Reactivities of Human Sera with Human Herpesvirus-8-Infected BCBL-1 Cells and Identification of HHV-8-Specific Proteins and Glycoproteins and the Encoding cDNAs

Abstract

The reactivates of human sera with uninduced and phorbol ester (TPA)-induced human herpesvirus-8 (HHV-8)-infected BCBL-1 cells were examined by immunofluorescence assay (IFA) and by radioimmunoprecipitation reactions (RIP). The seroprevalence of HHV-8 infections is low in the United States general population and only low levels of HHV-8 antibodies were detected in the seropositive sera. In contrast, high levels of antibodies against HHV-8 lytic and latent antigens were detected by IFA in the sera from HIV+ Kaposi's sarcoma (KS)-positive individuals. These sera recognized several proteins and glycoproteins from BCBL-1 cells in RIP reactions. Two types of antibody responses were detected in the sera from HIV+ KS- homosexual men. In majority of the sera with and without detectable HHV-8 DNA in the peripheral blood mononuclear cells (PBMC), significantly low levels of HHV-8 antibodies were detected by IFA. These sera recognized only a subset of HHV-8 proteins and glycoproteins in RIP reactions. In contrast, in a subgroup of sera from HIV+ KS- homosexual men, higher levels of IFA antibodies against HHV-8 lytic and latent antigens were detected. These sera also recognized several viral proteins and glycoproteins in RIP reactions. These results suggest that antibody response profiles to HHV-8 infection vary significantly and serologic assays to detect antibody responses to a panel of both lytic and latent antibodies may be required for maximum sensitivity. Screening of a cDNA library from TPA-induced BCBL-1 cells with an HIV+ KS+ serum identified cDNAs encoding 12 HHV-8 proteins. Further characterization of these HHV-8 proteins would define the HHV-8 antigens useful for seroepidemiological studies and in discriminating lytic, latent, past, and/or reactivation infections.

Comparative Evaluation of Three Serological Methods for Detection of Human Herpesvirus 8-Specific Antibodies in Canadian Allogeneic Stem Cell Transplant Recipients

“…Previous studies have shown that the detection of HHV-8 antibodies for lytic proteins was generally more sensitive than the detection of HHV-8 DNA in peripheral blood mononuclear cells for the assessment of HHV-8 infections in HIVinfected patients with KS (13,33). By contrast, some authors (15,28) have found HHV-8 DNA by PCR in bone marrow stromal cells obtained from patients with multiple myeloma in whom HHV-8-specific antibodies had not been detected.…”

Human herpesvirus 8 (HHV-8) and the etiopathogenesis of Kaposi's sarcoma

“…More recently, using uninduced and TPA-induced BCBL-1 cells 35 , IFA antibody titers to HHV-8 were found to be much higher in HIVinfected Los Angeles patients with KS than in those HIV-infected without KS; furthermore, antibody positivity rate was 8% in healthy individuals, 56% in HIV-positive homosexual men, and 12% in age-matched HIV-negative controls 36 .…”

Kaposi's Sarcoma-Associated Herpesvirus Open Reading Frame 50/Rta Protein Activates the Entire Viral Lytic Cycle in the HH-B2 Primary Effusion Lymphoma Cell Line

“…Sera of patients with KS contain high titers of antibodies to both latent and lytic cycle viral products (1,8,9,15,17,22,27,35). Although the majority of tumor cells are latently infected, some spindle cells and monocytic cells in the KS lesions express lytic cycle products, including chemokines and proinflammatory cytokines encoded by KSHV (4,24,25,36,37,41).…”