title: Recognition of Human Erythrocyte Receptors by the Tryptophan-Rich Antigens of Monkey Malaria Parasite Plasmodium knowlesi.
abstract: BACKGROUND
  The monkey malaria parasite Plasmodium knowlesi also infect humans. There is a lack of information on the molecular mechanisms that take place between this simian parasite and its heterologous human host erythrocytes leading to this zoonotic disease. Therefore, we investigated here the binding ability of P. knowlesi tryptophan-rich antigens (PkTRAgs) to the human erythrocytes and sharing of the erythrocyte receptors between them as well as with other commonly occurring human malaria parasites.
  
  
  METHODS
  Six PkTRAgs were cloned and expressed in E.coli as well as in mammalian CHO-K1 cell to determine their human erythrocyte binding activity by cell-ELISA, and in-vitro rosetting assay, respectively.
  
  
  RESULTS
  Three of six PkTRAgs (PkTRAg38.3, PkTRAg40.1, and PkTRAg67.1) showed binding to human erythrocytes. Two of them (PkTRAg40.1 and PkTRAg38.3) showed cross-competition with each other as well as with the previously described P.vivax tryptophan-rich antigens (PvTRAgs) for human erythrocyte receptors. However, the third protein (PkTRAg67.1) utilized the additional but different human erythrocyte receptor(s) as it did not cross-compete for erythrocyte binding with either of these two PkTRAgs as well as with any of the PvTRAgs. These three PkTRAgs also inhibited the P.falciparum parasite growth in in-vitro culture, further indicating the sharing of human erythrocyte receptors by these parasite species and the biological significance of this receptor-ligand interaction between heterologous host and simian parasite.
  
  
  CONCLUSIONS
  Recognition and sharing of human erythrocyte receptor(s) by PkTRAgs with human parasite ligands could be part of the strategy adopted by the monkey malaria parasite to establish inside the heterologous human host.
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Kriti
authors.initials: K
authors.lastname: Tyagi
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Deepali
authors.initials: D
authors.lastname: Gupta
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Ekta
authors.initials: E
authors.lastname: Saini
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Shilpa
authors.initials: S
authors.lastname: Choudhary
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Jamwal
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Mohd Shoeb
authors.initials: MS
authors.lastname: Alam
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zeeshan
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Rupesh K
authors.initials: RK
authors.lastname: Tyagi
authors.affiliation: Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Yagya D
authors.initials: YD
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004912:Erythrocytes / Q000276:immunology* / Q000378:metabolism; D000882:Haplorhini; D006801:Humans; D008288:Malaria / Q000276:immunology / Q000469:parasitology; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016790:Plasmodium knowlesi / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D011956:Receptors, Cell Surface / Q000276:immunology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014364:Tryptophan / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
chemical_list: D000953:Antigens, Protozoan; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D014364:Tryptophan