Biomedical subjects

A Hautanen

Publications and source records attributed to A Hautanen.

44 records · Page 3Linked to original sources

PubMed1981

Binding of fragments of human IgG to solid-phase C3b measured by enzyme-linked immunosorbent assay (ELISA).

The binding of human IgG and different fragments of IgG to C3b adsorbed to polystyrene tubes has been studied by the enzyme-linked immunosorbent assay. Heat-denatured polyclonal IgG and F(ab')2 and Fab fragments of IgG bound to solid-phase C3b. Heat-denatured Fc fragments of IgG also had some reactivity with C3b, but at significantly higher concentrations than F(ab')2 and Fab fragments. The binding of heat-denatured IgG could not be completely inhibited by the addition of heat-denatured F(ab')2 fragments in tenfold excess. The results suggest that the binding of heat-denatured IgG to solid-phase C3b is mediated through the Fab and Fc portions of IgG molecules.

Antibody Specificity↗

PubMed1981

Characteristics of C3b-binding in chronic liver diseases.

We examined sera from 71 patients, 27 with alcoholic liver disease (ALD), 27 with chronic active hepatitis (CAH), and 17 with primary biliary cirrhosis (PBC), by enzyme-linked immunosorbent assay for the presence of C3b-binding IgG, IgM, and IgA activity (immune complexes and immunoconglutinins). Elevated C3b-binding IgG activity was found in the sera of patients with CAH, PBC (p less than 0.001), and ALD (P less than 0.01). C3b-binding IgM activity was elevated only in CAH and PBC (p less than 0.001) and normal in ALD. Significantly elevated C3b-binding IgA activity was found in all three types of liver disease (p less than 0.005), but it was more prominent in ALD and, moreover, correlated with the severity of the alcoholic liver injury. Ultracentrifugation studies showed that CAH and PBC C3b-binding IgG activity was located in the intermediate (7S-19S) fractions, C3b-binding IgM activity in the heavy (less than 19S) fractions, and C3b-binding IgA activity in the intermediate and partly in the heavy fractions of the sucrose gradient. In ALD, a slight C3b-binding IgG and IgA activity was found in the intermediate fractions of the gradients, but it was most abundant in the heavy fractions. If C3b-binding material is pathogenic, the results suggest that immunopathogenic mechanisms of CAH and PBC differ from those of alcoholic liver injury.

Adult↗

PubMed1979

C3b binding immune complexes and immunoconglutinins in human sera. Detection by enzyme-linked immunosorbent assay (ELISA).

An enzyme-linked immunosorbent assay (ELISA) designed to measure autoantibodies against C3b (immunoconglutinins: IK) also detects immune complexes (IC). Solid phase C3b, in addition to binding IK of IgG, IgM and IgA classes, bound aggregated human IgG, IgA and aggregated immunologically purified anti-tetanus toxid antibodies as well as model complexes of tetanus toxoid-human anti-toxoid. Significant C3b binding IgG, IgM and IgA activities were seen in the sera of 20 SLE patients but not in sera from healthy blood donors. Ultracentrifugation analysis of two SLE sera revealed C3b binding IgG and IgA activities in both light (7S) and heavy (greater than or equal to 11S) fractions. This indicates simultaneous presence of IK and IC in these sera. On the basis of the known relationship between IK and IC formation we suggest that the solid phase C3b ELISA may be of value in evaluating immune reactions in patients.

Antigen-Antibody Complex↗

PubMed1978

Use of ELISA for measuring immunoconglutinins.

An enzyme-linked immunosorbent assay (ELISA) for detection of immunoconglutinins (IKs) has been developed. IKs are allowed to bind to solid-phase C3 and are then assayed using alkaline phosphatase coupled to anti-IgG or anti-IgM. IK activity was detected in some patients' sera up to 50,000-fold dilution. Significant correlation (r = 0.65) was obtained between the levels of IgM-IKs measured by ELISA and by conventional hemagglutination assay, IgG-IKs and hemagglutination titers did not correlate (r = -0.15).

Alkaline Phosphatase↗

PubMedDate not supplied

Aldosterone synthase (CYP11B2) polymorphisms and cardiovascular function.

In addition to regulating renal sodium resorption and, thus, intravascular volume, aldosterone may have direct effects on the cardiovascular system. We previously identified a polymorphism (-344C/T) in the promoter of the aldosterone synthase (CYP11B2) gene that affects binding of the SF-1 transcription factor and thus might influence gene expression. We found that, whereas this polymorphism has inconsistent associations with levels of aldosterone secretion and blood pressure, the -344C allele is strongly associated with increased left ventricular size and decreased baroreflex sensitivity in healthy individuals. These physiological parameters are cardiovascular risk factors. Indeed, preliminary studies suggest that the -344C allele is also associated with increased risk of myocardial infarction in high risk dyslipidemic males.

Alleles↗

PubMedDate not supplied

Fibronectin and viral pathogenesis.

Fibronectin is a dimeric high-molecular-weight glycoprotein composed of two similar but not identical subunits. Differences have been observed between plasma and cell-derived fibronectins, and molecular and sequencing studies have revealed a domain structure. The characteristic features of fibronectin include its various molecular and biologic interactions, which can be assigned to the different domains of the molecule. Fibronectin was originally discovered as a protein missing from the surfaces of virus-transformed cells. The importance of functional oncogenes in the loss of extracellular matrices was later established in a number of studies using virus mutants that are temperature-sensitive for transformation. The loss of the extracellular matrix appears to be a result of multiple events in cells but is not a prerequisite for malignant growth in vivo. There appear to be multiple transformed phenotypes, and the loss of extracellular fibronectin may be due in part to proteolytic activity by the cells and other alterations caused by functioning oncogenes. The wide distribution of tissue and soluble forms of fibronectin offers multiple occasions for interactions with other molecules. Binding of fibronectin to viruses and purified viral proteins has been observed in a number of studies. Neuraminidase-sensitive virus-binding sites in the fibronectin molecule have tentatively been identified. Fibronectin also is capable of binding to various complement components, possibly making clearance of viral antigen-antibody-complement complexes, which are observed in the circulation during viral infection, more rapid. The virus-binding ability of fibronectin may play a role in modifying viral infections in the body.

Animals↗

PubMedDate not supplied

Aldosterone synthase (CYP11B2) polymorphisms and cardiovascular function.

Adult↗

PubMedDate not supplied

C3c-binding in inflammatory rheumatic diseases.

Sera from 73 patients, 24 with rheumatoid arthritis (RA), 10 with Sjögren's syndrome (SS, 4 with and six without RA), 17 with Reiter's syndrome (RS), 10 with systemic lupus erythematosus (SLE), 9 with Yersinia arthritis (YA), and 3 with mixed connective tissue disease (MCTD) were examined by enzyme-immunoassay (EIA) for the presence of C3c-binding IgG, IgM, and IgA activity (C3cBIgG, C3cBIgM, C3cBIgA). This activity probably consists of immunoconglutinins and immunoglobulin aggregates. Significantly elevated C3cBIgG was found in the sera of patients with RA (p less than 0.01), SS, and SLE (p less than 0.02). C3cBIgM was elevated in SS and SLE (p less than 0.02). C3cBIgA was increased in RA (p less than 0.005), in SS and YA (p less than 0.02). Correlations of C3c-binding with erythrocyte sedimentation rate, hemoglobin, C-reactive protein, IgG-binding onto platelets, serum IgG, IgM, and IgA levels, and with rheumatoid factors of IgM and IgA classes were computed. C3cBIgG, C3cBIgM, and C3cBIgA correlated significantly with each other, but usually not with other laboratory variables. The exceptions were positive correlations of C3cBIgM with IgM-rheumatoid factors in RA (p less than 0.05), and with serum IgM levels in the whole series of patients (p less than 0.05). The use of C3c represents a new principle to detect abnormalities in the sera of patients with inflammatory rheumatic diseases. However, the pathogenic significance of elevated C3c-binding remains unknown.

Complement C3↗