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Hepatocyte permissiveness to Plasmodium infection is conveyed by a short and structurally conserved region of the CD81 large extracellular domain.

Yalaoui S, Zougbédé S, Charrin S, Silvie O, Arduise C, Farhati K, Boucheix C, Mazier D, Rubinstein E, Froissard P - PLoS Pathog. (2008)

Bottom Line: Still, the molecular mechanisms underlying sporozoite invasion are largely unknown.By site-directed mutagenesis, we have demonstrated the key role of a solvent-exposed region around residue D137 within this domain.This study has uncovered a new functionally important region of CD81, independent of HCV E2 envelope protein binding domain, and further suggests that CD81 may not interact directly with a parasite ligand during Plasmodium infection, but instead may regulate the function of a yet unknown partner protein.

View Article: PubMed Central - PubMed

Affiliation: Université Pierre et Marie Curie-Paris6, UMR S511, Paris, France.

ABSTRACT
Invasion of hepatocytes by Plasmodium sporozoites is a prerequisite for establishment of a malaria infection, and thus represents an attractive target for anti-malarial interventions. Still, the molecular mechanisms underlying sporozoite invasion are largely unknown. We have previously reported that the tetraspanin CD81, a known receptor for the hepatitis C virus (HCV), is required on hepatocytes for infection by sporozoites of several Plasmodium species. Here we have characterized CD81 molecular determinants required for infection of hepatocytic cells by P. yoelii sporozoites. Using CD9/CD81 chimeras, we have identified in CD81 a 21 amino acid stretch located in a domain structurally conserved in the large extracellular loop of tetraspanins, which is sufficient in an otherwise CD9 background to confer susceptibility to P. yoelii infection. By site-directed mutagenesis, we have demonstrated the key role of a solvent-exposed region around residue D137 within this domain. A mAb that requires this region for optimal binding did not block infection, in contrast to other CD81 mAbs. This study has uncovered a new functionally important region of CD81, independent of HCV E2 envelope protein binding domain, and further suggests that CD81 may not interact directly with a parasite ligand during Plasmodium infection, but instead may regulate the function of a yet unknown partner protein.

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The same determinants are involved in a murine model.Hepa1-6 cells were transfected with the indicated plasmids 24 hours before infection with P. yoelii sporozoites in the presence of the anti-mouse CD81 mAb MT81 as indicated. The number of EEF-infected cells (mean±s.d.) was determined as described in the Materials and Methods section. **, p<0.01 as compared to MT81-treated, mock-transfected cells.
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ppat-1000010-g005: The same determinants are involved in a murine model.Hepa1-6 cells were transfected with the indicated plasmids 24 hours before infection with P. yoelii sporozoites in the presence of the anti-mouse CD81 mAb MT81 as indicated. The number of EEF-infected cells (mean±s.d.) was determined as described in the Materials and Methods section. **, p<0.01 as compared to MT81-treated, mock-transfected cells.

Mentions: To check that the above results were not HepG2-A16 cell specific, we tested whether CD81 structural requirements were the same in the murine cell line Hepa1-6. This cell line expresses mCD81 and is permissive to P. yoelii infection. Treatment with an anti mouse CD81 mAb (MT81) prevents infection by this parasite [13] (Fig. 5). When cells are transfected with hCD81, they remain susceptible to infection despite MT81 treatment because the anti-mouse CD81 mAb does not recognize hCD81 (which can functionally replace mCD81 in this model [13]) (Fig. 5). These cells therefore represent an alternative model to study the molecular determinants of CD81 that play a role in the infection of hepatocytic cells by P. yoelii sporozoites.


Hepatocyte permissiveness to Plasmodium infection is conveyed by a short and structurally conserved region of the CD81 large extracellular domain.

Yalaoui S, Zougbédé S, Charrin S, Silvie O, Arduise C, Farhati K, Boucheix C, Mazier D, Rubinstein E, Froissard P - PLoS Pathog. (2008)

The same determinants are involved in a murine model.Hepa1-6 cells were transfected with the indicated plasmids 24 hours before infection with P. yoelii sporozoites in the presence of the anti-mouse CD81 mAb MT81 as indicated. The number of EEF-infected cells (mean±s.d.) was determined as described in the Materials and Methods section. **, p<0.01 as compared to MT81-treated, mock-transfected cells.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2279262&req=5

ppat-1000010-g005: The same determinants are involved in a murine model.Hepa1-6 cells were transfected with the indicated plasmids 24 hours before infection with P. yoelii sporozoites in the presence of the anti-mouse CD81 mAb MT81 as indicated. The number of EEF-infected cells (mean±s.d.) was determined as described in the Materials and Methods section. **, p<0.01 as compared to MT81-treated, mock-transfected cells.
Mentions: To check that the above results were not HepG2-A16 cell specific, we tested whether CD81 structural requirements were the same in the murine cell line Hepa1-6. This cell line expresses mCD81 and is permissive to P. yoelii infection. Treatment with an anti mouse CD81 mAb (MT81) prevents infection by this parasite [13] (Fig. 5). When cells are transfected with hCD81, they remain susceptible to infection despite MT81 treatment because the anti-mouse CD81 mAb does not recognize hCD81 (which can functionally replace mCD81 in this model [13]) (Fig. 5). These cells therefore represent an alternative model to study the molecular determinants of CD81 that play a role in the infection of hepatocytic cells by P. yoelii sporozoites.

Bottom Line: Still, the molecular mechanisms underlying sporozoite invasion are largely unknown.By site-directed mutagenesis, we have demonstrated the key role of a solvent-exposed region around residue D137 within this domain.This study has uncovered a new functionally important region of CD81, independent of HCV E2 envelope protein binding domain, and further suggests that CD81 may not interact directly with a parasite ligand during Plasmodium infection, but instead may regulate the function of a yet unknown partner protein.

View Article: PubMed Central - PubMed

Affiliation: Université Pierre et Marie Curie-Paris6, UMR S511, Paris, France.

ABSTRACT
Invasion of hepatocytes by Plasmodium sporozoites is a prerequisite for establishment of a malaria infection, and thus represents an attractive target for anti-malarial interventions. Still, the molecular mechanisms underlying sporozoite invasion are largely unknown. We have previously reported that the tetraspanin CD81, a known receptor for the hepatitis C virus (HCV), is required on hepatocytes for infection by sporozoites of several Plasmodium species. Here we have characterized CD81 molecular determinants required for infection of hepatocytic cells by P. yoelii sporozoites. Using CD9/CD81 chimeras, we have identified in CD81 a 21 amino acid stretch located in a domain structurally conserved in the large extracellular loop of tetraspanins, which is sufficient in an otherwise CD9 background to confer susceptibility to P. yoelii infection. By site-directed mutagenesis, we have demonstrated the key role of a solvent-exposed region around residue D137 within this domain. A mAb that requires this region for optimal binding did not block infection, in contrast to other CD81 mAbs. This study has uncovered a new functionally important region of CD81, independent of HCV E2 envelope protein binding domain, and further suggests that CD81 may not interact directly with a parasite ligand during Plasmodium infection, but instead may regulate the function of a yet unknown partner protein.

Show MeSH
Related in: MedlinePlus