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W Rönspeck

Publications and source records attributed to W Rönspeck.

8 recordsLinked to original sources
PubMed1998

Peptide design by artificial neural networks and computer-based evolutionary search.

A technique for systematic peptide variation by a combination of rational and evolutionary approaches is presented. The design scheme consists of five consecutive steps: (i) identification of a "seed peptide" with a desired activity, (ii) generation of variants selected from a physicochemical space around the seed peptide, (iii) synthesis and testing of this biased library, (iv) modeling of a quantitative sequence-activity relationship by an artificial neural network, and (v) de novo design by a computer-based evolutionary search in sequence space using the trained neural network as the fitness function. This strategy was successfully applied to the identification of novel peptides that fully prevent the positive chronotropic effect of anti-beta1-adrenoreceptor autoantibodies from the serum of patients with dilated cardiomyopathy. The seed peptide, comprising 10 residues, was derived by epitope mapping from an extracellular loop of human beta1-adrenoreceptor. A set of 90 peptides was synthesized and tested to provide training data for neural network development. De novo design revealed peptides with desired activities that do not match the seed peptide sequence. These results demonstrate that computer-based evolutionary searches can generate novel peptides with substantial biological activity.

Amino Acid Sequence↗
PubMed1993

Two-colour combination enzyme-linked immunosorbent assay for the simultaneous detection of HBV and HIV infection.

To reduce the cost, time and waste in screening for HIV and HBV infections a combined assay for HIV-1 and -2 antibodies and HBsAg has been developed. Monoclonal anti-HBs antibodies were co-immobilized with synthetic peptides representing immunodominant regions of HIV-1 and -2. The presence of anti-HIV antibodies in the samples was detected with alkaline phosphatase-labelled anti-human IgG and of HBsAg with horseradish peroxidase-labelled monoclonal anti-HBs antibodies by a sequential substrate reaction. In this assay, HBsAg was detectable in a concentration range between 0.25 and 0.30 U/ml and the results were available within 3 h. The specificity, tested on 5000 serum samples from blood donors after confirmation, was 99.8% for HBsAg and 99.5% for anti-HIV antibody detection. All serum samples taken from 600 HIV-1- and 115 HIV-2-infected individuals were correctly classified as reactive. The two-colour HBsAg-anti-HIV-1/-2 combination ELISA meets all the requirements of single parameter assays with regard to precision, stability and robustness.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Expression of nef, vpu, CA and CD4 during the infection of lymphoid and monocytic cell lines with HIV-1.

The expression of the capsid antigen (CA) and the two regulatory proteins nef and vpu as well as the CD4 cell surface receptor was followed in HIV-infected lymphoid and promonocytic cells. In the lytic phase of infection all three viral proteins were expressed; production of these proteins coincided with the increase of CA antigen and infectious virus in culture supernatants and with prominent cytopathic effects. After selection of persistently infected cells, the number of lymphoid cells expressing detectable levels of nef decreased to zero; the number of cells positive for CA ranged between 40 to 70%. In chronically infected promonocytic cells nef and vpu expression was reduced to undetectable levels, whereas most of the cells accumulated CA intracellularly. Infectious cell free virus and CA in the supernatant of promonocytic cells had low titers. CD4 surface expression declined in all cell lines investigated before cell free virus was detectable.

Amino Acid Sequence↗
PubMed1992

Prognostic B-cell epitopes on the flagellar protein of Borrelia burgdorferi.

Overlapping decapeptides based on the flagellin sequence of Borrelia burgdorferi B31 (G. S. Gassmann, M. Kramer, U. B. Göbel, and R. Wallich, Nucleic Acids Res. 17:3590, 1989) were used to identify immunologically reactive regions of flagellin. Five serum specimens from patients with late manifestations of Lyme disease and borrelia-specific monoclonal antibody H9724 reacted with an epitope in the central region of the flagellar protein (amino acids 205 to 226), which is heterologous to the amino acid sequences of other bacterial flagellins. This epitope was not recognized by human sera with antibodies to Treponema pallidum, sera of healthy individuals, or sera from patients with stage I or II of Lyme disease.

Amino Acid Sequence↗
PubMed1991

Comparison of four anti-HIV screening assays which belong to different test generations.

There are three different test generations of enzyme-linked immunosorbent assays (ELISA) for the detection of human immunodeficiency virus (HIV) infection, depending on whether virus lysate, recombinant proteins or synthetic peptides are used as solid phase antigen. Four different assays, i.e., three sandwich ELISAs and one competitive test, were used to demonstrate differences between the three systems with regard to the content of different diagnostically relevant virus proteins. The sensitivities and specificities of these assays were compared by using 312 anti-HIV positive sera and 500 sera of healthy blood donors. The highest sensitivity and specificity were achieved by the competitive ELISA based on recombinant proteins, and by the sandwich ELISA based on synthetic peptides.

Blotting, Western↗
PubMed1990

The antibody response to the HIV-1 specific "out" (vpu) protein: identification of an immunodominant epitope and correlation of antibody detectability to clinical stages.

Overlapping decapeptides based on the sequences of two human immunodeficiency virus type 1 (HIV-1) strains (HXB2 and ELI) were used to identify an immunodominant epitope of the nonstructural protein "out" (vpu) of the human immunodeficiency virus type 1. Of 29 HIV-1 antibody-positive sera, 6 reacted with decapeptides corresponding to the C-terminal amino acid sequence VEMGVEMGHHAPWDVDDL of the "out" (vpu) protein. This oligopeptide was synthesized by the solid phase method and used to develop an enzyme-linked immunosorbent assay (ELISA) for screening of 243 HIV-1-seropositive and 75 HIV-1-seronegative sera. It was found that 26% of the HIV-1 antibody-positive sera were reactive in the "out" (vpu) peptide ELISA, whereas none of the HIV-1-negative sera reacted with the oligopeptide. Correlation of reactivity of sera with the Walter Reed (WR) staging classification demonstrated that individuals classified WR 1 (36%) and WR 2 (42%) were more often reactive than patients classified WR 3-6 (11%).

Amino Acid Sequence↗
PubMed1989

Functional and molecular characterization of a monoclonal antibody against the 165-186 peptide of human IL-1 beta.

A synthetic peptide of human recombinant interleukin 1 beta (hrIL-1 beta) 165-186, which exhibits biological activity in the human fibroblast assay, was used as an immunizing antigen to obtain a murine monoclonal antibody (MoAb) termed FIB 1. This MoAb, an IgG1, reacts specifically with hrIL-1 beta, but not with hrIL-1 alpha, as measured in enzyme-linked immunosorbent assays (ELISA). The MoAb FIB 1 detects the characteristic 17 kDa IL-1 protein in Western blots. Binding to the antigen is specific, as deduced also from the close correlation of ELISA immunoreactivity with IL-1 biological activity. The anti-IL-1 beta 165-186 Ab specifically neutralizes the biological activity of hrIL-1 beta and native IL-1, as measured by the IL-1-induced proliferation of murine thymocytes and human fibroblasts and the IL-1-dependent IL-2 production by murine T cells (EL4-6.1). Fifty per cent of hrIL-1 beta activity (25 U/ml, or 0.25 ng/ml) has neutralized by less than 30 micrograms/ml of MoAb. Furthermore, FIB 1 recognizes intracellular IL-1 in lipopolysaccharide-stimulated human peripheral blood mononuclear cells. The anti-IL-1 beta 165-186 Ab does not react with the shorter IL-1 beta fragment 161-173 in solid-phase ELISA, therefore the binding region seems to be localized in the amino acid sequence VALGLKEKNLYLS. A sandwich-ELISA, using a polyclonal sheep anti-IL-1 beta 251-269 Ab as the capture antibody and an anti-IL-1 beta 165-186 MoAb as the detecting probe, allowed the determination of IL-1 beta from crude culture supernatants.

Animals↗