The influence of the connective-tissue polysaccharides hyaluronate, chondroitin 4-sulphate and a chondroitin 4-sulphate-protein complex (PP-L) from cartilage on the precipitin reaction was investigated. In a system consisting of (125)I-labelled human serum albumin and the immunoglobulin G fraction from rabbit anti-albumin sera, the precipitation is greatly increased in the region of antigen excess. This effect depends on the concentration, molecular weight and configuration of the polysaccharide. The increase parallels a decrease in the amount of soluble immune complexes in the supernatant. It is suggested that the effect is due to steric exclusion of the complexes from the domains of the polysaccharides. The possibility that such a mechanism might enhance precipitation of antigen-antibody complexes in certain pathological conditions is discussed.

Animals↗

PubMed1969

Immune reactions in polysaccharide media. Investigation on complex-formation between some polysaccharides, albumin and immunoglobulin G.

Serum albumin and immunoglobulin G were chromatographed on columns of dextran, hyaluronate and chondroitin 4-sulphate. The partition of the two proteins between hyaluronate and buffer was also measured by equilibrium dialysis. The results accord with the view that there is no complex-formation between the polysaccharides and the proteins in 0.05m-phosphate buffer, pH7.4, containing sodium chloride (0.1m). The observations support the hypothesis that the previously described polysaccharide enhancement of the precipitin reaction is due to exclusion and not to non-specific complex-formation.

Animals↗

PubMed1969

Immune reactions in polysaccharide media. The composition of the antigen-antibody complexes in the precipitin reaction.

The precipitin reaction is enhanced in the presence of polysaccharides (Hellsing, 1966). This reaction has now been studied in detail with labelled antigen ((125)I-labelled human serum albumin) and antibody ((131)I-labelled rabbit anti-albumin immunoglobulin G). The relative proportions of antigen and antibody in the precipitates are unchanged by the addition of dextran in spite of the increased precipitation. The ratio of antibody to antigen in the soluble immune complexes decreases with increasing polysaccharide concentration. This can be interpreted as a decrease in the aggregate size of the complexes. At the same time the amount of free antigen in the solution increases. The results are consistent with a decrease in solubility, primarily of the large immune aggregates, together with a shift in the equilibrium between small and large complexes. The effect is in accord with a steric-exclusion phenomenon.

Animals↗

PubMed1969

Immune reactions in polysaccharide media. Polysaccharide-enhanced precipitin reactions with antigens of various sizes.

The influence of the size of the antigen in the polysaccharide-enhanced precipitin reaction was investigated. The experiments were carried out by addition of homologous antigens of different molecular sizes (the monomer, dimer and trimer of serum albumin and the monomer and dimer of immunoglobulin G) to the same preparation of antibody in the absence and presence of dextran. Dextran decreased the solubility of the immune complexes to a larger extent when the antigen size increased. This is in accord with the view that the polysaccharide effect is due to steric exclusion.

Animals↗

PubMed1969

Immune reactions in polysaccharide media. Experiments with specific antibodies of different affinities for serum albumin.

Rabbit antibody fractions of different affinities for human serum albumin were prepared by an immunosorbent technique. The fractions were used in studies on the enhancement of the precipitin reaction by polymers. Dextran increased the immune precipitation to about the same extent regardless of whether antibodies with high and low affinities were used. The effect should considerably facilitate the detection of antibodies with low precipitating ability in immunological assays. The results are discussed in terms of a steric-exclusion mechanism.

Animals↗

PubMed1966

Immune reactions in polysaccharide media. 1. The effect of dextran on the reaction between iodine-125 labelled human serum albumin and gamma-G-globulin from rabbit anti-albumin sera.

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Animals↗

PubMed1965

Production and drainage of aqueous humor in the cynomolgus monkey (Macaca irus).

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Albumins↗

PubMedDate not supplied

Amino acid concentrations in cerebrospinal fluid in presenile and senile dementia of Alzheimer type and multi-infarct dementia.

Free amino acid levels were measured in cerebrospinal fluid (CSF) from demented patients (D, n = 30) suffering from presenile and senile dementia of Alzheimer type (PDAT, n = 7; SDAT, n = 9), multi-infarct dementia (MID, n = 14) and a reference sample group consisting of young neurotic patients (R, n = 16). Comparing the amino acid levels in the dementia subgroups, significantly higher alanine, methionine, phenylalanine and tyrosine levels were found both in MID and SDAT vs. PDAT. No difference was seen between SDAT and MID. Compared to the reference sample group, higher glycine levels were found in each dementia subgroup; higher alanine, methionine and ornithine levels in MID, and SDAT; and higher phenylalanine levels in MID. In PDAT the level of tyrosine was lower. Coefficients of correlation were calculated between amino acid levels and age, and the findings in the reference sample groups were divergent from those observed in dementia. The differences observed are discussed in terms of amino acid, carbohydrate and neurotransmitter metabolism.

Age Factors↗