Polymorphism of the major surface epitope of the CopB outer membrane protein ofMoraxella catarrhalis

Abstract

The CopB outer membrane protein has been considered a vaccine candidate for the prevention of infections due to Moraxella catarrhalis. Monoclonal antibody 10F3 recognizes whole cells of about 70% of clinical isolates, suggesting that this epitope is reasonably conserved. To determine whether CopB has other surface epitopes, we analyzed M. catarrhalis isolates using polyclonal sera against recombinant CopB proteins from a 10F3 positive isolate and a 10F3 negative isolate, and polyclonal sera against synthetic peptides that contained the sequence corresponding to the 10F3 epitope region of three different isolates. Extensive cross-reactivity was observed with the anti-CopB sera towards purified recombinant CopB proteins in Western blot and antigen ELISA, implying that antigenic regions common to both proteins were present. However, anti-CopB sera resembled anti-CopB peptide sera in exhibiting similar binding specificity to whole cells, segregating M. catarrhalis isolates into four CopB groups. We subsequently cloned and sequenced the copB genes from representative isolates. The deduced CopB amino acid sequences and the degree of sequence identity also demonstrated the existence of the same four CopB groups. Each of the four groups had a unique sequence in the 10F3 epitope region and a fifth group had the epitope deleted. The polymorphism of the major surface epitope prompts further consideration regarding the utility of CopB as a vaccine component as well as the design of an efficacious CopB-based vaccine to achieve broad protection against Moraxella infection.

Moraxella catarrhalisOuter Membrane Protein CD Elicits Antibodies That Inhibit CD Binding to Human Mucin and Enhance Pulmonary Clearance ofM. catarrhalisin a Mouse Model

“…4A). Bovine serum albumin and the purified recombinant CopB protein (rCopB) of M. catarrhalis (23), included as negative controls, did not display affinity to mucin. To assess functional characteristics of the antisera against CD, their effects on the CD-mucin binding activity were examined.…”

A shared antigen among Vibrio species: Outer membrane protein-OmpK as a versatile Vibriosis vaccine candidate in Orange-spotted grouper (Epinephelus coioides)

“…It was possible reason that high degree of identities had the same or more similar epitopes and strongly immune response were induced. It was reported that the degree of sequence identity of CopB affected the polymorphism of the major surface epitopes in Moraxella catarrhalis [19].…”

Age-related genotypic and phenotypic differences in Moraxella catarrhalis isolates from children and adults presenting with respiratory disease in 2001–2002

“…Five units of RsaI (copB) or 5 units of BseJI (ompCD) were used per reaction mix, incubated at 37 uC or 65 uC, respectively. The copB PCR RFLP typing method was based upon sequence data published by Liu et al (2006) but cannot distinguish between CopB types I and III (Liu et al, 2006). Expected visible product sizes were: 374 and 157 bp for CopB type 0; 342 and 157 bp for CopB types I/III; 332 and 187 bp for CopB type II; and 519 bp for CopB type IV.…”