title: The C-terminal extension of Leishmania pifanoi amastigote-specific cysteine proteinase Lpcys2: a putative function in macrophage infection.
abstract: Cysteine proteinases have been implicated in many aspects of protozoan parasite pathogenesis. These hydrolases are normally found as zymogens, and some classes in trypanosomatids possess a long C-terminal extension (CTE), for which no function has been assigned. In this paper we hypothesize that the CTE domain of Lpcys2, the abundant lysosomal cysteine proteinase of Leishmania pifanoi amastigotes, is involved in host cell infection. Confirming previous reports that this peptide is highly immunogenic in Trypanosoma cruzi, we detected antibodies against CTE in sera of leishmaniasis patients. We produced a polyclonal antibody specific to Lpcys2 CTE and determined that this antibody was capable of recognizing both L. pifanoi and Leishmania amazonensis cysteine proteinases. Using this antibody, we detected a predominant localization of Lpcys2 CTE in the lysosome and flagellar pocket of cultured axenic amastigotes of both parasite species; however, its location was shifted towards the surface of the parasites during macrophage infection. We examined the role of Lpcys2 CTE in macrophage infection and found a significant reduction in the percentage of infected cells when macrophages were infected with L. pifanoi and L. amazonensis in the presence of anti-CTE antibody. This study suggests a role for leishmanial cysteine proteinases CTE at early stages of infection.
authors.affiliation: Laboratório de Biologia Molecular de Tripanosomatídeos e Flebotomíneos, Instituto Oswaldo Cruz, Fiocruz, Av. Brasil 4365, Manguinhos, Rio de Janeiro, RJ, Brazil
authors.forename: Marcel
authors.initials: M
authors.lastname: Marín-Villa
authors.forename: Diego A
authors.initials: DA
authors.lastname: Vargas-Inchaustegui
authors.forename: Suzana P
authors.initials: SP
authors.lastname: Chaves
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Tempone
authors.forename: Juliana M F
authors.initials: JM
authors.lastname: Dutra
authors.forename: Maurilio J
authors.initials: MJ
authors.lastname: Soares
authors.forename: Tania
authors.initials: T
authors.lastname: Ueda-Nakamura
authors.forename: Sergio C F
authors.initials: SC
authors.lastname: Mendonça
authors.forename: Bartira
authors.initials: B
authors.lastname: Rossi-Bergmann
authors.forename: Lynn
authors.initials: L
authors.lastname: Soong
authors.forename: Yara M
authors.initials: YM
authors.lastname: Traub-Csekö
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D006790:Host-Parasite Interactions; D006801:Humans; D007891:Leishmania / Q000145:classification / Q000201:enzymology* / Q000472:pathogenicity* / Q000648:ultrastructure; D007896:Leishmaniasis / Q000276:immunology / Q000469:parasitology*; D008247:Lysosomes / Q000201:enzymology / Q000648:ultrastructure; D017737:Macrophages, Peritoneal / Q000469:parasitology*; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission
chemical_list: D000913:Antibodies, Protozoan; D003546:Cysteine Endopeptidases