Mapping and serodiagnostic application of a dominant epitope within the human herpesvirus 8 ORF 65-encoded protein.

Eighteen of 20 Kaposi's sarcoma (KS)+HIV+ patients showed seroreactivity with a 14-mer peptide incorporating the deduced 8-mer epitope. The epitope was mapped with overlapping peptides and substitution analysis. Substitution analogs of the 14-mer peptide revealed that amino acids P165 and K169 are most important for antibody recognition. Reactivity was also seen in 4 of 20 KS-HIV+ patients, but in none of the KS-HIV- patients. In a competition assay, the homologous Epstein-Barr virus 14-mer peptide (QPHDTAPRGARKKQ) derived from BFBR3-encoded protein did not interfere with the assay, suggesting that the HHV8 14-mer is specific for HHV8.