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Prominent and persistent extraneural infection in human PrP transgenic mice infected with variant CJD.

Béringue V, Le Dur A, Tixador P, Reine F, Lepourry L, Perret-Liaudet A, Haïk S, Vilotte JL, Fontés M, Laude H - PLoS ONE (2008)

Bottom Line: We showed that i) the main features of vCJD infection in humans, including a prominent involvement of the lymphoid tissues compared to that in sCJD infection were faithfully reproduced in such mice; ii) transmission of vCJD agent by intracerebral route could lead to the propagation of either vCJD or sCJD-like prion in the brain, whereas vCJD prion was invariably propagated in the spleen, iii) after peripheral exposure, inefficient neuroinvasion was observed, resulting in an asymptomatic infection with life-long persistence of vCJD prion in the spleen at stable and elevated levels.Our findings emphasize the possibility that human-to-human transmission of vCJD might produce alternative neuropathological phenotypes and that lymphoid tissue examination of CJD cases classified as sporadic might reveal an infection by vCJD-type prions.They also provide evidence for the strong propensity of this agent to establish long-lasting, subclinical vCJD infection of lymphoreticular tissues, thus amplifying the risk for iatrogenic transmission.

View Article: PubMed Central - PubMed

Affiliation: Institut Scientifique de Recherche Agronomique (INRA), UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France. vincent.beringue@jouy.inra.fr

ABSTRACT

Background: The evolution of the variant Creutzfeldt-Jakob disease (vCJD) epidemic is hazardous to predict due to uncertainty in ascertaining the prevalence of infection and because the disease might remain asymptomatic or produce an alternate, sporadic-like phenotype.

Methodology/principal findings: Transgenic mice were produced that overexpress human prion protein with methionine at codon 129, the only allele found so far in vCJD-affected patients. These mice were infected with prions derived from variant and sporadic CJD (sCJD) cases by intracerebral or intraperitoneal route, and transmission efficiency and strain phenotype were analyzed in brain and spleen. We showed that i) the main features of vCJD infection in humans, including a prominent involvement of the lymphoid tissues compared to that in sCJD infection were faithfully reproduced in such mice; ii) transmission of vCJD agent by intracerebral route could lead to the propagation of either vCJD or sCJD-like prion in the brain, whereas vCJD prion was invariably propagated in the spleen, iii) after peripheral exposure, inefficient neuroinvasion was observed, resulting in an asymptomatic infection with life-long persistence of vCJD prion in the spleen at stable and elevated levels.

Conclusion/significance: Our findings emphasize the possibility that human-to-human transmission of vCJD might produce alternative neuropathological phenotypes and that lymphoid tissue examination of CJD cases classified as sporadic might reveal an infection by vCJD-type prions. They also provide evidence for the strong propensity of this agent to establish long-lasting, subclinical vCJD infection of lymphoreticular tissues, thus amplifying the risk for iatrogenic transmission.

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PrPres accumulation in tg650 mice intraperitoneally infected with vCJD.(A) PrPres electrophoretic pattern in spleen (sp, circle) and brain (br, square) of mice euthanised healthy in triplicates up to 550 days post-infection (broken line) or at end of life time. vCJD- and sCJD-associated PrPres pattern are represented as brown and grey color, respectively. Empty symbols indicate PrPres negative tissue. Mock-infected mice (mock) were intraperitoneally inoculated with human brain without any TSE. (B) Quantification of PrPres levels in the spleens on secondary transmission of vCJD (late brain). Spleen tissue was collected from healthy mice euthanised in triplicates at regular time points or individually at the end of life (see above). PrPres was extracted, detected by western blot and quantified with a bio-imaging system for chemiluminescence applications (see Methods). Results are expressed in arbitrary units (logarithmic scale). The standard deviations for triplicates without error bars were too small to be represented. (C) Electrophoretic pattern of PrPres in brain (Br) spleen (Sp) at various times after inoculation of the indicated brain materials.
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pone-0001419-g004: PrPres accumulation in tg650 mice intraperitoneally infected with vCJD.(A) PrPres electrophoretic pattern in spleen (sp, circle) and brain (br, square) of mice euthanised healthy in triplicates up to 550 days post-infection (broken line) or at end of life time. vCJD- and sCJD-associated PrPres pattern are represented as brown and grey color, respectively. Empty symbols indicate PrPres negative tissue. Mock-infected mice (mock) were intraperitoneally inoculated with human brain without any TSE. (B) Quantification of PrPres levels in the spleens on secondary transmission of vCJD (late brain). Spleen tissue was collected from healthy mice euthanised in triplicates at regular time points or individually at the end of life (see above). PrPres was extracted, detected by western blot and quantified with a bio-imaging system for chemiluminescence applications (see Methods). Results are expressed in arbitrary units (logarithmic scale). The standard deviations for triplicates without error bars were too small to be represented. (C) Electrophoretic pattern of PrPres in brain (Br) spleen (Sp) at various times after inoculation of the indicated brain materials.

Mentions: We next sought to investigate the pathogenesis of the infection following inoculation of tg650 mice by the peripheral route. Mice were inoculated intraperitoneally with brain material from vCJD- or sCJD-infected humans and from vCJD no. 4 mouse passages. Animals were euthanised at various times post-infection (pi), from which the brain and spleen were collected for PrPres analysis by immunoblotting. Importantly, mice inoculated with vCJD prions peripherally appeared not to develop clinical disease, unlike their intracranially inoculated counterparts. Yet PrPvCJD was readily detected in the spleen, and this from 100 days pi onward (Figure 4A). Moreover, quantitative analysis revealed that the PrPres levels did not greatly vary during the life of the mouse (Figure 4B–C), except perhaps a slight decrease at late stage of infection, possibly due to age-related impairment of the follicular dendritic cells (for review [21]) that support PrPres accumulation in spleen [22]. In the brain, PrPres was detected only lately and in a proportion of the mice; its banding pattern was of vCJD type in late mice and of sCJD type in early mice subpassage, like following intracerebral inoculation (Figure 4A, C). In contrast, even after intraperitoneal challenge, we failed to detect PrPres accumulation in the spleens of sCJD-infected mice (Figure 4C).


Prominent and persistent extraneural infection in human PrP transgenic mice infected with variant CJD.

Béringue V, Le Dur A, Tixador P, Reine F, Lepourry L, Perret-Liaudet A, Haïk S, Vilotte JL, Fontés M, Laude H - PLoS ONE (2008)

PrPres accumulation in tg650 mice intraperitoneally infected with vCJD.(A) PrPres electrophoretic pattern in spleen (sp, circle) and brain (br, square) of mice euthanised healthy in triplicates up to 550 days post-infection (broken line) or at end of life time. vCJD- and sCJD-associated PrPres pattern are represented as brown and grey color, respectively. Empty symbols indicate PrPres negative tissue. Mock-infected mice (mock) were intraperitoneally inoculated with human brain without any TSE. (B) Quantification of PrPres levels in the spleens on secondary transmission of vCJD (late brain). Spleen tissue was collected from healthy mice euthanised in triplicates at regular time points or individually at the end of life (see above). PrPres was extracted, detected by western blot and quantified with a bio-imaging system for chemiluminescence applications (see Methods). Results are expressed in arbitrary units (logarithmic scale). The standard deviations for triplicates without error bars were too small to be represented. (C) Electrophoretic pattern of PrPres in brain (Br) spleen (Sp) at various times after inoculation of the indicated brain materials.
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Related In: Results  -  Collection

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pone-0001419-g004: PrPres accumulation in tg650 mice intraperitoneally infected with vCJD.(A) PrPres electrophoretic pattern in spleen (sp, circle) and brain (br, square) of mice euthanised healthy in triplicates up to 550 days post-infection (broken line) or at end of life time. vCJD- and sCJD-associated PrPres pattern are represented as brown and grey color, respectively. Empty symbols indicate PrPres negative tissue. Mock-infected mice (mock) were intraperitoneally inoculated with human brain without any TSE. (B) Quantification of PrPres levels in the spleens on secondary transmission of vCJD (late brain). Spleen tissue was collected from healthy mice euthanised in triplicates at regular time points or individually at the end of life (see above). PrPres was extracted, detected by western blot and quantified with a bio-imaging system for chemiluminescence applications (see Methods). Results are expressed in arbitrary units (logarithmic scale). The standard deviations for triplicates without error bars were too small to be represented. (C) Electrophoretic pattern of PrPres in brain (Br) spleen (Sp) at various times after inoculation of the indicated brain materials.
Mentions: We next sought to investigate the pathogenesis of the infection following inoculation of tg650 mice by the peripheral route. Mice were inoculated intraperitoneally with brain material from vCJD- or sCJD-infected humans and from vCJD no. 4 mouse passages. Animals were euthanised at various times post-infection (pi), from which the brain and spleen were collected for PrPres analysis by immunoblotting. Importantly, mice inoculated with vCJD prions peripherally appeared not to develop clinical disease, unlike their intracranially inoculated counterparts. Yet PrPvCJD was readily detected in the spleen, and this from 100 days pi onward (Figure 4A). Moreover, quantitative analysis revealed that the PrPres levels did not greatly vary during the life of the mouse (Figure 4B–C), except perhaps a slight decrease at late stage of infection, possibly due to age-related impairment of the follicular dendritic cells (for review [21]) that support PrPres accumulation in spleen [22]. In the brain, PrPres was detected only lately and in a proportion of the mice; its banding pattern was of vCJD type in late mice and of sCJD type in early mice subpassage, like following intracerebral inoculation (Figure 4A, C). In contrast, even after intraperitoneal challenge, we failed to detect PrPres accumulation in the spleens of sCJD-infected mice (Figure 4C).

Bottom Line: We showed that i) the main features of vCJD infection in humans, including a prominent involvement of the lymphoid tissues compared to that in sCJD infection were faithfully reproduced in such mice; ii) transmission of vCJD agent by intracerebral route could lead to the propagation of either vCJD or sCJD-like prion in the brain, whereas vCJD prion was invariably propagated in the spleen, iii) after peripheral exposure, inefficient neuroinvasion was observed, resulting in an asymptomatic infection with life-long persistence of vCJD prion in the spleen at stable and elevated levels.Our findings emphasize the possibility that human-to-human transmission of vCJD might produce alternative neuropathological phenotypes and that lymphoid tissue examination of CJD cases classified as sporadic might reveal an infection by vCJD-type prions.They also provide evidence for the strong propensity of this agent to establish long-lasting, subclinical vCJD infection of lymphoreticular tissues, thus amplifying the risk for iatrogenic transmission.

View Article: PubMed Central - PubMed

Affiliation: Institut Scientifique de Recherche Agronomique (INRA), UR892, Virologie Immunologie Moléculaires, Jouy-en-Josas, France. vincent.beringue@jouy.inra.fr

ABSTRACT

Background: The evolution of the variant Creutzfeldt-Jakob disease (vCJD) epidemic is hazardous to predict due to uncertainty in ascertaining the prevalence of infection and because the disease might remain asymptomatic or produce an alternate, sporadic-like phenotype.

Methodology/principal findings: Transgenic mice were produced that overexpress human prion protein with methionine at codon 129, the only allele found so far in vCJD-affected patients. These mice were infected with prions derived from variant and sporadic CJD (sCJD) cases by intracerebral or intraperitoneal route, and transmission efficiency and strain phenotype were analyzed in brain and spleen. We showed that i) the main features of vCJD infection in humans, including a prominent involvement of the lymphoid tissues compared to that in sCJD infection were faithfully reproduced in such mice; ii) transmission of vCJD agent by intracerebral route could lead to the propagation of either vCJD or sCJD-like prion in the brain, whereas vCJD prion was invariably propagated in the spleen, iii) after peripheral exposure, inefficient neuroinvasion was observed, resulting in an asymptomatic infection with life-long persistence of vCJD prion in the spleen at stable and elevated levels.

Conclusion/significance: Our findings emphasize the possibility that human-to-human transmission of vCJD might produce alternative neuropathological phenotypes and that lymphoid tissue examination of CJD cases classified as sporadic might reveal an infection by vCJD-type prions. They also provide evidence for the strong propensity of this agent to establish long-lasting, subclinical vCJD infection of lymphoreticular tissues, thus amplifying the risk for iatrogenic transmission.

Show MeSH
Related in: MedlinePlus