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Richardson S, Bell CR, Medhavi F, Tanner T, Lundy S, Omosun Y, Igietseme JU, Eko FO. A novel cold-chain free VCG-based subunit vaccine protects against Chlamydia abortus-induced neonatal mortality in a pregnant mouse model. Front Immunol 2023; 14:1243743. [PMID: 37915580 PMCID: PMC10616880 DOI: 10.3389/fimmu.2023.1243743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
Chlamydia abortus (Cab) causes spontaneous abortion and neonatal mortality in infected ruminants and pregnant women. Most Cab infections are asymptomatic, although they can be treated with antibiotics, signifying that control of these infections may require alternative strategies, including the use of effective vaccines. However, the limitations imposed by live attenuated and inactivated vaccines further suggest that employment of subunit vaccines may need to be considered. The efficacy of a newly generated Vibrio cholerae ghost (rVCG)-based subunit vaccine harboring the N-terminal portion of the Cab Pmp18D protein (rVCG-Pmp18.3) in preventing Cab-induced abortion or neonatal mortality was evaluated in pregnant mice. Mice were intranasally (IN) immunized and boosted twice, 2 weeks apart with the vaccine, and immunized and unimmunized mice were caged with males 4 weeks postimmunization. The mice were then infected either IN or transcervically (TC) 10 days after pregnancy, and the fertility rate was determined 7 days postpartum. Eight days after delivery, the mice were sacrificed, and Cab infectivity in the lungs and spleens was evaluated by culturing tissue homogenates in tissue culture. Our results demonstrated that the vaccine induced immune effectors that mediated complete clearance of infection in the lungs and significantly reduced Cab infectivity in the spleen following IN immunization. Vaccine immunization also afforded protection against Cab-induced upper genital tract pathology (uterine dilation). Furthermore, while there was no incidence of abortion in both immunized and unimmunized mice, immunized mice were completely protected against neonatal mortality compared to unimmunized infected controls, which lost a significant percentage of their litter 7 days postpartum. Our results establish the capability of the rVCG-Pmp18.3 vaccine to prevent infection in the lungs (mucosal) and spleen (systemic) and protect mice from Cab-induced tubal pathologies and neonatal mortality, a hallmark of Cab infection in ruminants. To advance the commercial potential of this vaccine, future studies will optimize the antigen dose and the number of vaccine doses required for protection of ruminants.
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Affiliation(s)
- Shakyra Richardson
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Courtnee R. Bell
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Fnu Medhavi
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Tayhlor Tanner
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Stephanie Lundy
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Yusuf Omosun
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
| | - Joseph U. Igietseme
- National Center for Emerging Zoonotic and Infectious Diseases, Center for Disease Control and Prevention (CDC), Atlanta, GA, United States
| | - Francis O. Eko
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States
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Livingstone M, Wattegedera SR, Palarea-Albaladejo J, Aitchison K, Corbett C, Sait M, Wilson K, Chianini F, Rocchi MS, Wheelhouse N, Entrican G, Longbottom D. Efficacy of Two Chlamydia abortus Subcellular Vaccines in a Pregnant Ewe Challenge Model for Ovine Enzootic Abortion. Vaccines (Basel) 2021; 9:vaccines9080898. [PMID: 34452023 PMCID: PMC8402522 DOI: 10.3390/vaccines9080898] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 11/24/2022] Open
Abstract
Chlamydia abortus, the aetiological agent of enzootic abortion of ewes, is a major cause of reproductive loss in small ruminants worldwide, accounting for significant economic losses to the farming industry. Disease can be managed through the use of commercial inactivated or live whole organism-based vaccines, although both have limitations particularly in terms of efficacy, safety and disease-associated outbreaks. Here we report a comparison of two experimental vaccines (chlamydial outer membrane complex (COMC) and octyl glucoside (OG)-COMC) based on detergent extracted outer membrane preparations of C. abortus and delivered as prime-boost immunisations, with the commercial live vaccine Cevac® Chlamydia in a pregnant sheep challenge model. No abortions occurred in either experimental vaccine group, while a single abortion occurred in the commercial vaccine group. Bacterial shedding, as a measure of potential risk of transmission of infection to naïve animals, was lowest in the COMC vaccinated group, with reductions of 87.5%, 86.4% and 74% observed for the COMC, OG-COMC and live commercial vaccine groups, respectively, compared to the unvaccinated challenge control group. The results show that the COMC vaccine performed the best and is a safer efficacious alternative to the commercial vaccines. However, to improve commercial viability, future studies should optimise the antigen dose and number of inoculations required.
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Affiliation(s)
- Morag Livingstone
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Sean Ranjan Wattegedera
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | | | - Kevin Aitchison
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Cecilia Corbett
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Michelle Sait
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Kim Wilson
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Francesca Chianini
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Mara Silvia Rocchi
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Nicholas Wheelhouse
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - Gary Entrican
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
| | - David Longbottom
- Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK; (M.L.); (S.R.W.); (K.A.); (C.C.); (M.S.); (K.W.); (F.C.); (M.S.R.); (N.W.); (G.E.)
- Correspondence:
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Montbrau C, Fontseca M, March R, Sitja M, Benavides J, Ortega N, Caro MR, Salinas J. Evaluation of the Efficacy of a New Commercially Available Inactivated Vaccine Against Ovine Enzootic Abortion. Front Vet Sci 2020; 7:593. [PMID: 33102549 PMCID: PMC7499823 DOI: 10.3389/fvets.2020.00593] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/23/2020] [Indexed: 01/11/2023] Open
Abstract
Ovine enzootic abortion (OEA), caused by Chlamydia abortus, is an economically important disease in many countries. Inactivated vaccines have been used for many years as they induce immunity in sheep, although outbreaks of abortions have been described in vaccinated flocks. In addition, there is a commercially available live attenuated vaccine that provides good protective results. Recently however, reports question the attenuation of this vaccine and associate it with the appearance of outbreaks of OEA in vaccinated flocks. In the present study, a recently commercialized inactivated vaccine (INMEVA®; Laboratorios Hipra S.A., Amer, Spain) has been evaluated using mouse and sheep experimental models. In the mouse models (non-pregnant and pregnant models), the efficacy of INMEVA vaccine has been compared to an unvaccinated control group and to an experimental inactivated vaccine considered as a positive protection control (UMU vaccine). In the non- pregnant model, the UMU vaccine was more effective than the INMEVA vaccine regarding the impact on body weight or the presence of C. abortus in the liver, but both vaccinated groups (UMU and INMEVA) had significantly lower C. abortus in the liver compared to the control group. In the pregnant model in terms of reproductive failures, pups per mouse or the presence of C. abortus in the liver or uterus, no significant differences were found between both vaccines, inducing protection compared to the control group. In the ovine pregnant model, where INMEVA vaccine was compared only to an unvaccinated group, the results indicate that this new commercial vaccine is safe and provides a suitable level of protection against an experimental challenge with C. abortus. A 75% reduction in reproductive disorders, 55% reduction in animals with C. abortus shedding on day of parturition/abortion, and a significant reduction of the average amount of chlamydial shedding from parturition/abortion over the next 21 days was observed, in relation to the infected control group. The results suggest that this vaccine is adequate for the control and prevention of OEA; however, future studies are necessary to elucidate the type of protective immune response that it induces.
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Affiliation(s)
| | | | | | | | - Julio Benavides
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain
| | - Nieves Ortega
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
| | - María Rosa Caro
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
| | - Jesús Salinas
- Department of Animal Health, Faculty of Veterinary, Mare Nostrum International University of Murcia, Murcia, Spain
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O’Neill LM, O’Driscoll Á, Markey B. Comparison of three commercial serological tests for the detection of Chlamydia abortus infection in ewes. Ir Vet J 2018; 71:13. [PMID: 29854397 PMCID: PMC5975472 DOI: 10.1186/s13620-018-0124-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 05/10/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND 20.9% of diagnosable abortions in Ireland in 2015 were caused by Chlamydia abortus infection. Abortion usually occurs in the last 2-3 weeks of gestation, and up to 30% of ewes may be affected in naïve flocks. Serological diagnosis of EAE in flocks using LPS or whole bacteria as antigens is often hindered by cross reactions with C. pecorum. Although the complement fixation test is the official test for diagnosis of EAE, more sensitive and specific ELISA based tests have been developed. This study aimed to compare three commercial ELISA kits to detect C. abortus antibodies in ewes and to determine which of the kits had the highest sensitivity. The IDvet kit utilises a MOMP peptide antigen, the MVD-Enfer kit is based on a POMP90-3 antigen while the LSI kit plates are coated with chlamydial LPS. The study also aimed to examine the potential of these ELISAs to distinguish infected animals that go on to abort compared to those that have live lambs. Ewes were vaccinated with either a commercial live vaccine (n = 10) or Tris-buffer sham inoculation (n = 9) 5 months prior to gestation, these ewes were then challenged with C. abortus (1 × 106 IFU/ml) on day 90 of gestation. Sera were collected at pre-vaccination, 14 days post vaccination, 35 days post vaccination, pre-challenge, 35 days post challenge and 3 weeks post lambing/abortion (~ 70 days post challenge) and tested using the 3 aforementioned ELISAs to determine if one ELISA was more sensitive at detecting circulating anti-chlamydial antibodies. RESULTS Sensitivity was highest with the LSI test kit at 94.74%, followed by the MVD-Enfer and IDvet kits, at 78.95 and 73.68% respectively. Ewes vaccinated with Enzovax became seropositive at 14 days post vaccination with all kits. Following challenge at day 90 of gestation, antibody titres steadily rose in all groups of ewes. With all ELISA kits, antibody levels were higher in ewes that aborted compared to ewes that had live lambs at 35 days post challenge and three weeks post lambing, and statistically significantly higher antibody levels were recorded in ewes that aborted compared to ewes that had live lambs using the MVD-ENFER ELISA at three weeks post lambing (P = 0.0482). CONCLUSIONS The LSI assay was the most sensitive out of the three kits tested in this study, when sera were tested at three weeks post lambing. As the LPS used in this kit is cross-reactive with all chlamydia, it is good for identifying flocks infected with any chlamydial species, but it is not considered specific for C. abortus. Furthermore, antibody levels were higher in ewes that aborted compared to ewes that had live lambs, at both 35 days post challenge and at three weeks post lambing. Future work should include evaluation of a larger number of sera at a wider range of time-points as well as an estimation of the specificity of commercially available assays.
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Affiliation(s)
- L. M. O’Neill
- School of Veterinary Medicine, University College Dublin, Room 07A, Belfield, Dublin 4, Ireland
| | - Á. O’Driscoll
- School of Veterinary Medicine, University College Dublin, Room 07A, Belfield, Dublin 4, Ireland
| | - B. Markey
- School of Veterinary Medicine, University College Dublin, Room 07A, Belfield, Dublin 4, Ireland
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