title: Lack of antiviral antibody response in koalas infected with koala retroviruses (KoRV).
abstract: Many wild koalas are infected with the koala retrovirus, KoRV, some of which suffer from lymphoma and chlamydial disease. Three subgroups, KoRV-A, KoRV-B and KoRV-J, have so far been described. It is well known that other closely related gammaretroviruses can induce tumours and severe immunodeficiencies in their respective hosts and a possible role for KoRV infection in lymphoma and chlamydial disease in koalas has been suggested. In many wild koalas, KoRV-A has become endogenised, i.e., it is integrated in the germ-line and is passed on with normal cellular genes. In this study, sera from koalas in European zoos and from wild animals in Australia were screened for antibodies against KoRV-A. These naturally infected animals all carry endogenous KoRV-A and two zoo animals are also infected with KoRV-B. The antibody response is generally an important diagnostic tool for detecting retrovirus infections. However, when Western blot analyses were performed using purified virus or recombinant proteins corresponding to KoRV-A, none of the koalas tested positive for specific antibodies, suggesting a state of tolerance. These results have implications for koala vaccination, as they suggest that therapeutic immunisation of animals carrying and expressing endogenous KoRV-A will not be successful. However, it remains unclear whether these animals can be immunised against KoRV-B and immunisation of uninfected koalas could still be worthwhile.
authors.affiliation: Robert Koch Institute, HIV and Other Retroviruses, Nordufer 20, 13353 Berlin, Germany. Electronic address: UweFiebig@gmx.de.
authors.forename: Uwe
authors.initials: U
authors.lastname: Fiebig
authors.affiliation: Robert Koch Institute, HIV and Other Retroviruses, Nordufer 20, 13353 Berlin, Germany. Electronic address: KellerM@rki.de.
authors.forename: Martina
authors.initials: M
authors.lastname: Keller
authors.affiliation: Robert Koch Institute, HIV and Other Retroviruses, Nordufer 20, 13353 Berlin, Germany. Electronic address: AnneMoeller@gmx.de.
authors.forename: Annekatrin
authors.initials: A
authors.lastname: Möller
authors.affiliation: University of the Sunshine Coast, Locked Bag 4, 4558 Maroochydore DC, Queensland, Australia. Electronic address: ptimms@usc.edu.au.
authors.forename: Peter
authors.initials: P
authors.lastname: Timms
authors.affiliation: Robert Koch Institute, HIV and Other Retroviruses, Nordufer 20, 13353 Berlin, Germany. Electronic address: DennerJ@rki.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Denner
mesh_terms: D000818:Animals; D000835:Animals, Wild; D000836:Animals, Zoo; D000914:Antibodies, Viral / Q000097:blood*; D000917:Antibody Formation; D001315:Australia; D015153:Blotting, Western; D005060:Europe; D007108:Immune Tolerance; D048368:Phascolarctidae; D012190:Retroviridae / Q000276:immunology*; D012192:Retroviridae Infections / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral
keywords: Antibody response; Koala retrovirus; Retroviruses; Vaccine