Research aims to improve enzootic abortion vaccines
A vaccine being developed against ovine enzootic abortion by scientists at the Moredun Research Institute has shown promising results in laboratory trials, being able to protect against abortion caused by Chlamydia abortus without the risk of causing infection in the animal. The results of the study are published in Vaccines.
Ovine enzootic abortion is a major cause of reproductive loss in small ruminants worldwide. 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.
Researchers investigated the efficacy of two subcellular vaccines based on detergent-extracted whole organism C. abortus outer membrane preparations in pregnant ewes experimentally challenged with C. abortus, with a view to developing a safer and more stable alternative to the commercial live vaccines.
Dr David Longbottom, leading the study from Moredun said, “We are very encouraged by the results we have seen with the new vaccine as it is able to induce effective immune responses in sheep protecting against abortion and because the new vaccine is not live, it will not cause infection in vaccinated animals, giving additional safety benefits.”
The team are currently looking to further optimise the vaccine formulation to make additional improvements. They say that to improve commercial viability, future studies should optimise the antigen dose and number of inoculations required.
Article: Livingstone, M., Wattegedera, S. R., Palarea-Albaladejo, J., Aitchison, K., Corbett, C., Sait, M., Wilson, K., Chianini, F., Rocchi, M. S., Wheelhouse, N., Entrican, G., Longbottom, D. (2021). Efficacy of Two Chlamydia abortus Subcellular Vaccines in a Pregnant Ewe Challenge Model for Ovine Enzootic Abortion. Vaccines, 9(8), 898, doi: 10.3390/vaccines9080898
[SOURCE: Moredun Research Institute]