The Epstein-Barr virus (EBV), also called human herpesvirus 4 (HHV-4), is one of eight known viruses in the herpes family, and is one of the most common viruses in humans. EBV infects B cells of the immune system and epithelial cells. The EBV-induced early antigens (Ea) are among several antigen complexes that have been identified in EBV-infected cells. The Ea complex is composed of diffuse (Ea-D) and restricted (Ea-R) components.