Pilus adhesin RrgA (RrgA)

Pilus adhesin RrgA is the primary adhesive protein located at the tip of the type 1 pilus (pilus-1) in Streptococcus pneumoniae. It mediates the initial attachment of the bacterium to host tissues by binding to respiratory epithelial cells, vascular endothelial cells, and extracellular matrix components such as collagen I, fibronectin, and laminin (PMID: 18250390, 20133637). Beyond its role in colonization, RrgA facilitates the crossing of the blood-brain barrier and interacts with host immune cells, including macrophages, through the complement receptor 3 (CR3) to modulate the inflammatory response (PMID: 23269481, 32185835). Due to its critical role in virulence and its high surface exposure, RrgA is a prominent candidate for the development of serotype-independent, protein-based pneumococcal vaccines. Therapeutic strategies targeting RrgA, such as monoclonal antibodies or vaccine-induced immunity, aim to block bacterial adherence and prevent invasive diseases like pneumonia, meningitis, and sepsis (PMID: 33141143, 20660671).

Other names

RrgA proteinPneumococcal pilus-1 adhesinAncillary pilus subunit RrgAStreptococcus pneumoniae RrgA

Inhibition of bacterial adherence to host cells and extracellular matrix components, thereby preventing colonization and invasive disease.