title: Targeted gene deletion in Leishmania major identifies leishmanolysin (GP63) as a virulence factor.
abstract: Leishmanolysin, the Leishmania surface metalloproteinase of 63 kDa (GP63) has been described as a parasite virulence factor and is involved in the direct interaction of promastigotes and host macrophage receptors and interaction with the complement cascade. To study the role of leishmanolysin in the pathogenesis and virulence of Leishmania major, targeted gene replacement was used to delete the entire 20 kb region containing all seven leishmanolysin genes (gp63 genes 1-7). The resulting L. major leishmanolysin deficient mutants showed normal development inside the sand fly vector, however, promastigotes recovered from sand flies or from culture showed an increase in sensitivity to complement-mediated lysis and a delay in lesion formation in BALB/c animals. The phenotypic differences could be significantly improved by expression of a cloned leishmanolysin gene. These results demonstrate that leishmanolysin is a vital virulence factor in Leishmania pathogenesis.
authors.affiliation: Department of Medical Genetics, Jack Bell Research Centre, University of British Columbia and Immunity and Infection Research Centre, Vancouver Hospital, 2660 Oak Street, BC, V6H 3Z6, Vancouver, Canada. robm@interchange.ubc.ca
authors.forename: Phalgun B
authors.initials: PB
authors.lastname: Joshi
authors.forename: Ben L
authors.initials: BL
authors.lastname: Kelly
authors.forename: Shaden
authors.initials: S
authors.lastname: Kamhawi
authors.forename: David L
authors.initials: DL
authors.lastname: Sacks
authors.forename: W Robert
authors.initials: WR
authors.lastname: McMaster
mesh_terms: D000818:Animals; D003165:Complement System Proteins / Q000276:immunology; D017353:Gene Deletion; D018390:Gene Targeting; D018320:Leishmania major / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D016773:Leishmaniasis, Cutaneous / Q000469:parasitology / Q000503:physiopathology*; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010691:Phlebotomus / Q000469:parasitology; D014774:Virulence
chemical_list: D003165:Complement System Proteins; D008666:Metalloendopeptidases; C055146:glycoprotein gp63, Leishmania