The Vlp and Vsp proteins are antigenically distinct proteins, only one vlp or vsp gene is transcriptionally active at any one time. Switching between these genes is a mechanism of host immune response evasion. Genes for both Vlp and Vsp families are on (usually) unnamed linear plasmids in B.hermsii HS1. Belongs to the variable large protein (Vlp) family. Beta subfamily.