Comparison of the immunoglobulin-G-specific seroreactivity of different recombinant antigens of the human herpesvirus 8

The open reading frames ORF 52, ORF 65, K12, and K8.1 of the human herpesvi rus 8 (HHV8) were expressed as glutathione-S-transferase (GST) fusion prote ins and analysed by Western blotting (WB) and enzyme-linked immunosorbent a ssay (ELISA). The open reading frame (ORF) 65 and K8.1 antigens gave the hi ghest reactivity (71%) in sera from HIV-dependent Kaposi's sarcoma (KS) pat ients. Therefore both antigens appear to be essential for HHV8 diagnostics, whereas ORF K12 and ORF 52 were of minor importance. Using polymerase chai n reaction (PCR) out of the peripheral blood of these KS patients, 48% were detected as positive. By testing an N-terminal-deleted construct (amino ac id 80-171) of ORF 65, we could show that the N-terminal region of this prot ein is essential to mediate full immunogenic reactivity. By analysing diffe rent deletion mutants of ORF K8.1, the major epitope was found to be locate d between aa 29 and 101. The prevalence of antibodies directed against the different antigens was determined for healthy blood donors to be 3-6%. The different antibody patterns obtained in HIV-patients with and without KS su pport the hypothesis that different antibody profiles develop during the co urse of KS. (C) 1999 Academic Press.