[Changes in the orientation of mouse myeloma immunoglobulin G in monolayers after treatment with sodium deoxycholate].

Molecules of normal mouse IgG are oriented horizontally in monolayers at air-water interface unlike the molecules of mouse IgG1 kappa secreted by MOPC-21 myeloma which have vertical orientation. Sodium desoxycholate processing of both preparations at concentrations below the critical micelle concentration resulted in abnormal IgG1 kappa preservation and normal IgG acquisition of vertical orientation in monolayers. When sodium desoxycholate was used for IgG modification at concentration higher than the critical micelle concentration both normal and abnormal IgG had horizontal orientation in monolayers.

[Regulation of the orientation of the IgG and IgM molecule at the interface].

Pathological immunoglobulins (IgG from patients with multiple myeloma and IgM from patients with Waldenström macroglobulinemia) have been shown to possess hydrophylic-lipophylic balance (HLB) which differed from normal Ig HLB. HLB deficiency in pathological proteins was due to the increase of hydrophobic area at the surface of protein globe, which was the reason for different normal and abnormal Ig orientations at the aqueous NaCl solution--air interface. The normal IgG and IgM had horizontal orientation while abnormal ones had vertical orientation.

[Heat denaturation of immunoglobin G in monomolecular layers].

Studies were carried out of viscous-elastic properties of monomolecular layers of human immunoglobulin IgG formed at the interface water solutions of NaCl--air within 20 degrees C to 50 degrees C at NaCl concentration in sublayer from 0.3 to 1.0 M.

[Complement-binding activity of myeloma and normal immune complexes].

The comparison of complement-fixing capacity of simulated immune complexes formed by normal IgG and IgG, isolated from serum of patients with multiple myeloma, has been performed. In both cases a non-linear dependence of complement-fixing capacity on the complex molecular mass was demonstrated, it being higher for myeloma proteins. Complement supplementation to high molecular complexes leads to their collapse, with normal immune complexes destroyed at lower molecular masses.

[Orientation and kinetics of surface denaturation of normal human and myeloma IgA in monolayers at the interface of air-NaCl aqueous solutions].

Normal serum immunoglobulin A (IgA) and abnormal IgA isolated from serum of patients with multiple A-myeloma have been studied by monolayer technique at air--NaCl solution interfaces. Normal IgA analogous to human normal IgG and secretory IgA was shown to have horizontal orientation at air--water interface. Only some abnormal IgA were similar to myeloma IgG and differed from the normal ones by their orientation at phase border.

[Structural studies of human IgA1 and IgA2 immunoglobulins labeled with two different spin labels].

The spin-label method was used for structural study of different subclasses of human immunoglobulin A. The spin label was incorporated into the protein part, as well as into carbohydrates of the IgA molecules. Well resolved outer wide extrema were characteristic of the ESR spectra of IgA spin-labeled at the protein moiety.

[Identical nature of the differences between normal and myeloma IgG in the mouse and man determined by the monolayer method].

The surface denaturation kinetics of mouse normal IgG and IgGl kappa secreted by myeloma MOPC-21 was studied in monomolecular layers at the air-water interface. Based on the denaturation kinetics data the orientation of the native IgG molecules was determined relative to the interface surface, which turned out to be horizontal for normal IgG and vertical for myelomic ones. As regards the orientation in the monolayers and the rate of surface denaturation, the mouse normal IgG were found to be similar to normal IgG from other species.

[Comparison of the complement-binding activity of model immune complexes of different molecular weights].

The authors studied and compared the complement-fixing activity of model immune complexes with different molecular mass. The complement-fixing activity of the complexes was found to be linearly independent of the molecular mass, being mainly determined by the size of the complex, and to be slightly dependent on the concentration of aggregated immunoglobulins. As far as the aggregates with a molecular mass over 20 IgG are concerned, addition of complement leads to the dissociation of the complexes.

[Mechanism of the piezoelectric polarization of collagen].

Dipole structure and mobility of dipoles in helical regions of collagen macromolecules were analysed. The mechanism of shearstressed piezoelectric polarization was proposed. On the proposed model quantitative calculations were carried out; the obtained value of coefficient e14 for oriented artificial collagen film comes to an agreement with experimental meaning.

[Conformation stability of immunoglobulin A by the monomolecular layer method].

Human secretory immunoglobulin A (IgA) resistance to surface denaturation as a function of NaCl concentration and pH of aqueous phase has been studied by monomolecular layer method at air-water interface. Ig A has been shown to form monolayers of native molecules oriented horizontally towards interface in pH range from 5.2 to 9.

[Comparative study of normal and myelogenic immunoglobulin G in monomolecular layers at air-water and oil-water interface].

Orientation of normal and 12 abnormal immunoglobulins G (IgG) isolated from serum of patients with multiple myeloma in monomolecular layers at 0.15 M NaCl--air and 0.15 M NaCl--octane interfaces has been studied.

[Study of Monomolecular layers of immunoglobulin G by IR-spectroscopy].

The deposited immunoglobulin G (IgG) monomolecular layers consisting of native protein molecules oriented either horizontally or vertically towards the Si internal reflection plate, and also of molecules, denatured in monolayers at air-water interface have been studied by attenuated total-reflection (ATR) IR-spectroscopy technique. It was shown that deposition of IgG molecules on Si surface from monolayers at air--water interface did not change conformation and orientation of the molecules. The value of monolayer thickness correlates with the IgG molecule dimensions calculated from X-ray diffraction data.

[Conformational stability of immunoglobulin G in monomolecular layers at aqueous NaCl solution-octane interfaces].

Resistance to surface denaturation of human and horse immunoglobulin G (IgG) molecules at aqueous NaCl solution--octane interface as a function of aqueous phase pH and NaCl concentration has been studied by monomolecular layer method. Higher conformational stability of these proteins at oil--water interface as compared to that at air-water interface has been demonstrated. At aqueous solutions of 0.

[Orientational, conformational stability and surface potential of immunoglobulins in monomolecular layers].

Orientation, resistance to surface denaturation and surface potential of bovine and horse immunoglobulin G (IgG) and also of pig IgG-antibodies against DNP and DNS groups on the surface of NaCl solutions of various concentrations have been studied by monomolecular layer method. High conformational stability of IgG molecules of all the species was confirmed. At the surface of NaCl solutions with concentrations 0.

[Study of IgE by thermistography].

The authors studied the possibilities of applying thermistography to the determination of IgE in human blood serum. It was shown that IgE is thermolabile, precipitating at the equivalent antigen/antibody ratios and at pH 5.5-7.

[Relation between surface denaturation of immunoglobulin G in monolayers and the pH of the solution].

Dependence of surface denaturation kinetics of rabbit immunoglobulin G (IgG) in monomolecular layers at air-water interfaces on the substrate pH has been studied. By measuring the surface potential the drift of the isoelectric point of IgG in monolayer as compared to that of the bulk aqueous phase in the direction of high pH values has been demonstrated. The IgG molecule displays the greatest stability in monolayer at the isoelectric point.

[Molecular mechanisms of formation of complexes between complement and immunoglobulins].

The mechanism of complement complexing with immunoglobulins in the solution has been shown to depend on the nature and structure of the reagents. The maximum complexing rate can be recorded during interaction of the native complement with aggregated antibodies. The complexing rate varies with the complement type.