Enhancing the efficacy and safety of bovine leptospiral vaccines

Nicholas EvansDr Nicholas Evans
Senior Lecturer
Dept of Infection Biology, University of Liverpool (UK)

Collaborators:

Dr Renate Lamprecht, Afrigen Biologics (South Africa)
Miss Intan Noor Aina Kamaruzaman, Faculty of Veterinary Medicine, Universiti Malaysia Kelantan (Malaysia)
Prof Jeremy Derrick, Division of Infection, Immunity & Respiratory Medicine, University of Manchester (UK)
Dr Stuart Carter, Dept of Infection Biology, University of Liverpool (UK)

Summary

Leptospirosis is a worldwide, severe infectious disease affecting several different species including man and ruminants, particularly in LMIC countries. Globally, cattle are the most severely afflicted in terms of numbers, resulting in severe economic losses, food security impact and substantial antimicrobial use, as well as increased zoonotic spread. Bovine leptospirosis (BL) vaccines are available although there are several constraints inhibiting use in LMIC countries where most of the disease burden is present. Current BL vaccines have a limited range of specificity, only last for a short duration and require cold chain transport and storage which is problematic in many tropical, frequently LMIC, regions with substantial disease burden. 

Bacterial outer membrane proteins (OMPs) are considered an important target to provide cross-protective and long lasting immunity against a range of Leptospira species and serovars. Immune evasion by spirochetes (such as leptospires) is considered to utilise adhesion of host molecules to the bacterial cell surface. Recent research, mutating OMPs to prevent binding to host molecules has increased immune efficacy of OMP vaccines for bacteria. We have identified several OMP amino acids key for adhesion to the host for a thermostable leptospire OMP which already has demonstrated some protective efficacy. Here, through mutating OMP proteins we aim to develop a novel thermostable vaccine with broad Leptospira specificity and enhanced efficacy and safety. Vaccines are considered key mechanisms to reduce AMR. Making vaccines more broadly protective, easily accessible and financially affordable can only increase uptake globally, especially in LMIC countries, therefore decreasing antibiotic use and AMR.