Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

Bommana, Sankhya; Walker, Evelyn; Desclozeaux, Marion

doi:10.1371/journal.pone.0188370

Cited by 5 publications

(4 citation statements)

References 30 publications

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“…In this study, we also identified three lambs that were qPCR positive (2/3 lambs were repeatedly qPCR positive) but had no detectable CFT antibodies longitudinally. In our previous study on characterisation of humoral immune responses to naturally occurring C. pecorum infections we have identified moderate antigen specific MOMP and PmpG IgG antibodies present in these three lambs longitudinally ( Bommana et al, 2017 ). These findings elude us to believe that these animals are not passive shedders of C. pecorum and that in reality CFT as an assay has relatively poor sensitivity.…”

Section: Discussionmentioning

confidence: 84%

“…CFT is inappropriate for the retrospective diagnosis of chlamydial mucosal infections, such as in oculo-genital sites that make antibodies specific to a localised site of infection ( Barnes, 1989 ; Griffiths et al, 1996 ). The exception to this is diagnosis of chlamydial polyarthritis or abortion in ruminants, wherein high exposure to Chlamydia elicits a pronounced systemic increase in antibody levels ( Perez-Martinez, Schmeer & Storz, 1986 ; Bommana et al, 2017 ). Potentially, there may exist early seroconversion or antibody markers for improved serological diagnosis of acute-phase infection in livestock, overcoming the shortcomings of CFT.…”

Section: Discussionmentioning

confidence: 99%

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Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

Bommana

Walker

Desclozeaux

et al. 2018

PeerJ

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BackgroundChlamydia pecorum is a globally significant livestock pathogen causing pathology and production losses. The on-farm infection and serological dynamics and the relevance of existing diagnostic tools for diagnosing C. pecorum in livestock remains poorly characterized. In this study, we characterized the antigen and antibody dynamics of this pathogen in a longitudinal study of prime lamb production, utilizing the infection focused C. pecorum-specific 16S rRNA qPCR assay and serology based chlamydial Complement fixation Test (CFT).MethodsThe study consisted of 76 Border Leicester mixed sex lambs (39 females and 37 males) that were sampled bimonthly from 2–10 months of age in a commercial farm operating in Central NSW, Australia. Blood/plasma was analysed for CFT antibodies, and swabs from conjunctival, rectal and vaginal sites were analysed for C. pecorum shedding using qPCR. We assessed the temporal and overall dynamics of C. pecorum in lambs, including detailed description and comparison of qPCR and CFT, the timing of first detection by either diagnostic method, the lag between infection and antibody response; and the distribution of qPCR load and CFT antibody titre over time.ResultsOver the study period, C. pecorum was highly prevalent (71.0% by qPCR, 92.1% by CFT, 96.0% by both), with 21.1% (16/76) lambs shedding ≥1, 000 qPCR copies/µl (denoted as high shedders). C. pecorum shedding (as evidence of infection) were first observed at two months of age (14.4%) with a significant peak of infection occurring at six months of age (34.2%), whereas seroconversions peaked at eight months of age (81.5%). 52.6% of C. pecorum qPCR and CFT positive lambs became qPCR negative by 10 months of age, indicating clearance of chlamydial infection. Although CFT is utilised for on-farm detection of active infection, we confirm that it lagged behind qPCR detection (average lag 1.7 ± 2.1 months) and that the proportion of qPCR positives simultaneously identified by CFT was low with 2/11 (18.1%), 0/13, 17/25 (68.0%), 5/7 (71.4%) and 1/10 (10.0%) concurrent seroconversions occurring at two, four, six, eight and 10 months of age, respectively.DiscussionThis work reveals rapid rates of C. pecorum infection and widespread exposure during lamb production. The comparison of molecular and serological diagnostic agreement longitudinally, supports the use of qPCR as an important ancillary tool for the detection of active infections in conjunction with chlamydial CFT for routine veterinary diagnostics. Development of rapid Point-of-Care (POC) tools for diagnosing active infection would be valuable for producers and veterinarians.

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Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

Bommana

Walker

Desclozeaux

et al. 2018

PeerJ

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“…These 35 sheep were selected following 2 rounds of prescreening for Chlamydia in over 100 sheep, collecting rectal swabs for testing by C. pecorum-specific qPCR (qualitative polymerase chain reaction) as well as blood samples for complement fixation test. 4 Both tests confirmed Chlamydia-negative status in the 35 animals selected for experimental studies. The objectives of the previous study 21 were to (1) establish an infection model of chlamydial arthritis, (2) determine the optimal delivery route, (3) identify potential differences between C. pecorum isolates IPA and E58 in vivo, and (4) observe both infection and recovery phases following infection.…”

Section: Experimental Design and Samplingmentioning

confidence: 80%

Chlamydia pecorum–Induced Arthritis in Experimentally and Naturally Infected Sheep

et al. 2020

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Chlamydia pecorum is an obligate intracellular pathogen with a wide host range including livestock such as sheep, cattle, goats, and pigs as well as wildlife species such as koalas. Chlamydial polyarthritis is an economically important disease resulting in swollen joints, lameness, stiffness, and weight loss in young sheep. In the present study, tissues from sheep experimentally or naturally infected with Chlamydia pecorum were assessed by histopathology and immunohistochemistry. Carpal, hock, and stifle joints as well as spleen, liver, kidney, lymph nodes, lung, and brain of 35 sheep from different inoculation groups were available. Two different C. pecorum strains (IPA and E58), different routes of administration (intraarticular or intravenous), UVA-irradiated IPA strain, and corresponding noninfected control groups were investigated. Similar investigations on tissues from 5 naturally infected sheep were performed. The most obvious inflammatory lesions were observed in synovial tissues and, notably, in the renal pelvis from the experimentally infected group and naturally infected animals. This resulted in chronic or chronic-active arthritis and pyelitis. Intralesional chlamydial inclusions could be demonstrated by immunohistochemistry in both tissues. Immunohistochemical evaluation of the presence and distribution of macrophages, T and B cells in synovial tissues revealed macrophages as the most prevalent inflammatory cell population. Previous observations indicated that C. pecorum isolates can infect circulating monocytes. Together with the finding of the histological lesions in synovial tissues and internal organs alongside the presence of C. pecorum DNA, these observations suggest chlamydial arthritis in lambs is the result of hematogeneous spread of C. pecorum.

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“…Peptide ELISA’s were performed to determine the antibody response to P1 and P2, as described by Bommana et al . (2017) [ 37 ] with the following modifications. Streptavidin plates were initially coated with either, 1.5μg/well of P1 or 1.5μg/well of P2.…”

Section: Methodsmentioning

confidence: 99%

Vaccination of koalas (Phascolarctos cinereus) against Chlamydia pecorum using synthetic peptides derived from the major outer membrane protein

Nyari

Khan

Rawlinson³

et al. 2018

PLoS ONE

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Chlamydia pecorum is a mucosal infection, which causes debilitating disease of the urinary tract, reproductive tract and ocular sites of koalas (Phascolarctos cinereus). While antibiotics are available for treatment, they are detrimental to the koalas’ gastrointestinal tract microflora leaving the implementation of a vaccine as an ideal option for the long-term management of koala populations. We have previously reported on the successes of an anti-chlamydial recombinant major outer membrane protein (rMOMP) vaccine however, recombinant protein based vaccines are not ideal candidates for scale up from the research level to small-medium production level for wider usage. Peptide based vaccines are a promising area for vaccine development, because peptides are stable, cost effective and easily produced. In this current study, we assessed, for the first time, the immune responses to a synthetic peptide based anti-chlamydial vaccine in koalas. Five healthy male koalas were vaccinated with two synthetic peptides derived from C. pecorum MOMP and another five healthy male koalas were vaccinated with full length recombinant C. pecorum MOMP (genotype G). Systemic (IgG) and mucosal (IgA) antibodies were quantified and pre-vaccination levels compared to post-vaccination levels (12 and 26 weeks). MOMP-peptide vaccinated koalas produced Chlamydia-specific IgG and IgA antibodies, which were able to recognise not only the genotype used in the vaccination, but also MOMPs from several other koala C. pecorum genotypes. In addition, IgA antibodies induced at the ocular site not only recognised recombinant MOMP protein but also, whole native chlamydial elementary bodies. Interestingly, some MOMP-peptide vaccinated koalas showed a stronger and more sustained vaccine-induced mucosal IgA antibody response than observed in MOMP-protein vaccinated koalas. These results demonstrate that a synthetic MOMP peptide based vaccine is capable of inducing a Chlamydia-specific antibody response in koalas and is a promising candidate for future vaccine development.

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Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

Cited by 5 publications

References 30 publications

Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

Chlamydia pecorum–Induced Arthritis in Experimentally and Naturally Infected Sheep

Vaccination of koalas (Phascolarctos cinereus) against Chlamydia pecorum using synthetic peptides derived from the major outer membrane protein

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