Poster Presentation 15th Lorne Infection and Immunity 2025

Development of vaccines against gonococcal disease using the PilVax platform (#315)

Mejo Chiratteparambil Korah 1 2 , Catherine Tsai 1 2 , Thomas Proft 1 2
  1. Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
  2. School of medical sciences, University of Auckland, Auckland, New Zealand

Gonorrhoea is a sexually transmitted disease caused by Neisseria gonorrhoeae, with a high prevalence across the world. There is currently no licenced vaccine against gonorrhoea, but vaccine development is a top priority, particularly with the rise of antimicrobial resistance (AMR). Pilvax is a novel peptide vaccination platform that can trigger systemic and mucosal immune responses. Selected peptides from the Neisseria gonorrhoeae multidrug transporter system E (MtrE) loop 2, Transferrin binding protein A (TbpA) loop 10, a peptidomimetic of lipooligosaccharide (2C7), adhesion complex protein (ACP) and the novel gonococcal antigen NGO2054 have previously raised interest as potential vaccine targets for gonorrhoea. Bioengineering of selected peptides into the M1T1 or M6T6 pilus structure of Group A Streptococcus (GAS) and further expressing the recombinant pili on the surface of the food-grade bacterium Lactococcus lactis offers peptide amplification, stabilisation and enhanced immunogenicity. The selected peptides from gonococci were successfully cloned into the GAS pilus and expression on L. lactis was confirmed by Western blot and flow cytometry. BALB/c mice were immunized intranasally with the modified L. lactis, and antibody responses (serum IgA/IgG and mucosal IgA) were analyzed. In-house generated peptide proteins fused with either thioredoxin or glutathione-S-transferase were mixed with cholera toxin B as control vaccines or used as coating antigens in ELISAs. The splenocyte re-stimulation assay was also employed to determine the impact of PilVax on inducing cellular immune responses. Significant serum titers of peptide-specific immunoglobulin (IgG and IgA) were detected in the vaccinated mice. In the future, serum bactericidal assay (SBA), cell adhesion inhibition assays and a mouse vaginal tract infection model will be employed to test for vaccine efficacy.