPS maturation ( ) and AdTA (. _ . _) or AdhPrP (.....) transfection. Cell surface expression of IAd (a), CD86 (b) and hPrP (c) molecules. Staining controls (PE-conjugated anti-mouse IgG2a) are depicted in grey.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654673&req=5

pone-0004917-g004: Expression of MHC class II, B7.2 and hPrP analysed by fow cytometry.BM-derived CD11c DCs prepared from C57BL/6 (left panel) and Tg650 (right panel) mice before (- - -) and after LPS maturation ( ) and AdTA (. _ . _) or AdhPrP (.....) transfection. Cell surface expression of IAd (a), CD86 (b) and hPrP (c) molecules. Staining controls (PE-conjugated anti-mouse IgG2a) are depicted in grey.
Mentions: Immunization protocols can be based on Ad-transduced DCs that are potent stimulators of CTL responses [35]–[36] and of T-dependent antibody production [37]–[38]. In this assay, DCs from C57BL/6 and Tg650 (overexpressing hPrP) were prepared from bone marrow and maturated in the presence of GM-CSF and LPS. DCs from Tg650 mice were transduced with AdTA (DCTg650AdTA) and DCs from B6 mice with AdhPrP (DCB6AdhPrP) or AdTA alone (DCB6AdTA). Up regulation of class II (IAb) molecules was observed in CD11c+ DCs from B6 and Tg650 mice after maturation with LPS and was further amplified following transduction with AdTA or AdhPrP (Fig. 4a). Expression of B7.2 costimulatory molecule, detected with an anti-CD86 mAb, increased after LPS-induced maturation, and furthermore following transduction of DCs with AdhPrP (Fig. 4b). Transduction of DCs from B6 mice with AdhPrP but not AdTA induced a high expression of hPrP evidenced by 4F2 mAb staining in 30% of the CD11c+ DCs, while transduced and non- transduced CD11c+DCs from Tg650 mice expressed as expected a high level of hPrP in 100% of cells (Fig. 4c).

Bottom Line: Other effectors with potential to eliminate PrPSc-producing cells are cytotoxic T cells directed against PrP-derived peptides but their ability to protect or to induce deleterious autoimmune reactions is not known.Frequencies of PrP-specific IFNgamma-secreting T cells were low and in vivo lytic activity only targeted cells strongly expressing hPrP.The efficacy appeared to be associated with antibody but not with cytotoxic cell-mediated PrP-specific responses.

View Article: PubMed Central - PubMed

Affiliation: INSERM UMR 938, Paris, France. martine.rosset@inserm.fr

ABSTRACT
In prion diseases, PrP(c), a widely expressed protein, is transformed into a pathogenic form called PrP(Sc), which is in itself infectious. Antibodies directed against PrP(c) have been shown to inhibit PrP(c) to PrP(Sc) conversion in vitro and protect in vivo from disease. Other effectors with potential to eliminate PrPSc-producing cells are cytotoxic T cells directed against PrP-derived peptides but their ability to protect or to induce deleterious autoimmune reactions is not known. The natural tolerance to PrP(c) makes difficult to raise efficient adaptive responses. To break tolerance, adenovirus (Ad) encoding human PrP (hPrP) or control Ad were administered to wild-type mice by direct injection or by transfer of Ad-transduced dendritic cells (DCs). Control Ad-transduced DCs from Tg650 mice overexpressing hPrP were also used for immunization. DC-mediated but not direct administration of AdhPrP elicited antibodies that bound to murine native PrP(c). Frequencies of PrP-specific IFNgamma-secreting T cells were low and in vivo lytic activity only targeted cells strongly expressing hPrP. Immunohistochemical analysis revealed that CD3(+) T cell infiltration was similar in the brain of vaccinated and unvaccinated 139A-infected mice suggesting the absence of autoimmune reactions. Early splenic PrP(Sc) replication was strongly inhibited ten weeks post infection and mean survival time prolonged from 209 days in untreated 139A-infected mice to 246 days in mice vaccinated with DCs expressing the hPrP. The efficacy appeared to be associated with antibody but not with cytotoxic cell-mediated PrP-specific responses.

Show MeSH
Related in: MedlinePlus