Infected cell protein 4 (ICP4) (ICP4)

Infected cell protein 4 (ICP4) is a major immediate-early protein of Herpes Simplex Virus type 2 (HSV-2) that serves as a master regulator of the viral life cycle (UniProt P06484). It is a large, homodimeric DNA-binding protein that functions as a transcriptional activator for early and late viral genes while acting as a repressor for its own expression and other immediate-early genes (PubMed: 24501061). Because ICP4 is essential for viral replication and is highly expressed during the early stages of infection, it is a primary target for immunotherapy and therapeutic vaccines (PubMed: 28137889). For instance, the vaccine candidate GEN-003 utilizes a recombinant fragment of ICP4 alongside glycoprotein D2 to stimulate both T-cell and B-cell immune responses (Genocea Biosciences). By targeting ICP4, these therapies aim to control viral reactivation, thereby reducing viral shedding and the frequency of genital herpes outbreaks in infected patients.

Other names

RS1Immediate-early protein 1IE175Regulatory protein ICP4HSV-2 ICP4

Induction of T-cell and B-cell immune responses to inhibit viral replication and reduce viral shedding.