NIAB scientists working on next generation vaccine against ‘Leptospirosis’

National Institute of Animal Biotechnology (NIAB) scientific team, led by Syed Faisal, is focused on developing the next generation vaccine against this important zoonotic infection.
| Photo Credit: The Hindu Graphics | Subyendu Ganguly

Scientists at the National Institute of Animal Biotechnology (NIAB) are working on the next generation vaccine against ‘Leptospirosis’ — a serious disease affecting both animals and people — caused by a bacteria called ‘Leptospira’, which has over 300 different types of strains. This zoonotic (affecting humans and animals) disease remains a public health concern as it has become more of a threat having escalated prevalence due to the impacts of climate change and global warming.

Why effectiveness of antibiotics might become less?

One million cases of human leptospirosis are reported every year resulting in an estimated 60,000 deaths. Despite the availability of a good number of antibiotics, their effectiveness becomes less when the bacteria infiltrates vital organs causing damage, often due to delayed diagnosis, said scientists of the Institute, under the Department of Biotechnology.

While vaccination is a cost-effective and secure preventive measure to combat this disease, the current killed vaccine only provides short-term immunity specific to certain strains of the zoonotic disease and fails to prevent bacterial shedding through urine.

Vaccines

At present, there’s a vaccine for animals only but it doesn’t protect against all strains of these bacteria and there is no vaccine for humans. The existing vaccines, despite inducing robust cross-protection, do not provide sterilizing immunity or a long-lasting protective response, they said.

NIAB team focused on next gen vaccine

The NIAB scientific team led by Syed Faisal focused on developing the next generation vaccine against this important zoonotic infection against multiple strains, have already characterized a Lipopolysaccharide (LPS) which is one the most important protective antigen and defines the strains specificity, said the Institute Director G. Taru Sharma.

The team has also demonstrated that the initial immune response against LPS may decide whether the host will develop mild infection or succumb to severe infection associated with multi-organ dysfunction. This work has further highlighted that a component of LPS, called Lipid A, is less toxic, can boost the immune response and make vaccines more effective, a significant step in developing a new type of vaccine, she said.

Various antigens, such as Leptospira immunoglobulin-like proteins called ‘LigA and LigB’, have been identified as potential subunit vaccine candidates, these antigens require potent adjuvants for effectiveness. Experiments conducted on mice and hamsters showed these proteins combined with alum and Leptospira Lipid A as adjuvant exhibited significantly higher levels of cellular immune responses and provided sterilizing immunity against Leptospirosis.

“Overall, this research study, supported by Department of Science & Technology (DST) sheds light on the adjuvant properties of Leptospira Lipid A and offers promising avenues for developing LPS-based vaccines against this devastating zoonotic disease. The potent adjuvant activates the innate immune system enhancing a sustained, antigen-specific protective immune response,” said Dr. Faisal. The work has been published in ‘Open Biology and Vaccines’, an international Journal of repute.