The host immune regulator factor H interacts via two contact sites with the PspC protein of Streptococcus pneumoniae and mediates adhesion to host epithelial cells.

Pneumococcal surface protein C (PspC) of Streptococcus pneumoniae is a key virulence factor that mediates adhesion to host cells and immune evasion of the host complement. PspC binds the host immune and complement regulator factor H, which is composed of 20 short consensus repeats (SCR). This interaction contributes to pneumococcal virulence.