What is "cryptotope"

A cryptotope is an antigenic site or epitope hidden in protein or virion because it is present on the surface subunits that become buried. Cryptotopes are antigenically active only after dissociation of protein aggregates and virions A cryptotope can also be referred to as a cryptic epitope. Cryptic epitopes or cryptotopes are becoming important for HIV vaccine research as a number of studies have shown that cryptic epitopes can be revealed or exposed when HIV gp120 binds to CD4.