Group B Streptococcus Alpha-Like Protein Family (Alp family)

The Group B Streptococcus (GBS) alpha-like protein (Alp) family is a group of immunogenic, repeat-containing surface proteins expressed by most GBS isolates. These proteins play key roles in bacterial adhesion, immune evasion, and are major targets for vaccine development due to their strong immunogenicity and prevalence among clinical isolates. The Alp family includes at least six characterized members: Alpha C protein (Cα), Rib, Alp1 (also called epsilon), Alp2, Alp3, and Alp4. Each GBS strain typically expresses one member of the family. They function primarily as adhesins, facilitating attachment to host cells, and contribute significantly to colonization, persistence, and invasion during infection. They also elicit strong immune responses, making them prime candidates for inclusion in multivalent vaccines aimed at preventing neonatal disease.

Other names

Alpha-like protein familyAlpha C proteinCαRibAlp1EpsilonAlp2Alp3Alp4

Antibody-mediated opsonophagocytic killing