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Biomedical subjects

A Hohmann

Publications and source records attributed to A Hohmann.

At least 37 records · Page 2Linked to original sources
PubMed1989

A common anti-cardiolipin antibody idiotype in autoimmune disease: identification using a mouse monoclonal antibody directed against a naturally-occurring anti-phospholipid antibody.

We have recently produced a series of human monoclonal antibodies reacting with cardiolipin. One of these, H3, a polyspecific IgM/k derived from a normal individual, was used to raise mouse monoclonal antibody to its idiotype. Two anti-idiotypic antibodies, S2.9 (IgG2b) and S2.10 (IgM) were selected for their specific reaction with H3.S2.9 did not react with five other human monoclonal antibodies of IgM/k class despite the fact that these shared some antigen-binding characteristics with H3.S2.9 was able to block the binding of H3 to all of its cross-reactive antigens including cardiolipin, while S2.10 was not. S2.9 was equally efficient in blocking the binding of H3 to three of its cross-reactive antigens, cardiolipin, diphtheria and tetanus toxoids; greater than 90% inhibition could be achieved at an equimolar ratio of H3 to S2.9. The anti-idiotype S2.9 was used to demonstrate the presence of the H3 idiotype in serum. This idiotype was found in amounts greater than that seen in 42 normal individuals, in 30 of 36 patients with systemic lupus erythematosus (SLE), eight of 20 patients with rheumatoid arthritis (RA), 8 of 20 patients with Felty's syndrome as well as 10 of 23 patients with syphilis. Not one of nine patients with drug-induced lupus syndrome had abnormal levels. In patients with SLE and Felty's syndrome there was a good correlation between the amount of anti-cardiolipin antibodies and the amount of H3 idiotype (rs = 0.70 and 0.69 respectively). No such correlation was found in syphilitics or in patients with RA. In patients with SLE the H3 idiotype was present on IgM and IgG anti-cardiolipin antibodies. In 15 of 16 SLE sera with high levels of cardiolipin antibody, S2.9 blocked binding of serum antibodies to cardiolipin by 13-72%, with a mean value of 49%. One patient had a high level of anti-cardiolipin antibody which could not be blocked by S2.9. These results indicate that a mouse monoclonal antibody which reacts with an idiotope in the antigen-binding region of a naturally-occurring phospholipid antibody also defines a common idiotype of anti-cardiolipin antibodies in patients with autoimmune disease.

Antibodies, Anti-Idiotypic↗
PubMed1988

Monoclonal alkaline phosphatase-anti-alkaline phosphatase (APAAP) complex: production of antibody, optimization of activity, and use in immunostaining.

A mouse monoclonal antibody, FMC55 (an IgG1), to alkaline phosphatase was prepared and evaluated in immunostaining. Clones producing antibody to alkaline phosphatase were selected using a micro-ELISA which identified antibodies forming active soluble complexes (APAAP) with the enzyme. Conditions that influenced the formation of the complex were investigated by using a quantitative assay in which the complex was captured by a bridging anti-mouse antibody. The ratio of FMC55 to enzyme had a major influence on the activity of the complex. Although all complexes had some activity, those that contained excess antibody had reduced ability to bind to anti-mouse antibody because of competition with excess unlabeled antibody. The optimal complex was formed with 3 micrograms of FMC55 per unit of enzyme. This complex contained neither free enzyme nor free antibody. The molecular weight by gel permeation chromatography was 600,000, giving a composition of two enzyme and two antibody molecules or one enzyme and three antibody molecules. The size of the complex was not altered by adding excess antibody or excess enzyme. Immunoblotting showed that FMC55 bound only to the Mr 140,000 homodimeric form of alkaline phosphatase. The APAAP complex was used in combination with biotin-streptavidin-peroxidase reagent to detect two antigens labeled with two different mouse monoclonal antibodies in the same tissue preparation.

Alkaline Phosphatase↗
PubMed1988

Polyspecific human and murine antibodies to diphtheria and tetanus toxoids and phospholipids.

Human-human hybridomas produced from lymphocytes of normal individuals yielded seven clones producing monoclonal antibody reacting with tetanus toxoid. Three of these antibodies cross-reacted with diphtheria toxoid. These three and two others also reacted with cardiolipin and two with other phospholipids. One of the seven antibodies reacted with tetanus and diphtheria toxoids, cardiolipin and single-stranded DNA. All seven antibodies were IgM. To examine further this unusual cross-reactivity serum antibodies from patients with SLE and healthy individuals were affinity-purified to yield diphtheria toxoid antibodies. Six out of nine of these anti-diphtheria preparations contained IgG antibodies which cross-reacted with tetanus toxoid and two of these also reacted with cardiolipin; four preparations cross-reacted with DNA. Anti-cardiolipin and anti-DNA cross-reactivity were found in preparations from both normal and SLE sera. Similar cross-reactivities were demonstrated using four mouse monoclonal IgM antibodies raised against phospholipids. All four of these antibodies reacted with both cardiolipin and tetanus toxoid and two also reacted with diphtheria toxoid and DNA. Using a thiocyanate elution procedure, it was shown that the cross-reactivity of the monoclonal antibodies was not related to their relative affinities. The results clearly indicate that cross-reactive epitopes occur on routinely used toxoid vaccines and self antigens. Antibodies which bind to these cross-reactive epitopes are common and are not restricted in isotype, affinity or species of origin.

Animals↗
PubMed1985

The human leucocyte P30 antigen: properties and assessment of value as a clonal marker.

FMC3 and FMC29 are monoclonal antibodies which react with a 30,000 Dalton molecule expressed on the lymphocyte surface membrane. The molecule is a protein which does not appear to be N-glycosylated. The antigen, which is also expressed intracellularly, does not appear to be a marker of differentiation or maturation. Polyclonal cell populations, such as peripheral blood lymphocytes, show a bimodal distribution of surface antigen density, whilst monoclonal cell populations analysed quantitatively showed unimodal antigen density distributions. This suggests the antigen may be a clonal marker.

Antibodies, Monoclonal↗
PubMed1984

The antigen of mature human B cells detected by the monoclonal antibody FMC7: studies on the nature of the antigen and modulation of its expression.

The monoclonal antibody FMC7 delineates a subpopulation of B lymphocytes in normal blood. Expression of the antigen recognized by FMC7 appears to be maturation-linked, and it serves to distinguish different types of B cell leukemia. The data presented here indicate that the antigen is a protein that is integrated in the cell membrane and that is able to interact with the cytoskeleton. The antigen is rapidly synthesized and turned over, is not cell cycle-dependent, and is relatively resistant to changes induced by culture in the presence of a phorbol ester.

Antibodies, Monoclonal↗
PubMed1982

[A new test (C-test) for quantitative examination of crowding with test results in amblyopic and ametropic patients (author's transl)].

A new acuity test was developed with a defined space between symbols to determine the effect of crowding on visual line acuity. Landolt-C was used as a symbol and the space between symbols (either 2 to 3 min. of arc or 17 to 18 min. of arc) was kept constant for all acuity values. The test permits a quantitative examination of crowding phenomena. The experimental results obtained in measurements of visual line acuity in normal-sighted, amblyopic and ametropic subjects are presented. The results of treatment for amblyopia had evidently been interpreted too optimistically in many patients hitherto.

Adult↗
PubMed1982

Development of visual line acuity in humans.

An acuity test was developed with defined space between symbols to determine the effect of crowding on visual line acuity. The test differentiates between normalsighted subjects, those with low but uncorrected refractive errors and amblyopes. Furthermore, the test allows a quantitative examination of the crowding phenomenon and a measure of progress during amblyopia therapy. In normal-sighted subjects a maturational effect on visual line acuity was found, reaching the maximum test level at approximately the tenth year of life.

Age Factors↗
PubMed1980

Salmonellosis in mice: studies on oral immunization with live avirulent vaccines.

The avirulent Salmonella typhimurium galE strain G30, following oral feeding to mice, developed a state of immunity to a secondary oral challenge with virulent Salmonella typhimurium. This immunity was concommitant with the development of intestinal and serum antibodies and delayed-type hyepersensitivity (DTH) to Salmonella antigens. In contrast, repeated oral doses of a hybrid E. coli vaccine, which expresses the O antigens of Salmonella typhimurium, provided a lesser degree of immunity and, although able to stimulate the formation of serum antibodies, it elicited only a low level of intestinal antibodies and no measurable DTH.

Administration, Oral↗
PubMed1979

Intestinal and serum antibody responses in mice after oral immunization with Salmonella, Escherichia coli, and Salmonella-Escherichia coli hybrid strains.

After oral feeding of mice with avirulent Salmonella, Escherichia coli, or hybrid strains, only certain bacterial strains were able to multiply and persist within the small intestinal Peyer's patches. After oral vaccination alone, or oral priming and subsequent parenteral boosting, antibody class and titers were detected, using a radioimmunoassay on serum and intestinal fluid or a plaque-forming cell assay on spleens. Only those strains that persisted in the Peyer's patches stimulated the production of serum and intestinal immunoglobulin A antibodies against their respective O antigens. Nonpersistent strains were weakly immunogenic, and antibodies, when present, were largely non-immunoglobulin A and confined to the serum.

Animals↗
PubMed1978

McCollough effect and eye optics.

Astigmatism induced by cylindrical lenses leads to colour sensations similar to the McCollough effect. Consequences for the design of experiments and a new interpretation of the McCollough effect are suggested.

Accommodation, Ocular↗