title: Identification of a surface-exposed immunodominant epitope on outer membrane protein P1 of Haemophilus influenzae type b.
abstract: Eight murine monoclonal antibodies (MAbs) directed against outer membrane protein P1 of Haemophilus influenzae type b were generated and characterized. Seven of the eight MAbs reacted with recombinant P1 and purified P1 protein from H. influenzae type b strains MinnA and 1613; MAb P1.8 was specific for the latter strain. A panel of 32 nontypeable and 140 encapsulated Haemophilus strains recovered worldwide representing the major clonal families of serotypes a, b, and d was used to evaluate the distribution among Haemophilus strains of the epitopes identified by the P1-specific MAbs. The epitope reactive with the seven MAbs which recognized P1 from strains MinnA and 1613 was shared by 92% of the encapsulated Haemophilus isolates tested. The epitope is present in the H. influenzae type b strains from clonal families commonly recovered from cases of invasive disease in North America and Europe. A series of nested 5' and 3' deletions of the P1 gene were constructed and analyzed to localize the determinants on P1 recognized by the MAbs. MAbs P1.2, P1.4, P1.5, P1.6, and P1.7 recognized an epitope localized to the carboxy-terminal portion of P1. Murine MAbs P1.1 and P1.3 and two human MAbs, HiH-7 and HiH-10, recognized a complex epitope which was partially localized to the carboxy-terminal portion of the P1 protein. These data indicate that an immunodominant surface-exposed epitope is present on the carboxy-terminal portion of the P1 protein of type b Haemophilus isolates responsible for the majority of invasive disease in North America.
authors.affiliation: National Laboratory for Immunology, Laboratory Centre for Disease Control, Ottawa, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Proulx
authors.forename: R S
authors.initials: RS
authors.lastname: Munson
authors.forename: S
authors.initials: S
authors.lastname: Grass
authors.forename: J
authors.initials: J
authors.lastname: Hamel
authors.forename: D
authors.initials: D
authors.lastname: Martin
authors.forename: B R
authors.initials: BR
authors.lastname: Brodeur
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D002678:Chimera / Q000235:genetics; D002872:Chromosome Deletion; D000939:Epitopes / Q000276:immunology; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology*; D016130:Immunophenotyping; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010957:Plasmids; D011994:Recombinant Proteins
chemical_list: D000911:Antibodies, Monoclonal; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins; C067559:outer membrane protein P1, Haemophilus influenzae type b