This antibody stains with ORF-73 of human herpesvirus 8 (HHV8). HHV8 is the likely etiological agent of Kaposi sarcoma (KS). HHV8 encodes a latent nuclear antigen (LNA), which is the product of the viral gene ORF 73. LNA is capable of forming a complex with retinoblastoma susceptibility gene product, which may be related to its oncogenic activity.