Precipitation Of Antigen-antibody Complexes Research Articles

CLINICAL AND NEUROLOGICAL PECULIARITIES AND THE LEVEL OF AUTOANTIBODIES TO NEUROSPECIFIC ANTIGENS IN PATIENTS WITH CHRONIC HEMOBLASTOSIS

The purpose of this study was to determine the level of autoantibodies to neurospecific antigens and their relationship with clinical manifestations of the nervous system lesions in chronic hematological malignancies. Materials and methods. The study included 86 patients with chronic hemoblastosis divided into 3 groups: group 1 consisted of patients with chronic lymphoid leukaemia (n = 30), group 2 involved patients with chronic myeloid leukaemia (n = 30), group 3 included patients with multiple myeloma (n = 26). 21 inpatients of the neurological hospital without immunological and hematological disorders were selected as a control group. We investigated the anamnestic data on the presence of a clinical diagnosis of the nervous system lesions before and after the establishing a cancerous hematological diagnosis, carried out a complete neurological examination of the patients with chronic hematoblastosis to determine main neurological syndromes. The level of peripheral blood autoantibodies to neurospecific antigens was evaluated by the enzyme immunoassay. The level of circulating immune complexes was determined by the method of selective precipitation of antigen-antibody complexes. The findings of the study were statistically processes by using Microsoft Excel 2019 and IBM SPSS Statistics 26.0 software. The data obtained were processed by descriptive statistics methods. The study has demonstrated that encephalopathy (70%) and radiculopathy (40%) develop statistically significantly more often in the patients with chronic lymphoid leukaemia. The patients with chronic myeloid leukaemia are found to have encephalopathy (43%) and polyneuropathy (20%). The development of multiple myeloma is statistically significantly accompanied by the occurrence of radiculopathy (50%) and polyneuropathy (53%). Conclusion. The nervous system lesions are found considerably frequent in the patients with chronic hematological malignancies. The development of secondary encephalopathy in the patients with chronic lymphoid leukaemia may develop as a consequence of paraneoplastic syndrome due to the excessive production of cytokines and plasminogen activators. The predominance of radiculopathy in chronic myeloid leukaemia can be reliably explained by the high severity of the proliferative syndrome with a tendency to the production of localized chlorine, which can compress the corresponding roots of the peripheral nerves. However, peripheral lesions of nervous system are more typical for patients with multiple myeloma that may be due to hyperparaproteinemia combined with the chemotherapy of the underlying disease. Along with this, chronic lymphoid leukaemia and chronic myeloid leukaemia cause an increase in the circulating immune complexes level. Immunological changes indicate significant damage to nerve fibres and considerably rapid destruction of neurons in all forms of chronic hemoblastosis.

A protein A-binding, polyethylene glycol precipitation-based immunoradiometric assay: Application to the detection of immune complexes and C3 in human sera and of private antigens in cross-reacting parasite extracts

An immunoradiometric assay, based on the precipitation of antigen-antibody complexes by polyethylene glycol (PEG) and on the subsequent binding of PEG-soluble radiolabelled staphylococcal protein A to the PEG-insoluble complexes, is described. The assay can be applied to the detection of naturally occurring, circulating immune complexes, and of complexes artificially created by mixing antigen and antibody solutions, which makes it of potential use for the detection of either antigen or antibody in several situations. Pre-treatment of the antibody-containing sera with 3% PEG greatly reduced the background values and increased the sensitivity of the assay. The assay was also applied to the detection and isolation of (1) Leishmania donovani antigens that did not cross-react with antigens of the related parasite Tryoanosoma cruzi (private antigens) and (2) private antigens of insect-derived metacyclic trypomastigotes of T. cruzi in relation to culture-derived metacyclic trypomastigotes of T. cruzi A simple and extremely effective procedure for washing precipitates with just one centrifugation is also described.

An inhibitor of complement-mediated prevention of immune precipitation in rheumatoid arthritis--relationship to disease activity and systemic manifestations.

In normal serum complement prevents precipitation of antigen-antibody complexes (PIP). However rheumatoid arthritis (RA) serum contains an inhibitor of this complement-mediated function. We have undertaken two prospective studies in order to look for any relationship between the presence and levels of inhibitory activity in sera and synovial fluids (SF) of patients with RA and disease activity (study A), and the presence of systemic manifestations (nodules and vasculitis) of RA (study B). In study A, levels of inhibitory activity were highest in the sera and synovial fluids of patients with seropositive RA. However there was no correlation between the inhibitory levels and indices of generalised disease activity (articular index, erythrocyte sedimentation rate (ESR), haemoglobin, white cell and platelet counts). Local joint tenderness score correlated weakly with the inhibitory level in SF (P less than 0.05). There was no correlation, however, with either the SF protein concentration or white cell count. In study B, PIP was shown to be lower in patients with the systemic manifestations of RA than in those with purely articular manifestations. PIP was particularly low in those patients with vasculitis compared to those with subcutaneous nodules. Serum levels of inhibitory activity were highest in patients with vasculitis and lowest in those with articular disease only, whereas patients with nodules had intermediate levels. Our conclusion is that inhibition of immune precipitation is not associated with disease activity, but is associated with the extra-articular manifestations of RA. The inhibitory factor may play a role in the pathogenesis of RA.

Immunoassay of O6-methyldeoxyguanosine in DNA: The use of polyethylene glycol to separate bound and free nucleoside

Radioimmunoassay (RIA) method has been established for O 6-methyldeoxyguanosine ( O 6-medGuo), using precipitation with polyethylene glycol (PEG) to separate bound and free alkyldeoxyguanosine and antisera of higher affinity (1 × 10 9 M −1) and titre (1:10000) than previously reported. The lower limit of detection (2 S.D. from zero standard) is 40 pg (0.14 pmol) of O 6-medGuo. Hydrolysates of non-alkylated DNA extracts show interference in the precipitation of antigen-antibody complex, thus making necessary the construction of a standard curve with the same amount of DNA hydrolysates as in the sample to be analysed. Precision of the method was assessed using DNA hydrolysates from livers of rats injected with 15 mg/kg dimethylnitrosamine (DMN). Within assay variation of a single DNA extract was 85.9 ± 5.9 ng/mg DNA ( n = 5, CV = 6.9%). Day-to-day variation of the assay for four DNA extracts measured over 3 days were (ng/mg DNA S.D.), 99.8 ± 6.9, CV = 6.9%; 88.2 ± 6.5, CV = 7.4%; 81.3 ± 3.9, CV = 4.8%; 77.0 ± 6.4 CV = 8.3%. Coefficient of variation was 10.8% with DNA hydrolysate spiked with a known concentration of O 6-medGuo and assayed ( n = 5). Cross-reactivity of one of our best antisera coded R68/4, and raised against O 6-medGuo-BSA conjugate were: O 6-methylguanosine ( O 6-meGuo), 9.6%; O 6-methylguanine ( O 6-meGua), 0.4%; O 6-ethylguanine ( O 6-EtGua), 0.12%; 7-methylguanosine (7-meGuo), 0.03%; 2′-deoxyadenosine (2′-dAdo), 0.007%; 2′-deoxyguanosine-5′-monophosphoric acid (2′-dGuoMP), 2′-deoxyguanosine (2′-dGuo), 7-meGua and 7-meGuo did not significantly inhibit the binding of O 6-me[1′-2′- 3H]dGuo at concentrations of up to 10 μg/tube. The application of such methods underline the potential of RIAs for quantification of DNA components structurally modified by non-radioactive carcinogens.

Specificity of allozyme-absorbed antisera to human placental alkaline phosphatase for individual phenotypes.

Antisera raised against the rare FD phenotype enzyme were exhaustively absorbed with SS and FF phenotype enzyme immobilized on agarose gels. When it was absorbed with the FF phenotype enzyme, the antiserum no longer reacted with the F-variant enzyme, but did with the S-, D-, and I-variants, as determined by electrophoretic retardation experiments and precipitation of antigen-antibody complexes using staphylococcal protein A. When the antiserum was absorbed with SS phenotype enzyme, it no longer reacted with S-, D-, or I-variant enzyme, but did have some reactivity with the F-variant, as seen in the protein A assay. Based upon the IgG concentration, which bound 40% of the appropriate enzyme, 1/20 of the antiserum preparation was specific for the S-, D-, and I-variant shared specificity, and 1/400 was specific for the F-variant alone.

Failure of the usual anti-Ig antibody method for quantitative measurement of low affinity antibodies.

The usual anti-Ig antibody method, consisting of the precipitation of soluble antigen-antibody complexes by heterologous anti-Ig antibody, was applied for quantitative estimation of guinea pig IgG2 anti-ovalbumin and anti-2,4-dinitrophenyl (DNP) antibodies by measuring the maximum amounts of antibody-bound antigens. However, the amounts of antibodies estimated were less than those obtained by other methods: the precipitin reaction, the precipitation of antigen-antibody complexes with 50% saturated ammonium sulfate, and equilibrium dialysis. In particular, the anti-Ig antibody method greatly underestimated the amount of anti-DNP antibody with low affinity for epsilon-DNP-L-lysine. Thus, it was concluded that partial dissociation of the antigen-antibody complexes occurring upon precipitation with anti-Ig antibody made the anti-Ig antibody method unsuitable for quantitative determination of antibodies.

A molecular explanation of stress dermatitis.

In contact dermatitis, delayed type allergy usually occurs in conjunction with immediate type. The latter type of response depends upon precipitation of antigen-antibody complexes within the vessel wa

Polymer-induced precipitation of antigen-antibody complexes: 'Precipiplex' reactions

Polymer-induced precipitation of antigen-antibody complexes: 'Precipiplex' reactions

Unstable complexes of I 125-labeled house dust and an antibody-like globulin from human sera

The direct reaction between a radioiodine-labeled purified house dust allergen and human sera has been studied by precipitation of antigen-antibody complexes with cold ethanol. Antibody was found in sera of 8 of 16 nonallergic persons and 27 of 32 of those allergic to dust. The antibody was not found in significantly greater quantites in sera of patients who had received house dust injections than in sera of untreated patients. The antibody was destroyed by heating to 56° C. for 1 hour, by exposure to pH 4 for 2 hours, and by incubation with mercaptoethanol for 30 minutes. It was found predominately in the euglobulin fraction of serum. The reaction was inhibited by excess unlabeled house dust but not by a variety of other antigens. These antigen-antibody complexes vanished during prolonged incubation at 37° C., decaying in a reaction exhibiting first-order kinetics. The rate of decay was temperature dependent. It was inhibited by heavy metals, soybean trypsin inhibitor, some synthetic ester substrates of chymotrypsin, indol, and β indol acetic acid. It was not inhibited by 1.5 molar sodium chloride, ethylenediamine tetraacetic acid, phenol, iodoacetic acid- N-ethyl maleimide, p-mercuribenzoic acid dl tryptophane, glucuronolactone, salicylate, diisopropyl fluorophosphate, or epsilon-amino caproic acid.

Antibody studies in rabbit encephalomyelitis induced by a water-soluble protein fraction of rabbit cord.

A water-soluble protein fraction of nervous tissue was prepared by extraction of rabbit spinal cord with sodium citrate at pH 4.3. Characterization by nitrogen content and paper electrophoresis showed it to be a mixture of basic proteins. This extract demonstrated encephalitogenic activity when injected into rabbits. The most suitable technique for the measurement of serum antibody to the rabbit cord antigen proved to be the precipitation of antigen-antibody complexes by 40 per cent saturated ammonium sulfate. Antibody could not be demonstrated by the techniques of complement fixation, quantitative precipitation, and Ouchterlony plates. The early appearance of circulating antibody occurred almost exclusively in rabbits that subsequently developed EAE. Specificity of the antibodies for nervous tissue was demonstrated by appropriate blocking and adsorption experiments.