Qualification of a high-throughput luminescence-based Serum Bactericidal Activity assay to assess the functionality...

Area of Science:

• Immunology
• Vaccinology
• Microbiology

Background:

• Shigellosis is a major cause of diarrheal disease, particularly affecting young children and the elderly in low- and middle-income countries (LMICs).
• The increasing incidence of shigellosis and the growing threat of antimicrobial resistance necessitate the development of effective vaccines.
• Currently, no established correlate of protection exists for shigellosis, hindering vaccine evaluation and licensure.

Purpose of the Study:

• To develop and qualify a high-throughput luminescence-based Serum Bactericidal Activity (L-SBA) assay for evaluating Shigella vaccine candidates.
• To establish a reliable method for measuring functional antibody activity against epidemiologically relevant Shigella serotypes.

Main Methods:

• A luminescence-based Serum Bactericidal Activity (L-SBA) assay was developed for high-throughput antibody functionality testing.
• The L-SBA assay was transferred to a Clinical Research Organization (CRO) and qualified for five key Shigella serotypes (S. flexneri 2a, 1b, 3a, 6, and S. sonnei) using pooled human serum.

Main Results:

• The L-SBA assay demonstrated repeatability, intermediate precision, and linearity, confirming its robustness.
• The assay successfully detected serotype-specific Shigella antibody activity, validating its specificity.
• The qualification confirmed the assay's suitability for use across different laboratories.

Conclusions:

• The qualified L-SBA assay is a reliable and reproducible method for assessing functional antibodies against Shigella.
• This assay is suitable for evaluating multicomponent vaccine candidates against shigellosis, supporting vaccine development and licensure.
• The L-SBA assay provides a valuable tool for advancing shigellosis vaccine research and public health efforts.