[Role of circulating immune complexes in the development of postoperative complications after cataract extraction]. / Rol' tsirkuliruiushchikh immunnykh kompleksov v razvitii posleoperatsionnykh oslozhnenii u bol'nykh pri ékstraktsii katarakty.

Physical and chemical parameters of immune complexes were studied in cataract patients before and after surgery with laser nephelometry. The authors suggest a possible uveitogenous role of the circulating immune complexes of medium size (from 7 to 21 IgG) and high concentration (over 1.2 mg/ml) in the development of postoperative complications of an inflammatory nature.

[Physico-chemical properties of circulating immune complexes in blood and tears of cataract patients in the pre- and post-operative period]. / Fiziko-khimicheskie svoistva tsirkuliruiushchikh immunykh kompleksov vsyvorotke i sleze bol'nykh s kataraktoi v do- i posleoperatsionnom periode.

We have studied physical and chemical properties of the circulating immune complexes of cataract patients before and after surgery as well as the influence of the technique of cataract extraction on the human organism inflammatory reaction, particularly on the lowering of concentration and dimensions of immune complexes in blood serum and tears. There is a hypothesis advanced on the influence of the immune complexes on the development of postoperative uveitis.

Galactose-containing epitopes on the surface of IgG model immune complexes are accessible for specific binding with the high molecular weight ligand, Ricinus agglutinin, in solution-light-scattering studies.

Immunoglobulin G (IgG) molecules contain covalently linked carbohydrate chains with galactose residues in their branched "antennae". The ability of galactose-containing epitopes on the surface of IgG model immune complexes (IC) to interact with a high mol. wt ligand in solution has been elucidated. Different types of IgG model IC with pre-determined molecular mass were mixed with Ricinus Agglutinin (RCI), which is known to bind specifically to galactose-containing oligosaccharides. The relative light-scattering increases (delta I) in the reaction mixture were measured as a function of time. The galactose-associated epitopes of the IgG model IC were accessible for binding with RC1. The rate of the interaction between IgG model IC and RC1 was dependent on the molecular mass of the complexes; the larger the model IC molecular mass, the faster the rate of interaction. The binding of RC1 to IgG model IC was highly specific because it was completely abolished in the presence of lactose. The galactose-containing epitopes of monomeric IgG were also able to interact with RC1 but the kinetics of the interaction was much slower. We suggest than an increase in the density of the epitopes on the surface of the model IC, by close attachment of the IgG molecules, mainly determines the ability of galactose-containing epitopes to be recognized by RC1. The data presented support the importance of IgG glycans in recognition events of IgG by biologically active molecules.

[Interaction of model IgG complexes with lectin from Ricinus communis in solutions studied by light scattering method]. / Vzaimodeistvie model'nykh IgG kompleksov s lektinom kleshcheviny obyknovennoi v rastvore po dannym metoda svetorasseianiia.

In order to demonstrate the participation of galactose-containing carbohydrate epitopes on the surface of model IgG complexes (MIC) during their interaction with high molecular weight ligands, MIC were obtained. The interaction of MIC with Ricinus communis agglutinin (RCA) was studied. The time-dependent changes in the intensity of light scattering in solutions containing MIC of different molecular masses were measured after addition of RCA. It was shown that the efficiency of MIC interaction with RCA depends on the molecular mass of the former. The binding of RCA to MIC is highly specific, it being completely abolished after addition of lactose (1-15 mM). It was found that the final lactose concentration necessary for the complete inhibition of MIC interaction with RCA to take place, depends on the molecular mass of MIC. The data obtained point to the accessibility of IgG oligosaccharide antennae within the composition of MIC for the binding to high molecular weight ligands as well as to the increased density of galactose-containing epitopes on the surface of MIC resulting from the increase in their molecular mass.

Production and characterization of heat-aggregated IgG complexes with pre-determined molecular masses: light-scattering study.

A method for the preparation of model immune complexes of heat-aggregated human IgG with predetermined molecular masses is described. IgG complexes with different molecular masses were produced by incubation of human IgG for 20 min at 63 degrees C, the protein concentration varying from 0.5 to 5 mg/ml before heat treatment. To determine the bulk of IgG molecules included in the aggregates, the IgG complexes obtained were precipitated by 7% polyethylene glycol. The relative molecular masses of the heat-aggregated IgG preparations were calculated using light-scattering measurements, being expressed as the number of IgG molecules per aggregate (MIC/MIgG). The dependence of the MIC/MIgG value upon IgG concentration in aggregation was plotted. This dependence makes it possible to produce IgG model immune complexes with pre-determined molecular masses.

A method for quantitative determination of average masses and concentrations of circulating immune complexes in human sera.

A method for rapid determination of average masses and concentrations of circulating immune complexes in human sera is suggested. It is based on the dissimilarity in solubilities of immune complexes with different masses in the presence of polyethyleneglycol. Light-scattering intensities are measured by a laser nephelometer after adding to the serum of PEG in two different concentrations. The experimental values of the average masses and concentrations are calculated using calibration curves. The calibration curves are plotted for model immune complexes with different average masses obtained by heat-aggregation of IgG at various concentrations. This technique has been employed for determination of the average masses and concentrations of circulating immune complexes in 17 patients suffering from systemic lupus erythematosus and in 8 control individuals.

[Complement-binding capacity of aggregated immunoglobulins of different molecular weights]. / Komplementsviazyvaiushchaia sposobnost' agregirovannykh immunoglobulinov razlichnykh molekuliarnykh mass.

The complement-fixing capacity of aggregated immunoglobulins with varying molecular weights has been explored. It has been demonstrated that as the molecular weight of a complex rises, the complement-fixing capacity increases. The amount of unfixed complement depends nonlinearly on the concentration of complement added and aggregated complexes in solution. The size of the complexes rather than their concentration plays the key role in the measurement of the complement-fixing capacity of aggregated immunoglobulins.