Polysaccharide-specific B cell responses to vaccination in humans

Area of Science:

• Immunology
• Vaccinology
• Microbiology

Background:

• Vaccines targeting capsular polysaccharides of *N. meningitidis*, *S. pneumoniae*, and *H. influenzae* type b have decreased disease incidence.
• While antibody responses are known, the underlying B cell populations (plasma cells and memory B cells) are less characterized.

Purpose of the Study:

• To summarize plasma cell (PC) and memory B cell (BMEM) responses after polysaccharide and conjugate vaccination.
• To compare these responses across different vaccine types and age groups.

Main Methods:

• Review and synthesis of existing studies on B cell responses to polysaccharide and conjugate vaccines.
• Analysis of data from various age groups, including infants and older individuals.

Main Results:

• Infant primary PC and BMEM responses to conjugate vaccines are lower than in older groups but increase substantially after booster doses.
• PC kinetics are similar across vaccine types and ages, while BMEM responses differ between plain polysaccharide and conjugate vaccines.
• A correlation between early BMEM responses and sustained antibody levels is suggested but not fully elucidated.

Conclusions:

• Booster doses are crucial for enhancing infant B cell responses to polysaccharide-conjugate vaccines.
• Understanding B cell subset induction mechanisms is key to improving vaccine-induced protective immunity.