Scientists at the National Institute of Animal Biotechnology (NIAB) are making strides in developing a next-generation vaccine against leptospirosis, a severe zoonotic disease impacting both human and animal populations. Leptospirosis, caused by Leptospira bacteria, poses a significant public health challenge, with an estimated one million human cases reported annually, resulting in approximately 60,000 deaths.
Addressing Limitations of Current Vaccines
Existing killed vaccines offer only short-term immunity and are specific to certain strains, failing to prevent bacterial shedding. While animal vaccines exist, they do not protect against all strains, and no human vaccine is currently available. These current vaccines, despite inducing cross-protection, lack sterilizing immunity and a long-lasting protective response.
Targeting Lipopolysaccharide (LPS) for Enhanced Immunity
The NIAB team, led by Syed Faisal, is focusing on Lipopolysaccharide (LPS), a crucial protective antigen that defines strain specificity. Research indicates that the initial immune response against LPS determines the severity of the infection. G. Taru Sharma, Director of NIAB, noted that Lipid A, a component of LPS, is less toxic and can enhance the immune response, making vaccines more effective.
Promising Results with LigA and LigB Proteins
Experiments in mice and hamsters have shown that leptospira immunoglobulin-like proteins LigA and LigB, combined with alum and Leptospira Lipid A as an adjuvant, significantly increased cellular immune responses and provided sterilizing immunity against leptospirosis. Dr. Faisal stated that this research, supported by the Department of Science & Technology (DST), highlights the adjuvant properties of Leptospira Lipid A, offering promising avenues for developing LPS-based vaccines. The potent adjuvant activates the innate immune system, enhancing a sustained, antigen-specific protective immune response.
