Group B Streptococcus alpha-like surface protein (Alp)

Group B Streptococcus alpha-like surface proteins are a family of immunogenic, cell wall-anchored proteins found on the surface of Streptococcus agalactiae (Group B Streptococcus, GBS). The canonical members include Alpha C, Rib, Alp1 (epsilon), Alp2, Alp3, and Alp4. They are structurally mosaic and characterized by an N-terminal domain, a repeat region (number of repeats varies between strains and proteins), and a C-terminal domain with an LPXTG sortase-anchoring motif. Alpha-like proteins mediate bacterial adherence to human epithelial cells and contribute to GBS virulence by supporting immune evasion and colonization. Several proteins in the Alp family, particularly Alpha C and Rib, have been evaluated as antigens for GBS vaccine development, as these proteins can elicit protective immunity. No small-molecule drugs are known to target these proteins directly; however, extensive research is ongoing to develop vaccines that include one or more Alp proteins as immunogens to prevent GBS disease, especially in newborns and pregnant women[3][5][8].

Other names

Alpha-like proteinAlp familyAlpha C protein (αC)Rib proteinEpsilon protein (Alp1)Alp2Alp3Alp4C alpha proteinC beta protein

Elicitation of anti-bacterial immunity through vaccination; generally act as vaccine antigens inducing opsonophagocytic antibody responses[3][8]