title: Genetic diversity of Chlamydia pecorum strains in wild koala locations across Australia and the implications for a recombinant C. pecorum major outer membrane protein based vaccine.
abstract: The long term survival of the koala (Phascolarctos cinereus) is at risk due to a range of threatening processes. A major contributing factor is disease caused by infection with Chlamydia pecorum, which has been detected in most mainland koala populations and is associated with ocular and genital tract infections. A critical aspect for the development of vaccines against koala chlamydial infections is a thorough understanding of the prevalence and strain diversity of C. pecorum infections across wild populations. In this study, we describe the largest survey (403 koalas from eight wild populations and three wildlife hospitals) examining the diversity of C. pecorum infections. 181 of the 403 koalas tested (45%) positive for C. pecorum by species-specific quantitative PCR with infection rates ranging from 20% to 61% in the eight wild populations sampled. The ompA gene, which encodes the chlamydial major outer membrane protein (MOMP), has been the major target of several chlamydial vaccines. Based on our analysis of the diversity of MOMP amino types in the infected koalas, we conclude that, (a) there exists significant diversity of C. pecorum strains in koalas, with 10 distinct, full length C. pecorum MOMP amino types identified in the 11 koala locations sampled, (b) despite this diversity, there are predicted T and B cell epitopes in both conserved as well as variable domains of MOMP which suggest cross-amino type immune responses, and (c) a recombinant MOMP-based vaccine consisting of MOMP "F" could potentially induce heterotypic protection against a range of C. pecorum strains.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove 4059, Australia.
authors.forename: Avinash
authors.initials: A
authors.lastname: Kollipara
authors.forename: Adam
authors.initials: A
authors.lastname: Polkinghorne
authors.forename: Charles
authors.initials: C
authors.lastname: Wan
authors.forename: Pride
authors.initials: P
authors.lastname: Kanyoka
authors.forename: Jon
authors.initials: J
authors.lastname: Hanger
authors.forename: Joanne
authors.initials: J
authors.lastname: Loader
authors.forename: John
authors.initials: J
authors.lastname: Callaghan
authors.forename: Alicia
authors.initials: A
authors.lastname: Bell
authors.forename: William
authors.initials: W
authors.lastname: Ellis
authors.forename: Sean
authors.initials: S
authors.lastname: Fitzgibbon
authors.forename: Alistar
authors.initials: A
authors.lastname: Melzer
authors.forename: Kenneth
authors.initials: K
authors.lastname: Beagley
authors.forename: Peter
authors.initials: P
authors.lastname: Timms
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001315:Australia; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology; D002689:Chlamydia / Q000145:classification / Q000235:genetics*; D002690:Chlamydia Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018985:Epitopes, B-Lymphocyte / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000378:metabolism; D014644:Genetic Variation; D008969:Molecular Sequence Data; D048368:Phascolarctidae / Q000276:immunology / Q000382:microbiology*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012641:Selection, Genetic; D017385:Sequence Homology; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D014614:Vaccines, Synthetic
keywords: Amino type; Chlamydia pecorum; Diversity; Koala; MOMP; ompA