title: Fasciola gigantica cathepsin L proteinase-based synthetic peptide for immunodiagnosis and prevention of sheep fasciolosis.
abstract: Sheep fasciolosis is a devastating burden for the livestock industry. We herein report on immunodiagnosis of fasciolosis, and significant protection of sheep against challenge infection with Fasciola gigantica following immunization with a peptide based on the H-Asp(110)-Lys-Ile-Asp-Trp-Arg-Glu-Ser-Gly-Tyr-Val-Thr-Glu-Val(123)-OH (Fas14p) sequence of F. gigantica cathepsin L-cysteine proteinase. This sequence was synthesized in three different forms: as N(alpha) acetylated (Ac-Asp(110)-Lys-Ile-Asp-Trp-Arg-Glu-Ser-Gly-Tyr-Val-Thr-Glu-Val(123)-OH, FasAc14p), bearing at the amino-terminus an N(alpha) acetylated cystein (Ac-Cys-Asp(110)-Lys-Ile-Asp-Trp-Arg-Glu-Ser-Gly-Tyr-Val-Thr-Glu-Val(123)-OH, FasAcCys14p), and conjugated to sequential oligopeptide carrier Ac-[Lys-Aib-Gly](4)-OH (Ac-SOC(4)) through an amide bond formed between Val(123) carboxylic group of the epitope and the lysine N(epsilon) groups of the carrier (Ac-[Lys(Fas14p)-Aib-Gly](4)-OH). Ac-[Lys(Fas14p)-Aib-Gly](4)-OH failed to readily discriminate between naïve and infected sheep. In contrast, the free peptides reproducibly differentiated between parasite-free sheep, sheep infected with parasites other than Fasciola, and experimentally Fasciola-infected sheep. The data together indicated that the peptides might be of considerable use for discriminating between early and late, and low and high burden, sheep infection with F. gigantica. FasAc14p was chosen to determine whether a peptide based on a critical enzymatic site of cathepsin L proteinase may induce protection against challenge infection. Sheep immunization with FasAc14p peptide induced significant expression of interleukin-4 mRNA, and humoral antibodies that bound to molecule(s) on the intact surface membrane of newly excysted juvenile worms, and mediated their attrition. The immune responses were associated with significant (P < 0.02) decrease of 23.1% in worm recovery, but with no decrease in the size or maturation of worms recovered.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic. jezek@uochb.cas.cz
authors.forename: Jan
authors.initials: J
authors.lastname: Jezek
authors.forename: Rashika
authors.initials: R
authors.lastname: El Ridi
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salah
authors.forename: Amal
authors.initials: A
authors.lastname: Wagih
authors.forename: Haidy W
authors.initials: HW
authors.lastname: Aziz
authors.forename: Hatem
authors.initials: H
authors.lastname: Tallima
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: El Shafie
authors.forename: Tarek Abdel
authors.initials: TA
authors.lastname: Khalek
authors.forename: Faten F Abo
authors.initials: FF
authors.lastname: Ammou
authors.forename: Constantinos
authors.initials: C
authors.lastname: Strongylis
authors.forename: Vassilios
authors.initials: V
authors.lastname: Moussis
authors.forename: Vassilios
authors.initials: V
authors.lastname: Tsikaris
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002403:Cathepsins / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D002851:Chromatography, High Pressure Liquid; D003546:Cysteine Endopeptidases / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D005211:Fascioliasis / Q000517:prevention & control* / Q000662:veterinary; D015801:Helminth Proteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D007159:Immunologic Tests / Q000662:veterinary; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D012756:Sheep; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D015801:Helminth Proteins; D010455:Peptides; D002403:Cathepsins; C086102:cat-L1B protein, Fasciola gigantica; D003546:Cysteine Endopeptidases