A groundbreaking study involving Kenyan sex workers has shed light on the immune response to gonorrhoea, opening the way to more effective vaccines.
The study was conducted by scientists from the Universities of Manchester and Oxford in collaboration with the KEMRI/Wellcome Trust Unity in Kenya. The results of the study are published in the journal Nature Communications and were funded by the Wellcome Trust.
The findings come amid recent reports that gonorrhoea, a sexually transmitted disease, is becoming increasingly resistant to antibiotics and may become untreatable in the future.
People infected with gonorrhea may experience pain or burning, but if left untreated, they can develop more serious problems, including infertility, systemic infection, and an increased risk of HIV/AIDS.
Currently, there are strains with multiple drug resistance. Neisseria gonorrhoeae (Ng) bacteria – which causes gonorrhea, making many antibiotics ineffective as first-line treatment.
This bacterium has a number of mechanisms that weaken immune responses, meaning it does not have enough immunological “memory” to fight subsequent infections.
Efforts to develop a vaccine against gonorrhea have largely failed; however, a 2017 study found that vaccination against a related bacterium Neisseria meningitidis (Nm) led to a decrease in the incidence of gonorrhea.
Although the efficacy of the Nm vaccine against Ng was limited, it provided important clues for the design of an effective Ng vaccine.
Working with a marginalised community of sex workers in coastal Kenya who are at high risk of contracting gonorrhoea, Professor Ed Sanders and his team in Kenya conducted a trial of the Nm vaccine to study their immune responses.
Professor Jeremy Derrick and his team in Manchester then measured the pattern of antibody responses in vaccine recipients and compared them with those infected with gonorrhoea.
To understand the complex antibody responses, a team of scientists from Manchester created a 'microarray' – a library of different components or antigens that could react with the antibodies induced by the Nm vaccine.
Using this powerful technology, complex antibody profiles against different components were determined for each vaccinated or infected person.
Comparison of the profiles revealed a detailed picture of the antibody response to the vaccine and how it differed from responses following infection.
Project leader Professor Chris Tang, from the University of Oxford, said: “This work is an important step towards developing vaccines against Ng as we have a better understanding of what responses occur during partially protective vaccination compared with infection.”
Professor Derrick added: “This research has wide implications for reconsidering the development of vaccines against other bacterial pathogens using these new methods, including those where antimicrobial resistance is a concern.
“We hope that the application of these technologies will enable progress in the creation of vaccines against other pathogens.”
Image: A raw scan of the microarray. Each spot is an antibody that reacts with a specific antigen or protein from the bacterium. Neisseria gonorrhoeae.
Stejskal et al. 2024, “Profiling IgG and IgA antibody responses during vaccination and infection in a high-risk gonorrhoea population,” is published in Nature Communications and available here.