Intratracheal infection as an efficient route for testing vaccines against Chlamydia abortus in sheep

Álvarez, D.; Salinas, J.; Buendía, A. J.; Ortega, Nieves; Rı́o, Laura Del; Sánchez, J.; Navarro, J. A.; Gallego, María Soledad Carrillo; Murcia-Belmonte, A.; Cuello, F.; Caro, M.R.

doi:10.1016/j.tvjl.2015.04.036

Cited by 6 publications

(5 citation statements)

References 34 publications

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“…However, given the zoonotic nature of the microorganism, and the recent description of outbreaks of abortions in vaccinated flocks in which a vaccine strain was implicated (16, 17), this commercially available attenuated vaccine pose safety concerns. By contrast, inactivated vaccines, prepared from egg-grown strains or cell cultures, have been widely used in the control of EAE since its infection nature was discovered in the 1950s, and its efficacy has been well documented (4, 18–21), leading to its recommendation as a useful control option by the OIE (14). However, although inactivated vaccines may reduce the abortion rate, they do not completely prevent bacterial shedding and reproductive failures may still occur (9).…”

Section: Introductionmentioning

confidence: 99%

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

et al. 2016

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Ovine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination, and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators of vaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life). Three groups of ewes [control non-vaccinated, C (n = 18); vaccinated with standard dose, SV (n = 16); and vaccinated with 1/2 dose, DV (n = 17)], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs) and ELISA (serum) until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 kg (p = 0.056) and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared with controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of enzootic abortion of ewes-commercial vaccines.

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Section: Introductionmentioning

confidence: 99%

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

et al. 2016

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“…However, there is no previous published evidence that C. abortus can infect the human respiratory tract. Previous published research involving experimental infections with C. abortus has identified the ability of this pathogen to cause pulmonary disease in animal species such as sheep [ 9 , 15 ], calves [ 16 ] and mice [ 17 ]. The detection of C. abortus in a broncho-alvolar lavage (BAL) would have been decisive to firmly confirm the etiological agent of the process.…”

Section: Discussionmentioning

confidence: 99%

“…The patient worked as a veterinary researcher in a laboratory where experimental intranasal infections with C. abortus were developed in sheep. The patient carried out these infections using a suspension of C. abortus sprayed into both nostrils with a multi-dose spray pump, as described previously [ 9 ]. Ten days after the sheep infections, the patient showed the first symptoms.…”

Section: Case Presentationmentioning

confidence: 99%

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Isolation of Chlamydia abortus from a laboratory worker diagnosed with atypical pneumonia

et al. 2015

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BackgroundIdentifying the aetiological agent of atypical pneumonia in human can sometimes be a tedious process, especially in cases where Mycoplasma pneumoniae, Legionella species and Chlamydia pneumoniae are ruled out. In such cases, a correct anamnesis of the patient is basic to clarify which pathogens might have produced the infection. For this reason, health professionals including veterinarians and laboratory personnel working with zoonotic pathogens should keep their doctors informed.Case presentationA human case of atypical pneumonia linked to Chlamydia abortus is reported. A 47-year-old male, a veterinarian researcher into chlamydiae, developed respiratory symptoms, breathing problems and high fever. Serological analyses ruled out the involvement of several respiratory pathogens, such as M. pneumoniae, Legionella pneumophila, Rickettsia conorii and C. pneumoniae, and Chlamydia abortus was identified as the possible aetiological agent of the infection. The isolation of C. abortus from the patient’s sputum and subsequent molecular analysis confirmed the presence of this microorganism.ConclusionAs far as we know, although C. abortus has not been previously described as capable of causing pneumonia in humans, this is the first reported case of atypical pneumonia in which C. abortus is thought to have played an aetiological role.

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“…Mice were vaccinated with an experimental inactivated vaccine previously tested and validated in our laboratory using mouse models [7] and ovine models [36,37]) using a purified derivate of saponin (QS21; Agenus) as adjuvant. The vaccine was prepared according to the protocol described by [38].…”

Section: Phase 2 Vaccination Hormone Treatment and Infection Of Micementioning

confidence: 99%

Effect of Female Sex Hormones on the Immune Response against Chlamydia abortus and on Protection Conferred by an Inactivated Experimental Vaccine in a Mouse Model

et al. 2022

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Mice are valuable models extensively used to test vaccine candidates against Chlamydia abortus and to clarify immunopathological mechanisms of the bacteria. As this pathogen has the ability to reactivate during pregnancy, it is important to deepen the knowledge and understanding of some of the effects of female hormones on immunity and vaccination. This study is aimed at describing the role of sex hormones in the pathology of OEA during chlamydial clearance using ovariectomised mice and also gaining an understanding of how 17β-oestradiol or progesterone may impact the effectiveness of vaccination. Animals were treated with sex hormones and infected with C. abortus, and the kinetics of infection and immune response were analysed by means of bacterial isolation, histopathology, and immunohistochemistry. In a second phase of the study, protection conferred by an experimental vaccine after hormone treatment was assessed. Oestradiol showed a stimulatory effect on the immune response during infection, with a more efficient recruitment of macrophages and T-cells at the infection site. Furthermore, after vaccination, oestradiol-treated animals showed a stronger protection against infection, indicating that this hormone has a positive effect, stimulating a specific memory response to the pathogen.

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Intratracheal infection as an efficient route for testing vaccines against Chlamydia abortus in sheep

Cited by 6 publications

References 34 publications

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

Isolation of Chlamydia abortus from a laboratory worker diagnosed with atypical pneumonia

Effect of Female Sex Hormones on the Immune Response against Chlamydia abortus and on Protection Conferred by an Inactivated Experimental Vaccine in a Mouse Model

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