Search PubMed⌕ Search

Biomedical subjects

B Micheel

Publications and source records attributed to B Micheel.

At least 55 records · Page 3Linked to original sources
PubMed1984

Characterization by Scatchard plots of monoclonal antibody enzyme conjugates directed against alpha-1-foetoprotein.

A radioimmunoassay was used to investigate the affinity of 2 monoclonal antibodies against human alpha-1-foetoprotein before and after conjugation with horseradish peroxidase. The equilibrium constant of the high-affinity antibody was reduced 10-fold whereas it remained unaffected in the low-affinity antibody. With the Scatchard diagram, quantification of unlabelled antibodies in the unpurified conjugate mixture is also possible if antibody affinity is changed by the coupling procedure.

Antibodies, Monoclonal↗
PubMed1984

An antibody chimera technique applied to enzyme immunoassay for human alpha-1-fetoprotein with monoclonal and polyclonal antibodies.

A 2-step enzyme immunoassay (EIA) for human alpha-1-fetoprotein (AFP) is proposed, which uses covalently coupled anti-AFP IgG and anti-horseradish peroxidase (HRP) IgG (antibody chimera) binding HRP as the marker enzyme immunologically. The use of polyclonal and monoclonal anti-AFP linked to anti-HRP antibodies was compared with a conventional 2-site binding EIA with HRP covalently bound to anti-AFP IgG. The sensitivity of the conventional EIA is increased by the use of an antibody chimera comprising a molar ratio of anti-AFP IgG: anti-HRP IgG of 1:8, especially if monoclonal antibodies are employed. This improved sensitivity may be achieved by a very simple coupling procedure without purification of conjugate and with very crude HRP preparations.

Animals↗
PubMed1984

The detection of distinct epitopes of human alpha-fetoprotein (AFP) by solid phase radioimmunoassay using hybridoma culture fluid.

A solid phase radioimmunoassay was developed for the epitope analysis of human alpha-fetoprotein (AFP) using hybridoma culture fluids. The following incubation sequence was performed: anti-mouse Ig, hybridoma culture fluid, normal mouse serum, and a mixture of 125I-labeled AFP and hybridoma culture fluid. Seven epitopes were detected by monoclonal antibodies produced by 15 presumably independent hybridoma clones.

Animals↗
PubMed1983

Comparison of monoclonal and polyclonal antibodies in a two-site binding enzyme immunoassay for alphafetoprotein (AFP).

A two-site binding enzyme immunoassay for the detection of alphafetoprotein (AFP) was developed by using either a combination of two monoclonal antibodies or of one monoclonal antibody and polyclonal antibodies. The conjugation of the monoclonal antibodies to peroxidase by the periodate method yielded a somewhat higher sensitivity in the enzyme immunoassay (EIA), when compared to conjugates produced by the glutaraldehyde method. The detection limit was 10 micrograms AFP per litre when using only monoclonal antibodies in the assay. Simultaneous incubation of the sample and the monoclonal labelled antibody should be avoided unless using at least two different dilutions of the sample for investigation.

Animals↗
PubMed1983

Determination of immunoglobulin class and subclass of monoclonal antibodies to human alpha-fetoprotein by solid phase radioimmunoassay.

A solid phase radioimmunoassay using the incubation sequence: mouse immunoglobulin (Ig) rabbit anti-mouse Ig, monoclonal antibody and 125I-labeled antigen was performed to determine the class and subclass of seven murine monoclonal antibodies against human alpha-fetoprotein. All antibodies belonged to the IgG class. The subclass type was IgG 2a for four antibodies, IgG 1 for two antibodies and IgG 2b for one antibody.

Antibodies, Monoclonal↗
PubMed1983

Type C virus particles in X63-Ag8.653 mouse plasmacytoma cells and in hybridomas derived from it.

In addition to type A virus particles which are common in Balb/c derived mineral oil induced plasmacytomas, type C virus particles have been found in the plasmacytoma cell lines X63-Ag8 and X63-Ag8.653 used in the hybridoma technique. In hybridomas obtained after fusion of X63-Ag8.653 cells with Balb/c spleen cells, C particles were expressed in 5 out of 13 different clones examined, whereas A particles were always present. Virus expression and antibody production do not exclude each other.

Animals↗
PubMed1982

A solid-phase immunofluorescence assay (SIFA) using membrane filters.

A solid-phase immunofluorescence assay (SIFA) is presented which allows the demonstration of antibodies against soluble antigens. The test is performed by successively incubating nitrate cellulose discs in microtitration plates with anti-Ig, the sample to be tested and FITC-labeled antigen. The fluorescence intensity of the discs is then measured by using a microfluorometer. The assay is simple, needs a small amount of material and allows to test a large number of samples.

Animals↗
PubMed1982

Monoclonal antibodies against different antigenic determinants of a protein molecule (human serum albumin) as detected after labeling the antigen with two different markers.

By using FITC- and 125I-labeled human serum albumin (HSA) the reactivity of anti-HSA hybridoma antibodies was compared in solid-phase immunofluorescence assay (SIFA) and radioimmunoassay (SRIA). A considerable number of hybridoma antibodies had been detected which are positive in SIFA but not in SRIA. Since this cannot be explained by a difference in the sensitivity of the assays it seems likely that these monoclonal antibodies detect antigenic determinants which contain tyrosine as an essential part.

Animals↗
PubMed1982

Use of Sepharose bead immunofluorescence assay for comparison of the type D retroviruses MPMV and PMFV.

Mason-Pfizer monkey virus (MPMV) and PMFV, an isolate from a human continuous cell line, were compared by Sepharose bead immunofluorescence assay. According to the results with p27-specific assays the main structural protein of both viruses seems to be identical in the prominent antigenic determinants. Differences were found when comparing the p15s indicating that this viral protein contains type-specific antigenic determinants.

Animals↗
PubMed1982

Search for retrovirus expression in men--failure to demonstrate retrovirus-specific antigens in normal and malignant tissue.

Extracts for different normal and malignant human tissues were checked for retrovirus antigens by Sepharose bead immuno-fluorescence assay. No convincing evidence could be obtained for the presence of type D and mammalian type C virus antigens in the tissues tested by three different immunoassays. It is concluded from these results that such viruses have no ubiquitous distribution in human beings.

Animals↗
PubMed1982

The application of a sepharose bead immunofluorescence assay and a solid-phase radioimmunoassay to the bovine leukemia virus system.

Several fluorescence assays with bovine leukemia virus (BLV) conjugated to activated Sepharose 4B were used for the detection of BLV and anti-BLV antibodies. These tests were compared with a solid-phase radioimmunoassay and found to be in the same sensitivity range. Sepharose bead immunofluorescence assay and solid-phase radioimmunoassay can be applied to the diagnosis of BLV infection in cattle.

Animals↗
PubMed1981

A solid-phase immunofluorescence assay (SIFA) for screening antigen-specific hybridomas.

A solid-phase immunofluorescence assay (SIFA) is described for screening of monoclonal hybridoma antibodies against soluble antigens. The test is simple, needs a small amount of material (20-100 ng of labeled antigen per sample) and allows a large number of samples (500-1 000) to be tested in 2 days. The assay is performed in microtitration plates with small cellulose nitrate discs as the solid phase. Anti-mouse IgG, the sample to be tested and FITC-labeled antigen are successively incubated with the discs. The fluorescence intensity of the surface of the discs is then measured with a microfluorometer. The assay has been used to select hybridomas against human serum albumin. Comparison of the immunofluorescence assay with a radioimmunoassay using conventional antisera and hybridoma antibodies similar sensitivity for both assays.

Animals↗
PubMed1981

[Tumor viruses of nonhuman primates (author's transl)].

Tumor viruses which in the past few years have been increasingly isolated from tissues of nonhuman primates are of considerable interest for contemporary investigations on putative human tumor viruses. This review covers the presently known isolates belonging to the families of papova, adeno, (gamma) herpes, pox, and retro viruses and originating from New World and Old World monkeys as well as from apes. Some of the isolates exhibit oncogenic activity in different simian species and are, therefore, particularly suited for the analysis of viral oncogenesis is primates.

Adenoviridae↗
PubMed1980

Demonstration of C-type viruses in N-methyl-N-nitroso urea (MNU)-induced leukemia of mice by reverse transcriptase activity and XC assay.

A significantly higher MuLV expression was demonstrated in cells of MNU-induced leukemia of mice compared to corresponding cells of untreated control animals by reverse transcriptase activity and XC cell assay. These positive findings were verified by determination of indirect immunofluorescence test to look for intracytoplasmic MuLV p30. The problem is discussed whether these viruses play a role in chemical leukemogenesis.

Animals↗