title: Epitope mapping and features of the epitope for monoclonal antibodies inhibiting enzymatic activity of Helicobacter pylori urease.
abstract: Two characteristic monoclonal antibodies (HpU-2 and -18) out of 26 monoclonal antibodies (HpU-1 approximately 26) produced against Helicobacter pylori (H. pylori) urease showed a strong inhibitory effect against the enzymatic activity of the urease. Epitope mapping about some monoclonal antibodies of the HpU-series inhibiting enzymatic activity was performed by using a surface plasmon resonance apparatus and by digesting H. pylori urease with trypsin, followed by mass spectroscopy. The sequences of the epitopes recognized by HpU-2 and -18 were SVELIDIGGNRRIFGFNALVDR (22 mer) and IFGFNALVDR (10 mer), respectively. The former sequence is present as a part of a loop structure at a position close to the C-terminal of the alpha-subunit of H. pylori urease, although it has been suggested that the active site of the urease resides in the beta-subunit. The above peptide (22 mer) was chemically synthesized in a linear and cyclic form, and its conjugate with BSA was immunized in rabbits. The resultant serum induced by the linear form could specifically bind to H. pylori infecting human gastric mucosa. These results suggest that the above sequence (22 mer) must be an important epitope, although it locates in the alpha-subunit but not in the beta-subunit.
authors.affiliation: Fukuyama Medical Laboratory Company, Fukuyama-city, Hiroshima 720-8510, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Fujii
authors.forename: Fumiko
authors.initials: F
authors.lastname: Morihara
authors.forename: Takashi
authors.initials: T
authors.lastname: Oku
authors.forename: Emi
authors.initials: E
authors.lastname: Hifumi
authors.forename: Taizo
authors.initials: T
authors.lastname: Uda
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D000918:Antibody Specificity; D018604:Epitope Mapping / Q000379:methods; D000939:Epitopes / Q000276:immunology*; D005753:Gastric Mucosa / Q000382:microbiology; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D007106:Immune Sera; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry / Q000276:immunology; D011487:Protein Conformation; D011817:Rabbits; D014510:Urease / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007106:Immune Sera; D010456:Peptides, Cyclic; D014510:Urease