CD46 - Clinical Significance

Clinical Significance

The encoded protein can act as a receptor for the Edmonston strain of measles virus, human herpesvirus-6 (HHV-6), and type IV pili of pathogenic Neisseria.

The extracellular region of CD46 contains four short consensus repeats (SCR) of about 60 amino acids that fold into a compact beta-barrel domain surrounded by flexible loops. As has been demonstrated for CD46 with other ligands, the CD46 protein structure is believed to linearize upon binding HHV-6. While their precise interaction has not yet been determined, the second and third SCR domains have been demonstrated to be required for HHV-6 receptor binding and cellular entry. The heterotetramer gH/gL/gQ1/gQ2 complex of HHV-6 has been identified as a CD46 ligand.

Established medulloblastoma (a malignant brain tumor common in childhood) specimens express CD46, and that medulloblastoma specimens removed from patients had a high level of CD46 expression. Therefore a vaccine made of the Edmonston strain of measles virus could treat the medulloblastoma. Such a vaccine has already been tested in a number of trials involving other tumor types which have a high expression of CD46, including one type of adult brain tumor.