Streptococcus pneumoniae Type 5 Polysaccharide

Streptococcus pneumoniae Type 5 Polysaccharide is a specific serotype of the capsular polysaccharide (CPS) produced by Streptococcus pneumoniae serotype 5. Like other pneumococcal CPS serotypes, it forms a protective layer around the bacterium, shielding it from phagocytosis by host immune cells. This allows Streptococcus pneumoniae serotype 5 to colonize the upper respiratory tract and cause invasive infections, such as pneumonia, bacteremia, and meningitis. Streptococcus pneumoniae serotype 5 is among the most common serotypes associated with invasive pneumococcal disease worldwide, particularly in children and older adults. The Type 5 Polysaccharide is immunogenic, and exposure to the bacterium (or vaccination with a vaccine containing this polysaccharide) induces the production of serotype-specific antibodies. These antibodies bind to the Type 5 Polysaccharide, opsonizing the bacterium (marking it for phagocytosis) and enabling the immune system to clear the infection. This serotype is included in multivalent pneumococcal conjugate vaccines (e.g., PCV13, PCV20), which protect against the most clinically relevant pneumococcal serotypes, including Type 5.