AIDS Res Hum Retroviruses
May 1996
A highly conserved gp41 epitope (amino acid sequence ELDKWA) has been described to elicit antibodies neutralizing a broad variety of HIV-1 strains. We analyzed the antibody reactivity of HIV-1-infected individuals from Argentina and Sweden to overlapping synthetic peptides covering aa647-684 of HIV-1 MN gp41. An immunodominant antigenic determinant was discovered in the C-terminal region adjacent to the ELDKWA sequence.
View Article and Find Full Text PDFThe complete herpes simplex virus type 2 envelope glycoprotein G was represented by overlapping synthetic peptides. Herpes simplex virus type 2-specific human seroreactivities were mainly seen against three peptides, peptides G2-64, G2-69, and G2-70, located in the C-terminal part of glycoprotein G. This is, interestingly, a region which has strong homology between herpes simplex virus types 1 and 2.
View Article and Find Full Text PDFActa Obstet Gynecol Scand
April 1996
Background: Parvovirus infection during pregnancy has been reported to be associated with spontaneous abortion and fetal loss.
Objective: To show the incidence of antibodies against Parvovirus B19 early in pregnancy and sero-reactivities during and after pregnancy.
Study Design: In a prospective study during a non-epidemic period, 457 women admitted to an antenatal care center were included.
Hybrids of the core protein of hepatitis B virus (HBcAg) have been designed which carry N-terminal insertions of B- and T-cell epitopes of HIV-1 an immunodominant B-epitope from gp41, a T-cell epitope from p34 pol, and a cluster of B- and T-cell epitopes from p17 gag. The hybrids have been synthesized using two expression systems-one based on the thermoinducible PR promoter of bacteriophage lambda and the other one based on phi 10 promoter of bacteriophage T7 with 3-5% and 7-14% yields, respectively. The hybrids have dual HBV and HIV-1 immunospecificity and are assembled into particles similar to those formed by the protein carrier HBcAg.
View Article and Find Full Text PDFA poliovirus-binding inhibition test (PoBI test) was established for the quantitative determination of antibodies to polioviruses and was evaluated in comparison with the conventional neutralization test (NT). The first step of the PoBI test is an incubation of serial dilutions of test samples with inactivated poliovirus followed by the detection of free viral epitopes by a double antibody sandwich enzyme-linked immunosorbent assay with type-specific capture polyclonal antisera and type-specific neutralizing monoclonal indicator antibodies. A comparison of the PoBI test with the conventional NT for antibodies to all three types in 100 human serum samples showed excellent correlations (r > 0.
View Article and Find Full Text PDFJ Acquir Immune Defic Syndr Hum Retrovirol
August 1995
Evidence has been presented for the involvement of various cytokines, including interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha, in the pathogenesis of human immunodeficiency virus (HIV) infection. Since measured plasma levels may poorly reflect in vivo production of cytokines, we adopted in situ hybridization with cDNA oligonucleotide probes to enumerate blood mononuclear cells (MNCs) expressing mRNA for IL-6, IL-10, TNF-alpha, and perforin. The HIV-infected patients had elevated levels of MNCs expressing mRNA for all four cytokines compared to healthy controls.
View Article and Find Full Text PDFBackground: The contribution of cytomegalovirus (CMV) to progressive HIV infection is still controversial.
Objective: The occurrence of CMV DNA in the plasma of patients with advanced HIV infection was studied in relation to the development of clinical disease.
Study Design: Plasma samples were collected every 2 weeks for 6 months.
Activation of the anti-human immunodeficiency virus (HIV) compound 3'-azido-3'-deoxythymidine (AZT) is dependent on its 5'-phosphorylation by cellular nucleoside and nucleotide kinases. Azidothymidine 5'-triphosphate (AZTTP) is considered to be the metabolite responsible for both the anti-HIV effect of AZT, via inhibition of reverse transcriptase, and cytoxicity by interference with cellular DNA polymerases. During the characterization of AZT metabolism in cultured human T-lymphoblastoid CEM cells, a spontaneously occurring variant cell line, CEM/Ag-1, was found that showed approximately 10-fold resistance to AZT growth inhibition as compared to wild type (wt) cells (EC50 = 2 mM as compared to 350 microM for wt cells).
View Article and Find Full Text PDFBackground: Certain antigens of the HIV-1, e.g., gp120-envelop proteins, can be expressed on the membrane of HIV-infected cells.
View Article and Find Full Text PDFMolecular and cellular requirements for antigen-specific isotype switch of human B cells have been investigated by mimicking signaling occurring in germinal centers. Peripheral blood mononuclear cells from healthy seronegative blood donors were first primary immunized in vitro, using a synthetic immunogen containing both a T and B cell epitope, which generated specific IgM-secreting B cells. We used the apex of the V3 loop of gp120 as B cell epitope linked to a promiscuous T helper epitope from tetanus toxin.
View Article and Find Full Text PDFGenes encoding the immunoglobulin variable regions of a human anti-HIV-1 IgG1 kappa monoclonal antibody were rescued from a hybridoma, derived from a sero-negative donor, using PCR cloning and expression in Escherichia coli. The ELISA binding results obtained from the expressed Fab fragment confirmed the anti-V3 loop specificity for HIV-1 (LAI) of the original antibody. In addition, an amino acid sequence derived from the second complementarity determining region (CDRH2) of the heavy chain was found to be very similar to the catalytic motif of CD26, a T-cell activation antigen.
View Article and Find Full Text PDFAIDS Res Hum Retroviruses
December 1994
The sensitivity of primary isolates of HIV-2 to the antiretroviral drugs 3'-azido-3'-deoxythymidine (AZT), 2',3'-dideoxyinosine (ddI), and 3'-fluoro-3'-deoxythymidine (FLT) was measured in vitro in PBMCs and compared to that of primary isolates of HIV-1. HIV-2 isolates showed a similar sensitivity to the drugs compared to HIV-1 isolates. Both the relative and the absolute potencies of the three drugs were similar for inhibition of HIV-1 or HIV-2 replication.
View Article and Find Full Text PDFTetanus toxoid-specific T cells have been generated from human splenic lymphocytes by an initial 6-day stimulation period with antigen, followed by a proliferation period with recombinant IL-2 and human feeder cells. Proliferating T cells were subsequently cloned by limiting dilution. A human T-cell clone that was functionally characterized showed: (i) a specific proliferative response to tetanus toxoid in the presence of autologous Epstein-Barr virus (EBV)-transformed lymphoblastoid cells; (ii) a phenotype characteristic for the helper/inducer CD4+/CD8-/CD450R0+ T cells, and (iii) a lymphokine profile, as determined by mRNA analysis, representative of Th0-like human CD4+ T helper cells.
View Article and Find Full Text PDFPeptides were synthesized which combined HIV-1 B-epitopes from gp41, p34pol and heterologous T-cell epitopes from hepatitis B virus (HBV) core or tetanus toxoid. Mixtures of these composite peptides and peptides representing single HIV-1 B-epitopes were used to immunize rabbits in an adjuvant-free immunization regimen. Fusion to T-cell epitopes made the HIV-1 B-epitopes immunogenic and high titers of anti-HIV-1 antibodies were reached.
View Article and Find Full Text PDFThe interaction between the HIV envelope glycoprotein gp120 and the CD4 molecule is probably the most important primary event determining HIV infection. Reactivity with the native viral envelope has been difficult to measure due to the lack of gp120 ligand purified directly from primary virus cultures. We have developed an ELISA, utilizing Galanthus nivalis agglutinin (GNA) which selectively binds native HIV envelope gp120 in culture medium.
View Article and Find Full Text PDFJ Acquir Immune Defic Syndr (1988)
September 1994
J Acquir Immune Defic Syndr (1988)
September 1994
Mouse monoclonal antibodies with high human immunodeficiency virus type 1 (HIV-1) neutralizing titers were used for passive immunotherapy of eleven late-state HIV-infected patients. In five patients the serum level of the core protein p24 decreased, while in five cases it remained unchanged. The level of viral RNA in plasma as measured by quantitative polymerase chain reaction (PCR) decreased in four cases, was stable in another four, and increased in three cases.
View Article and Find Full Text PDFThe mechanisms by which CD4+ T cells are eliminated during HIV infection are poorly understood. We have previously shown that HIV infected cell lines activate and fix C3 via the alternative complement pathway (ACP). In the present study we examined the ability of blood lymphocytes from 40 HIV+ individuals to fix C3.
View Article and Find Full Text PDFHepatitis B virus (HBV) core antigen (HBcAg) particles purified from Escherichia coli were probed in a competition enzyme immunoassay (EIA) with a panel of 16 murine monoclonal antibodies (MAbs) directed to different forms of core protein. The linear binding sites of the MAbs were mapped by combination of solid-phase and competition EIA using synthetic peptides covering the complete sequence of HBV core protein. Relative accessibilities of the linear binding sites at the HBcAg surface were investigated by comparing reactivities in solution of the MAbs to (i) two genetic variants of particulate HBcAg, (ii) denatured core protein, and (iii) synthetic peptides mimicking the appropriate linear binding sites.
View Article and Find Full Text PDFThe HIV-1 envelope protein contains several regions with amino acid homology to HLA class I and class II molecules. We evaluated possible changes in antibody responses to those regions during vaccination with rgp 160 produced in a baculovirus system. Forty asymptomatic HIV-infected patients with CD4 cell counts above 400 were vaccinated with rgp 160.
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