Deciphering the Function of New Gonococcal Vaccine Antigens Using Phenotypic Microarrays

Area of Science:

• Microbiology
• Vaccinology
• Proteomics

Background:

• Cell envelope proteins of Neisseria gonorrhoeae are targets for vaccine development.
• The functions of many gonorrhea vaccine candidates identified through proteomics remain unknown.
• Understanding these functions is crucial for developing effective vaccines against gonorrhea, a prevalent sexually transmitted infection.

Purpose of the Study:

• To probe the functions of six Neisseria gonorrhoeae vaccine candidates (NGO2121, NGO1985, NGO2054, NGO2111, NGO1205, and NGO1344) in cell envelope homeostasis.
• To establish phenotype microarrays as a viable method for studying fastidious bacteria like N. gonorrhoeae.
• To identify promising vaccine candidates based on their functional roles.

Main Methods:

• Utilized phenotype microarrays under 1,056 conditions to assess the function of N. gonorrhoeae vaccine candidates.
• Employed a ΔbamE mutant as a reference for outer membrane integrity.
• Developed optimal growth conditions for N. gonorrhoeae phenotype microarray assays in defined liquid medium.

Main Results:

• Identified 91 conditions with unique effects on the examined mutants.
• Cluster analysis revealed three distinct phenotype groups for the vaccine candidates and a BamE mutant.
• NGO1985 and NGO2121 demonstrated extensive sensitivity phenomes, indicating their potential as vaccine candidates.
• Similar phenotypes were observed in a highly antibiotic-resistant WHO X strain.

Conclusions:

• Phenotype microarrays are effective for investigating the function of hypothetical proteins in fastidious bacteria like N. gonorrhoeae.
• The study provides insights into the roles of vaccine candidates in N. gonorrhoeae membrane permeability and integrity.
• NGO1985 and NGO2121 are identified as the most promising gonorrhea vaccine candidates based on their functional characterization.