The cervical tumor-associated antigen (ICP-10/AG-4) is encoded by the transforming region of the genome of herpes simplex virus type 2.

BglII fragment C mapping between 0.416 and 0.580 map units (mu) on the herpes simplex virus type 2 (HSV-2) genome was used for in vitro translation to identify proteins encoded on this fragment. RNA homologous to the BglII C fragment directs the synthesis of three proteins with approximate molecular weights of 144,000, 52,000 and 27,000. The 27,000 dalton protein is encoded by sequences within the EcoRI/HindIII AE fragment (0.419-0.525 mu) that overlap the immortalizing sequences within BglII C. The 144,000 (144K) and 52,000 dalton proteins are encoded by sequences within the BamHI "e" fragment of HSV-2 DNA (0.535-0.585 mu). The 144K protein is the only species translated in vitro from mRNA hybrid-selected from cells arrested in the "early" (beta) phase of viral protein synthesis. It is precipitated by anti-ICP-10 serum and by monoclonal antibody 48S (previously shown to precipitate the HSV-induced ribonucleotide reductase). The 48S antibody competes with the anti-ICP-10 serum for the 144K protein. Furthermore the in vitro translated 144K protein is structurally similar to ICP-10, an HSV-2-infected cell protein that is antigenically identical to AG-4, the cervical tumor-associated antigen.