HERPES-SIMPLEX VIRUS TURNS OFF THE TAP TO EVADE HOST IMMUNITY

MANY viruses have evolved mechanisms to avoid detection by the host im mune system, Herpes simplex virus (HSV) expresses an immediate early p rotein, ICP47, which blocks presentation of viral peptides to MHC clas s I-restricted cells(1). The properties of the newly synthesized class I molecules in HSV-infected cells resemble those of cell lines defici ent in the transporter associated with antigen processing (TAP) in tha t class I molecules are retained in the endoplasmic reticulum(1,2), an d the heavy chain and beta(2)-microglubulin subunits dissociate in det ergent extracts but the complex can be stabilized by peptides(1). We s how here that ICP47 binds to TAP and prevents peptide translocation in to the endoplasmic reticulum.