Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model
Background/Objective: <i>Chlamydia abortus</i>, the cause of ovine enzootic abortion, is a zoonotic bacterial pathogen and one of the most infectious causes of foetal death in sheep worldwide. Although the disease can be controlled using commercial inactivated and live whole-organism vac...
Saved in:
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Vaccines |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-393X/13/1/89 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832587373548929024 |
|---|---|
| author | Morag Livingstone Kevin Aitchison Javier Palarea-Albaladejo Francesco Ciampi Clare Underwood Antonia Paladino Francesca Chianini Gary Entrican Sean Ranjan Wattegedera David Longbottom |
| author_facet | Morag Livingstone Kevin Aitchison Javier Palarea-Albaladejo Francesco Ciampi Clare Underwood Antonia Paladino Francesca Chianini Gary Entrican Sean Ranjan Wattegedera David Longbottom |
| author_sort | Morag Livingstone |
| collection | DOAJ |
| description | Background/Objective: <i>Chlamydia abortus</i>, the cause of ovine enzootic abortion, is a zoonotic bacterial pathogen and one of the most infectious causes of foetal death in sheep worldwide. Although the disease can be controlled using commercial inactivated and live whole-organism vaccines, there are issues with both, particularly concerning efficacy and safety. Recently, we have described the development of a new COMC (chlamydial outer membrane complex) vaccine based on a detergent-extracted outer membrane protein preparation of the pathogen, which can be delivered in a single inoculation and is both efficacious and safe. Methods: In this study, we have evaluated the COMC vaccine further in a dose–response titration of the chlamydial antigen content of the vaccine (from 20 to 2.5 µg in seven experimental groups) using an established pregnant sheep challenge model. Results: No obvious dose–response relationship was observed across the groups, with a single abortion event occurring in four of the groups and three in the lowest dose group (2.5 µg). No abortions occurred in the 15 and 10 µg groups. The abortion rates (0–14%) were significantly below that of the challenge control group (33%). A similar reduction in bacterial shedding of infectious organisms following parturition was observed in the vaccinated groups compared to the challenge control group, which is important in terms of reducing potential transmission to naive animals. Conclusions: The results show that a dose of 10 µg antigen in the vaccine will be optimal in terms of maximising efficacy, reducing shedding at parturition, and ensuring it is cost-effective to produce for commercial manufacture. |
| format | Article |
| id | doaj-art-9bf94746acb14fbcbcc45c1f0e155c0f |
| institution | Kabale University |
| issn | 2076-393X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Vaccines |
| spelling | doaj-art-9bf94746acb14fbcbcc45c1f0e155c0f2025-01-24T13:51:54ZengMDPI AGVaccines2076-393X2025-01-011318910.3390/vaccines13010089Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge ModelMorag Livingstone0Kevin Aitchison1Javier Palarea-Albaladejo2Francesco Ciampi3Clare Underwood4Antonia Paladino5Francesca Chianini6Gary Entrican7Sean Ranjan Wattegedera8David Longbottom9Moredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKBiomathematics and Statistics Scotland, Edinburgh EH9 3FD, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKMoredun Research Institute, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UKBackground/Objective: <i>Chlamydia abortus</i>, the cause of ovine enzootic abortion, is a zoonotic bacterial pathogen and one of the most infectious causes of foetal death in sheep worldwide. Although the disease can be controlled using commercial inactivated and live whole-organism vaccines, there are issues with both, particularly concerning efficacy and safety. Recently, we have described the development of a new COMC (chlamydial outer membrane complex) vaccine based on a detergent-extracted outer membrane protein preparation of the pathogen, which can be delivered in a single inoculation and is both efficacious and safe. Methods: In this study, we have evaluated the COMC vaccine further in a dose–response titration of the chlamydial antigen content of the vaccine (from 20 to 2.5 µg in seven experimental groups) using an established pregnant sheep challenge model. Results: No obvious dose–response relationship was observed across the groups, with a single abortion event occurring in four of the groups and three in the lowest dose group (2.5 µg). No abortions occurred in the 15 and 10 µg groups. The abortion rates (0–14%) were significantly below that of the challenge control group (33%). A similar reduction in bacterial shedding of infectious organisms following parturition was observed in the vaccinated groups compared to the challenge control group, which is important in terms of reducing potential transmission to naive animals. Conclusions: The results show that a dose of 10 µg antigen in the vaccine will be optimal in terms of maximising efficacy, reducing shedding at parturition, and ensuring it is cost-effective to produce for commercial manufacture.https://www.mdpi.com/2076-393X/13/1/89<i>Chlamydia abortus</i>ovine enzootic abortionvaccine developmentvaccine efficacyquantitative real-time PCRserological analysis |
| spellingShingle | Morag Livingstone Kevin Aitchison Javier Palarea-Albaladejo Francesco Ciampi Clare Underwood Antonia Paladino Francesca Chianini Gary Entrican Sean Ranjan Wattegedera David Longbottom Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model Vaccines <i>Chlamydia abortus</i> ovine enzootic abortion vaccine development vaccine efficacy quantitative real-time PCR serological analysis |
| title | Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model |
| title_full | Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model |
| title_fullStr | Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model |
| title_full_unstemmed | Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model |
| title_short | Protective Efficacy of Decreasing Antigen Doses of a <i>Chlamydia abortus</i> Subcellular Vaccine Against Ovine Enzootic Abortion in a Pregnant Sheep Challenge Model |
| title_sort | protective efficacy of decreasing antigen doses of a i chlamydia abortus i subcellular vaccine against ovine enzootic abortion in a pregnant sheep challenge model |
| topic | <i>Chlamydia abortus</i> ovine enzootic abortion vaccine development vaccine efficacy quantitative real-time PCR serological analysis |
| url | https://www.mdpi.com/2076-393X/13/1/89 |
| work_keys_str_mv | AT moraglivingstone protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT kevinaitchison protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT javierpalareaalbaladejo protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT francescociampi protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT clareunderwood protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT antoniapaladino protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT francescachianini protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT garyentrican protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT seanranjanwattegedera protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel AT davidlongbottom protectiveefficacyofdecreasingantigendosesofaichlamydiaabortusisubcellularvaccineagainstovineenzooticabortioninapregnantsheepchallengemodel |