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A Fomsgaard

Publications and source records attributed to A Fomsgaard.

81 records · Page 5Linked to original sources
PubMed1988

Comparative immunochemistry of lipopolysaccharides from typable and polyagglutinable Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis.

Lipopolysaccharide (LPS) was extracted and purified from three Pseudomonas aeruginosa strains isolated from the infected lungs of patients with cystic fibrosis. Two of the strains could be typed by O-specific antibody (O:3 and O:9), and the third was polyagglutinable (O:3/9). The separated LPS was characterized by chemical and serological methods. The main neutral sugar constituents (glucose, rhamnose, and heptose) were found in various proportions in the three strains, whereas the amounts of glucosamine, galactosamine, ketodeoxyoctonate, and phosphate were more constant. Ester-bound C12, C16, 3-OH-C10, and 2-OH-C12, together with amide-bound 3-OH-C12, fatty acids were present in equimolar proportions in all three strains. Considerable amounts of LPS were liberated in the culture supernatant of the O:3 bacteria but not in those from the other two strains. This free LPS was shown to be immunologically identical to the cell-bound LPS and the extracted LPS. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, O:3 and O:9 LPS showed a ladder pattern characteristic of smooth LPS, while O:3/9 LPS appeared rough. Rabbit antisera used for O-typing were found by enzyme-linked immunosorbent assay to contain anti-LPS antibodies that reacted strongly with homologous LPS, moderately with O:3/9 LPS, and slightly with heterologous LPS. Immunoblotting showed that common antigenic determinants in the core-lipid A part were involved in the observed cross-reaction. The polyagglutinability of P. aeruginosa may be explained by the antibodies to these common determinants that arose from the partial absence of O polysaccharides.

Antigens, Bacterial↗
PubMed1987

ELISA for human IgG and IgM anti-lipopolysaccharide antibodies with indirect standardization.

A new attempt to standardize ELISAs for the quantitation of human IgM and IgG anti-lipopolysaccharide antibodies (anti-LPS), without the use of a specific standard material, is described. Sandwich ELISAs for total IgG and IgM were combined with indirect ELISAs for anti-LPS IgG and IgM antibodies on a 96-well microtest plate using identical assay conditions. The concentration of specific IgG or IgM anti-LPS was read on the respective standard curve for total IgG or IgM. The results were corrected for residual immunoreactivity remaining unbound in the wells after one sample incubation in the combined assays. The quantitative results of IgG anti-LPS correlated well with results obtained using an ELISA with direct standardization (r = 0.969). 28 mg/l of IgM anti-LPS was found as median value among 121 blood donors using the described ELISA principle. Binding studies demonstrated a lower apparent affinity of donor anti-LPS IgM than anti-IgG.

Enzyme-Linked Immunosorbent Assay↗
PubMed1987

Anti-lipopolysaccharide antibodies measured by enzyme-immunoassay in Danish blood donors.

To explore whether the intravenous administration of naturally occurring high-titer human anti-lipopolysaccharide IgG (anti-LPS) is beneficial in the treatment of human septic shock, it is necessary to select blood donors according to anti-LPS concentrations. The present paper describes an enzyme-linked immuno-adsorbent assay (ELISA) for the screening of blood donors to obtain such antibodies. Human specific IgG antibodies directed against smooth LPS from eleven different bacterial strains and species were quantitated. The ELISA is simple and uses only commercially available reagents. By optimizing assay conditions, a low unspecific background activity (OD below 0.010) was obtained, together with a large specific reading interval. 2021 human plasma samples from volunteer blood donors at six different blood-banks in Denmark were screened by the ELISA. The median anti-LPS antibody concentration was 9 mg/l. Five per cent of the donors had anti-LPS concentrations above 40 mg/l (expected to be therapeutically useful). The age- and sex-related distributions indicated that the highest prevalence of high anti-LPS concentration was in males aged 40-49 years. It is concluded that specific anti-LPS gammaglobulin based on naturally occurring anti-LPS antibodies can be obtained in Denmark following the screening of blood-donors, using the assay developed.

Adult↗
PubMed1987

Micro-ELISA for the quantitation of human urinary IgG.

When investigating glomerular changes in the early stages of diabetic renal disease, it is important to be able to estimate low concentrations of urinary immunoglobulins, as well as the albumin/immunoglobulin ratio. For this reason there is a need for highly sensitive and specific routine assays for urinary immunoglobulins. A 'sandwich' enzyme-linked immunoadsorbent assay (ELISA) for the quantitation of urinary immunoglobulin G is described, in which microtest plates are used as the solid phase. The assay is specific, sensitive and simple, and only used commercially available reagents. The assay range was 5-200 micrograms/l. The relative standard deviations within and between assays were 5 and 9%, respectively. Recovery of IgG added to urine was 100-102% (n = 12), and dilution of urine was linear. The assay range allowed for the quantitation of IgG in human urine samples, covering the clinical range from physiological to raised pathological values.

Enzyme-Linked Immunosorbent Assay↗
PubMedDate not supplied

ELISA for antibodies to lipid A, lipopolysaccharides and other hydrophobic antigens.

A simple, sensitive and rapid ELISA method for the quantification and characterization of antibodies to lipid A has been developed, which can also be applied to other hydrophobic antigens. For coating, antigens were applied to the wells of ELISA plates as solutions in a mixture of chloroform and ethanol 1:9 (v/v), and the solvent evaporated in a stream of warm air. Under these conditions a high coating efficiency was achieved, which made the assay highly sensitive. The use of the above organic solvent considerably reduced the nonspecific adsorption of immunoglobulins to the solid phase, making the usual blocking of unspecific binding sites with BSA or gelatine unnecessary. For screening of lipid A antibodies in the sera of immunized animals, coating with 0.2 microgram of the corresponding antigen per well was found to be suitable. For optimal measurement of antibodies in pre-immune sera, sera of healthy human donors, and of monoclonal antibodies, higher amounts of antigen (1-2 micrograms/well) had to be used. The coating method described here proved excellent also for other antigens directly soluble in organic solvents, such as Re-lipopolysaccharide (LPS) or gangliosides. In addition, the method was successfully applied to less hydrophobic antigens, such as LPS of the classes Ra to Rd and S forms, and lipoteichoic acid. These could be brought into solution in chloroform/ethanol by diluting their aqueous solutions with a large volume of the organic mixture.

Adolescent↗
PubMedDate not supplied

Specific IgG2 antibodies to Pseudomonas aeruginosa lipid A and lipopolysaccharide are early markers of chronic infection in patients with cystic fibrosis.

The IgG subclass antibody response to the two parts of Pseudomonas aeruginosa lipopolysaccharide; endotoxic lipid A and the O-polysaccharide, were investigated in a retrospective longitudinal study involving 16 patients with cystic fibrosis and chronic P. aeruginosa lung infection. The purpose of the study was to see if any of the IgG subclasses of either specificity could be used as prognostic markers in the development and subsequent course of the lung disease. IgG2 anti-lipid A, IgG3 anti-lipid A, and IgG2 anti-polysaccharide showed a significant positive correlation with deteriorating pulmonary function already before chronic P. aeruginosa lung infection was diagnosed as well as in subsequent years. The findings suggest antigenic exposure of the patient before chronic infection is detected by routine sputum examinations, and further support our previous findings of a critical role of the IgG subclass response in modulating the course of inflammatory lung damage in these patients.

Adolescent↗