B Cell Response Patients Moa Ppcv23 Ppsv23 Polysaccharide

PPSV23 → polysaccharide vaccine (23 S.pneumoniae serotypes) → not conjugated to protein so they cannot be displayed to T-cell-receptors by MHCII (B cell activation independent of T cells) → T-cell-independent immune response leads to immuen response and moderate antibody production that is effective for most patients

↓

Ineffective for patients x<2 years of age as they have not developed mature T-independent B cell activation