Recombinant fusion protein LipL41-OmpL1 as a Potential Candidate for a Cost-effective Vaccine against Leptospirosis.

Leptospirosis represents a significant threat to the health of both humans and animals. It is a disease caused by pathogenic Leptospira. The early detection of pathogenic Leptospira is an effective method for preventing a multitude of potential complications. The protected outer membrane protein (OMP) of pathogenic Leptospira, LipL41-OmpL1, was inserted into E. coli bacteria using different software for the amino acid sequence of OmpL1 and LipL41. This was done to design a recombinant fusion protein, which was then expressed to investigate immunogenicity. The selected genes were propagated and cloned as a fusion in a PET32a+ plasmid vector and expressed by Escherichia coli strain S (DE3) via a heat shock method. The evaluation was conducted using the BALB/c mouse as the laboratory animal model. The recombinant LipL41-OmpL1 protein was confirmed using the urea purification method and western blot, and its immunogenicity was evaluated by measuring the high humoral immune stimulation and antibody secretion in BALB/c mice by the ELISA method. The findings demonstrated that the animals that received both the OmpL1 and LipL41 proteins exhibited 85% immunogenicity, whereas the control group that did not receive the fusion protein demonstrated only 25% immunogenicity (P<0.001). Moreover, no evidence of infection was identified in recipients of the OmpL1-LipL41 fusion protein, indicating that this protein is safe for use. The protective effects of immunization with OmpL1 and LipL41 were synergistic, as no significant levels of protection were observed in animals immunized with OmpL1 or LipL41 alone. In conclusion, this study underscores the potential of a recombinant OmpL1 and LipL41 fusion protein as a promising avenue for research in the development of vaccines and ELISA diagnostic kits for the prevention and rapid diagnosis of leptospirosis.