Vaccination of healthy and diseased koalas (Phascolarctos cinereus) with a Chlamydia pecorum multi-subunit vaccine: Evaluation of immunity and pathology

Abstract

Chlamydial infections represent a major threat to the long-term survival of the koala and a successful vaccine would provide a valuable management tool. Vaccination however has the potential to enhance inflammatory disease in animals exposed to a natural infection prior to vaccination, a finding in early human and primate trials of whole cell vaccines to prevent trachoma. In the present study, we vaccinated both healthy koalas as well as clinically diseased koalas with a multi-subunit vaccine consisting of Chlamydia pecorum MOMP and NrdB mixed with immune stimulating complex as adjuvant. Following vaccination, there was no increase in inflammatory pathological changes in animals previously infected with Chlamydia. Strong antibody (including neutralizing antibodies) and lymphocyte proliferation responses were recorded in all vaccinated koalas, both healthy and clinically diseased. Vaccine induced antibodies specific for both vaccine antigens were observed not only in plasma but also in ocular secretions. Our data shows that an experimental chlamydial vaccine is safe to use in previously infected koalas, in that it does not worsen infection-associated lesions. Furthermore, the prototype vaccine is effective, as demonstrated by strong levels of neutralizing antibody and lymphocyte proliferation responses in both healthy and clinically diseased koalas. Collectively, this work illustrates the feasibility of developing a safe and effective Chlamydia vaccine as a tool for management of disease in wild koalas.

Oral health in South East Queensland Koalas: Prevalence of periodontal disease and other pathologies

“…Anthropogenic research into Australian history includes descriptive information on lifestyle, reproduction and territorial ranges of the marsupials including the koala. Current disease research is making a concerted effort to develop improved chlamydia therapies (Carey et al, 2010, Kollipara et al, 2012, Govendir et al, 2015, Kimble et al, 2013.…”

Systemic Antibody Response to Chlamydia Trachomatis Infection in Patients Either Infected or Reinfected with Different Chlamydia Serovars

“…[18] In brief, ~30 µg of purified EBs was loaded on 0.75 mm-wide 12% sodium dodecyl sulphate-polyacrylamide gel electrophoresis gels (110 V for 1 h). Following transfer to a nitrocellulose membrane (Pall Corporation, Australia) at 90 V for 1 h, membranes were blocked for non-specific binding in blocking buffer (5% skimmed milk in 1× Tris-buffered saline) overnight at 4°C or for 2 h at room temperature.…”

“…In vitro neutralisation assay was performed using individual's serum samples collected at two different time points (individual with single and repeated infection) as well as single time point, according to Kollipara et al [18] Both cells and inclusions were counted under the microscope, and a mean of ten fields of view for each well was counted and the neutralisation percentage was determined and compared to media-only controls.…”

Animal Models of Immunity to Female Genital Tract Infections and Vaccine Development

“…MOMP is the most extensively studied antigen (Farris and Morrison, 2011) and has been used in several forms, including as part of an extracted outer membrane complex, as purified native MOMP (nMOMP) extracted from EBs, as a recombinant protein (rMOMP), and in various plasmids in studies of DNA vaccination. Immunization with MOMP, using various adjuvants and routes of immunization, elicits antibody and cell-mediated immunity and provides partial protection against infection and pathology in mice, guinea pigs, koalas, and nonhuman primates (Berry et al, 2004;Skelding et al, 2006;Schautteet et al, 2012;Kollipara et al, 2012;Andrew et al, 2011). Protection similar to that provided by a previous IN infection was obtained after parenteral immunization with nMOMP combined with CpG1826 and Montanide ISA 720 adjuvants (Pal et al, 2005) and incorporation of rMOMP into vault nanoparticles delivered intranasally (Champion et al, 2009).…”

“…Although DC-based vaccines that are tailored to each individual are impractical for a chlamydial vaccine, they provide insight into the types of immunity an adjuvant would need to induce and indicate that appropriate activation of DCs to elicit Th1 and antibody responses is key to inducing protective immunity. Adjuvants evaluated for chlamydial vaccines include Alum; Freund's adjuvants; bacterial ADP-ribosylating toxins (cholera toxin (CT), ET) and their derivatives (CT-B, CTA1-DD); the outer surface protein of Borrelia burgdorferi OspA; Lipid C/Liporale; particle-based adjuvant systems such as liposomes (DDA-TDB/CAF01, DDA-MPL), vault nanoparticles, and Vibrio cholerae ghosts; and adjuvants already in human clinical trials such as CpG, Montanide, LT-R72, MF-59, LT-K63, ISCOMs/immunostimulating complex, GM-CSF, and IL-12 (Farris and Morrison, 2011;Kollipara et al, 2012;Hickey et al, 2005). Many of these adjuvants elicit varying levels of protection against infection and upper tract pathology in mice, although sterilizing immunity has not yet been achieved.…”