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At least 19 recordsLinked to original sources
PubMed1980

Immunobiological behaviour of rabbit precipitating and non-precipitating (co-precipitating) antibodies.

Complement fixing capacity, antibody-dependent cell cytotoxicity and in vivo opsonic function of rabbit anti-DNP precipitating and co-precipitating antibodies were analysed. Precipitating antibody activated the complement system, but co-precipitating antibody did not. Both antibody preparations behaved similarly in antibody-dependent cytotoxicity reactions. When chicken erythrocytes were employed as target cells, both antibodies were inactive with homologous (rabbit) lymphocytes as effector cells but were active with heterologous lymphoid effector cells (human, guinea-pig). Clearance of antigen from the blood of mice was accelerated following injection of an optimal dose of precipitating antibody but co-precipitating antibody was ineffective even at different doses. Competition between precipitating and co-precipitating antibodies in complement fixation and antigen elimination following interaction with antigen successively or at the same time was investigated. In these tests, both antibodies competed with antigen by mass but not by affinity. The possibility exists that co-precipitating antibody has one high and one low affinity binding site and thus acts as an univalent blocking antibody and is therefore not able to form active complexes with antigen. The possible role of co-precipitating antibody in some humoral and cellular immune mechanisms is discussed.

Animals↗
PubMed1984

Structural studies of sheep IgG1 precipitating and co-precipitating antibodies.

Descriptions have previously been given of the physiochemical and immunobiological behaviour of IgG co-precipitating antibodies, isolated from different animal species, compared with that of the precipitating ones belonging to the same immunoglobulin class. From those investigations it seems reasonable to assume that only one of the combining sites present in the two binding arms of the co-precipitating antibody molecule firmly binds the antigen. Consequently, the antibody does not form insoluble Ag-Ab complexes. The peptide maps, diagonal peptide maps and high voltage electrophoresis developed with peptides obtained after previous reduction and radioactive alkylation did not show differences between sheep IgG1 precipitating and co-precipitating antibodies. When diffused against rat anti-sheep IgG1 precipitating antibody serum, sheep IgG1 precipitating antibody gave a band of precipitation which was identical to the band given by sheep IgG1 co-precipitating antibody. Similar results were obtained when rat anti-sheep IgG1 co-precipitating antibody serum was used for precipitation. By immunodiffusion with cross absorbed sera no antigenic differences between the two antibodies could be demonstrated. The results obtained indicate that the different behaviour of precipitating and co-precipitating antibodies when interacting with antigen would probably not be a consequence of differences in the primary structures of their constant fragments. Both antibodies would belong to the same class, sub-class or type of immunoglobulin.

Animals↗
PubMed1995

Characterization of epitopes in native and unfolded cobrotoxin: evidence of an immunodominant C-terminal region related to the production of precipitating and non-precipitating antibodies against cobrotoxin.

Rabbits hyperimmunized with cobrotoxin from Taiwan cobra venom produced non-precipitating as well as precipitating antibodies. Both antibody preparations exhibited higher affinity for native cobrotoxin than for reduced and S-carboxymethylated (RCM) cobrotoxin. This indicated that the epitope structures in cobrotoxin are mostly conformation-dependent. In order to identify the conformational epitopes, native cobrotoxin was hydrolyzed with acid protease A, and 12 peptides were obtained on HPLC. Three peptide fragments, AP-10, AP-11, and AP-12, showed pronounced antigenicities toward precipitating as well as non-precipitating antibodies. AP-10, AP-11, and AP-12 contained a common segment in the C-terminal region of cobrotoxin, residues 43 to 62, with intact disulfide linkages. Complete removal of the C-terminal antibodies from antisera and precipitating antibodies on a C-terminal segment-Sepharose affinity column resulted in the loss of their precipitability with cobrotoxin, whilst restoration of precipitability was observed on the addition of the C-terminal antibodies to the C-terminal antibody-depleted antisera and precipitating antibodies. Studies on the antigenic structures of RCM-cobrotoxin revealed that RCM-cobrotoxin contains an immunodominant epitope at positions 22-38. The N-terminal and C-terminal regions of RCM-cobrotoxin encompass other epitopes which exhibit low reactivities toward anti-RCM-cobrotoxin antibodies. However, no precipitated antigen-antibody complexes were observed with the mixture of anti-RCM-cobrotoxin antibodies and RCM-cobrotoxin. These results suggest that the inherently different immunogenicities with different segments might affect the precipitabilities of the resulting antibodies, and that the notable immunogenecity of the C-terminal region is related to the production of precipitating and non-precipitating antibodies against cobrotoxin.

Amino Acid Sequence↗
PubMed2006

Fundamental features of copper ion precipitation using sulfide as a precipitant in a wastewater system.

We have investigated the precipitation features of copper ion using sulfide as a precipitant by varying the mole ratio of sulfide to copper ion, pH, temperature and the kind and concentration of complexing agent. In the precipitation of copper ion by sulfide, sludge is produced as cupric sulfide; thus, there is a possibility for its recycled use in photochemical and ceramic processes. When the ratio of the concentration of copper ion to sulfide was increased to more than 1.0, the extent of precipitation was very high. As the ratio was increased, nucleation time was decreased and crystal growth rate was raised. The higher the pH, the greater the amount of precipitated copper ion due to lowered solubility of cupric sulfide. When temperature changed from 25 degrees C to 55 degrees C, the precipitation of copper ion was increased a little. On the basis of estimated thermodynamic parameters such as Gibbs free energy and enthalpy, the precipitation reaction was spontaneous and endothermic. The precipitation of copper ion was lowered in the presence of complexing agent and it was affected by the stability of the copper complex. The feasibility test for the application of precipitation treatment to actual wastewater containing copper ion showed, although there was a little decrease in the removal of copper, the precipitation extent of copper was higher than 90% compared with that for artificial wastewater.

Chemical Precipitation↗
PubMed1984

Interaction of purified precipitating and non-precipitating (coprecipitating) antibodies with hapten and with haptenated protein. Evidence of an asymmetric antibody molecule.

The interaction of monovalent hapten dinitrophenyl epsilon-amino caproic acid (DNP-EACA) with purified IgG1 sheep anti-DNP precipitating and non-precipitating antibodies, and their F(ab')2, F(ab') and Fab fragments, was studied by fluorescence quenching and by a radioimmunoassay. The Scatchard plots of whole non-precipitating antibody and its F(ab')2 fragment showed a bi-modal curve that could be interpreted as due to the existence of two populations of sites with very different affinity for the ligand, each population representing 50% of the total number of sites. The F(ab) fragments of the non-precipitating antibody could be fractionated by immunoadsorption into two populations of high and low affinity whose association constants differed by more than 2 logs. The study of the interaction of whole antibodies with DNP-bovine serum albumin (BSA) demonstrated that each molecule of precipitating antibody can combine with two molecules of antigen but non-precipitating antibody cannot combine with more than one molecule of antigen. It is concluded that the molecule of non-precipitating antibody is asymmetric and has a site of high affinity and another of low affinity. As a consequence of this structure the non-precipitating antibody behaves functionally as univalent and is unable to form precipitates with the multivalent antigen and to activate effector mechanisms.

Aminocaproates↗
PubMed1986

Correlation of the character of intramolecular melting with digestibility by pepsin in precipitating and non-precipitating pig anti-Dnp antibodies.

Precipitating and non-precipitating pig anti-2,4-dinitrophenyl group (Dnp) antibodies were investigated by differential adiabatic scanning microcalorimetry in the pH range 3.7-4.5. The partial heat capacity functions obtained revealed a notable difference between the two antibody types when the analysis was done at pH 4.5 or 4.0. The transition observed at temps around 50 degrees C in a non-precipitating antibody was absent in a precipitating antibody. Under analogous conditions, pH 4.5, the precipitating antibody was fully resistant to pepsin, while the non-precipitating antibody yielded appropriate F(ab')2 and pFc'fragments. At pH 3.7 no substantial difference in the partial heat capacity function could be observed between the two antibody types. Below pH 4.0 the precipitating antibody became susceptible to peptic cleavage and yielded fragments of the same general character as the non-precipitating antibody. This finding lends support to the view that the structural block in immunoglobulin G that melts first, i.e. at temps near 50 degrees C, is the CH2 domain or a part of it.

2,4-Dinitrophenol↗
PubMed1954

Immunochemical studies of antitoxin produced in normal and allergic individuals hyperimmunized with diphtheria toxoid. IV. Differences between human precipitating and non-precipitating skin-sensitizing diphtheria antitoxin as shown by electrophoresis.

Electrophoresis on a starch-supporting medium was used to fractionate sera containing human diphtheria antitoxin of the following varieties (a) precipitating antitoxin, (b) non-precipitating skin-sensitizing antitoxin, and (c) mixtures containing precipitating and skin-sensitizing antitoxins. Aliquots of the protein fractions thus separated were tested for activity using the rabbit toxin neutralization test, precipitin techniques, and passive transfer tests in human skin. Non-precipitating, skin-sensitizing diphtheria antitoxin migrated largely as a fast moving gamma (gamma(1)) globulin. Passive transfer studies of isolated antitoxic fractions showed that they were as potent as whole serum in the ability to cause immediate wheal reactions. These fractions were not precipitable using appropriate quantities of purified toxoid. Precipitating diphtheria antitoxin migrated largely as a slow moving gamma (gamma(2)) globulin. Isolated antitoxic fractions of appropriate strength obtained from representative sera were precipitable by toxin and were unable to cause immediate wheal reactions upon toxoid challenge in human recipients. Mixtures of skin-sensitizing and precipitating antitoxins were separable by the technique of starch electrophoresis. The individual components removed from mixtures by this method retained the properties by which they could be characterized in whole serum.

Antibodies↗
PubMed1978

Determination of the position of electroimmune precipitates of antigen--antibody systems on their respective quantitative precipitation curves.

Using corresponding monospecific antisera from the rabbit, the precipitation curves for albumin, alpha-1-antitrypsin, haptoglobin 1-1 and fibrinogen were produced. In parallel, four different dilutions of these antigens were examined by line immmunoelectrophoresis, employing the same antisera. The distance of the resulting line immune precipitates from the start served to calculate the amount of antigen-antiserum reacting with each other. After converting these values to the amount of antiserum used for producing the precipitation curves, the 'line antigen/antibody ratios' were drawn into the appropriate precipitation curves. All electroimmune precipitates (in this case, the 'line immune precipitates') were found to be located on the side of antigen excess of their corresponding precipitation curve.

Animals↗
PubMed1986

IgG precipitating and non-precipitating antibodies in rabbits repeatedly injected with soluble and particulate antigens.

The immune response of precipitating antibodies and non-precipitating antibodies of high affinity (co-precipitating) of the IgG class was analyzed in rabbits repeatedly injected with egg albumin (as a soluble antigen) B. abortus-egg albumin and polymerized egg albumin (as particulate antigens). The results showed that the levels of anti-egg albumin non-precipitating antibodies induced by the soluble antigen were never higher than 10-15% of total antibodies throughout the experimental time. When particulate antigens were injected, the levels of non-precipitating antibodies increased up to 30-70% of the total antibody levels. This phenomenon is related to the way in which the antigen is available to the immune system (particle or aggregated), and is independent of the response induced by the particulate carrier. Components from the cell wall or bacterial membrane that could act as coadjuvants do not participate in this phenomenon. The results obtained seem to indicate that possibly there was a suppression of the synthesis of precipitating antibodies, and this would produce a relative increase in the non-precipitating antibodies.

Agglutination↗
PubMed1985

Protein precipitation induced by a textile dye. Precipitation of human plasminogen in the presence of Procion Red HE3B.

It was demonstrated that human purified plasminogen was precipitated in the presence of the textile dye Procion Red HE3B. The amount of precipitated plasminogen was dependent upon the molar ratio between the dye and protein and seemed to be independent of the protein concentration. A certain amount of dye was coprecipitated with the protein; this was shown also to be related to the dye-to-protein molar ratio. The precipitation of plasminogen induced by the dye was shown to have a pH optimum and to involve ionic and hydrophobic interactions. Procedures were devised which enabled the recovery of precipitated plasminogen in a soluble and non-denatured form totally free from dye. However, the precipitation of plasminogen by Procion Red HE3B could not be used as a single-step purification procedure from a heterogeneous starting material like plasma because of coprecipitation of other proteins. Nevertheless it is suggested that frequently there is a chance that a given protein will be precipitated by a given dye and therefore that protein precipitation by dyes could be a useful complementary method for the purification of proteins.

Aminocaproic Acid↗
PubMed1991

Precipitation of the renin inhibitor ditekiren upon i.v. infusion; in vitro studies and their relationship to in vivo precipitation in the cynomolgus monkey.

Ditekiren is a pseudo-octapeptide being developed as an inhibitor of human renin. Preclinical drug safety studies with this drug involved continuous i.v. infusions through indwelling catheters in the right internal jugular vein of the cynomolgus monkey for up to 30 days. The following physiocochemical properties of ditekiren make it susceptible to intravascular precipitation immediately following iv infusion: (1) the water solubility of ditekiren is high at acidic pH where the drug is formulated (pH 4) but low at physiologic pH, and (2) the water solubility of ditekiren decreases by roughly 50% from room temperature (25 degrees C) to physiologic temperature (37 degrees C). Studies of 28- and 30-day infusion durations revealed intravascular precipitation in monkeys using drug solutions and rates of infusion that were expected to be precipitation-free, based on the solubility of ditekiren and assumptions about blood flow in the monkey right internal jugular vein. Therefore, an in vitro apparatus was used to study the relationship among the drug concentration in the infusate, the rate of infusion, and the occurrence of precipitation in a fluid stream of phosphate-buffered bovine serum albumin solution (a facsimile of plasma). Maximum rates of infusion without precipitation were determined for a range of concentrations of drug in two separate formulations. Infusion conditions identified by the in vitro method as precipitation-free were then tried in a definitive 14-day monkey study. Of 24 monkeys infused with solutions of ditekiren, none showed evidence of intravascular precipitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1975

Precipitation of calcium phosphates from electrolyte solutions. III. Radiometric studies of the kinetics of precipitation and aging of calcium phosphates.

Precipitation and precipitate transformation in the system sodium phosphate (pre-adjusted to pH 7.4)--calcium chloride (25 degrees) was studied by means of radiometric analysis using 45Ca and 32P as tracers. Changes in the pH and the total concentrations of calcium and phosphate were followed during solid phase formation and the data were used to calculate composition changes of the precipitates and their supernatants. In all investigated systems two-step precipitation was observed, the precursor being more basic than the secondary precipitate. The composition of the latter was mostly within the range of the composition of octacalcium phosphate. The course of further chemical changes was dependent on the pH established during secondary precipitation. The heterogeneous exchange of the radionuclides between the solid phase and their supernatant solutions was also followed as a function of time. The results indicate that recrystallization through the mother liquid accompanied by composition changes is the dominant mechanism of equilibrium of the solid phases.

Apatites↗
PubMed1981

Evaluation of a new precipitation procedure for estimating high density lipoprotein cholesterol: precipitation of apolipoprotein B associated cholesterol with concanavalin A.

The implication of HDL as a negative risk factor in cardiovascular disease has focused on the need for an accurate but rapid routine method for determining HDL-cholesterol in human serum. A practical approach is the specific precipitation of apo-B-containing lipoproteins (atherogenic lipoproteins) by Concanavalin A (Con. A), a lectin with high affinity for glycoprotein apo-B. Specificity was assessed by radial immunodiffusion of apoprotein B in whole serum and in Con. A supernates. Double-immunodiffusion of isolated LP-fractions against anti-apo-B and Con. A demonstrated immunochemical identity of Con. A precipitable LP with apo-B-containing LP. Con. A precipitated cholesterol in the d : 1.063-1.21 g/ml fraction when apo-B was present. Complete precipitation of low density cholesterol was demonstrated, using a reconstituted serum sample radiolabelled in the d less than 1.063 g/ml fraction. Treatment of a reconstituted serum sample containing radiolabelled 125I-apo-A-I with Con. A demonstrated precipitation of trace amounts only of apo A-I. Con. A precipitated LP-B cholesterol quantitatively even when serum triglycerides (TG) exceeded 37.7 mmol/l. Clinical application of this method revealed that 73% of the patient population demonstrated apo-B in the d greater than 1.063 g/ml fraction.

Apolipoproteins↗