Interactions between precipitating and nonprecipitating antibodies in the formation of immune complexes

In the present study, we used monoclonal antidinitrophenol (DNP) antibodies to determine certain of the biophysical characteristics of precipitating and nonprecipitating antibodies. In addition, we studied the dynamics of immune complex (IC) formation when precipitating antibodies react with antigen in the presence of nonprecipitating antibodies. The antigen utilized in these studies was DNP-bovine serum albumin. All isolated nonprecipitating anti-DNP antibodies were of the IgG2b isotype, whereas all antibodies with other isotypes (IgG1, IgG3, IgM, IgA and IgE) were precipitating. Nonprecipitating antibodies did not differ significantly from precipitating antibodies in affinity, valence, or isoelectric point. Nonprecipitating antibodies inhibited the formation of precipitable IC between antigen and precipitating antibodies. In addition, preformed IC precipitates were solubilized by nonprecipitating antibodies. The solubilization of IC precipitates was influenced by the isotype of the precipitating antibody and by the antibody:antigen ratio in the IC precipitate. By isokinetic sucrose density centrifugation, we determined that solubilization of IC precipitates by nonprecipitating antibodies was associated with release of free precipitating antibody and formation of soluble IC between the antigen and the nonprecipitating antibody. In conclusion, in this study the nonprecipitating property of mouse anti-DNP antibodies is isotype-specific. Nonprecipitating antibodies compete and displace precipitating antibodies from the antigen, resulting in inhibition of IC precipitation and in IC solubilization. On the basis of the present results, we postulate that antibody-antibody interactions are important determinants of precipitating ability, and that these interactions are a characteristic of antibody isotype.     

Starch in fungi IV. The lipoprotein amylose-precipitating factor

The amylose precipitating factor from Neurospora is a lipoprotein of 53,800 mw. The lipid component, which is responsible for the amylose precipitating activity, is mainly polar lipid and constitutes 14.5% of the lipoprotein molecule. The binding of amylose to the amylose precipitating factor possibly results in the conversion of the amylose molecule from a random coil to an interrupted helix configuration.     

桔皮果胶提取条件的选择

用酸浸提、酒精沉淀法,从桔皮中提取果胶,通过正交设计分析,获得最佳得率的工艺条件。即果胶浸提液的酸度为pH2,反应时间2小时。沉淀果胶的酒精浓度为50％,其得率是12.6％。     

Toxocara canis: Some characteristics of larval precipitating antibodies in rat serum

1972. Toxocara canis: Some characteristics of larval precipitating antibodies in rat serum. International Journal for Parasitology 2: 471–479. Serum from rats infected with 1000 T. canis eggs had larval precipitating antibodies present at least between 21 and 183 days post infection. The precipitating antibodies in whole serum were stable to heating at 60°C for 1 h and excretory pore precipitates developed in serum treated with 2-mercaptoethanol.

Fractionation of serum on G-200 and DEAE-cellulose and analysis of the fractions by immunoelectrophoresis indicated the fraction containing fast 7S globulin was primarily responsible for precipitating activity. Purified precipitating antibodies were stable to heating at 70°C for 15 min.

No skin fixing antibodies were detected in immune sera employing both a homologous and heterologous PCA text.     

Dependence of diffusion coefficients and immunoprecipitating titers on pH: Human serum transferrin,immunoglobulin A,human chorionic somatomammotropin,and their rabbit antibodies

The “two-cross” technique, a new two-dimensional immunodiffusion technique, is applied to the study of immunosystems human serum transferrin: a preparation of rabbit antibodies, human serum immunoglobulin A-rabbit antiserum, and human chorionic somatomammotropin-rabbit antiserum. By using this technique it is possible to determine simultaneously the diffusion coefficients and the precipitating titers of the precipitating components and the immunochemical titers of antibody or antisera. The investigations were performed in 0.15 mol dm^?3 phosphate-buffered saline solutions in the pH range 5.0–8.6 in 1% (w/v) agarose gel at 20.0 ± 0.1°C. The results obtained for the diffusion coefficients and for the precipitating titers indicated that the reversible self-association of antigens and antibodies with the increasing pH of the medium is accompanied by the decreasing solubility of the precipitating components in the immunoprecipitating system. The changes in immunochemical titers with increasing pH were used to explain the changes in the antigen-to-antibody ratios at equivalency.     

Identification of proteases of staphylococci by means of an antitrypsin precipitating serum]

Specific antitrypsin precipitating sera obtained by intraconjunctival immunization of rabbits with crystalline trypsin was used to reveal in the supernant of staphylococcal cultures protease having antigenic character common with that of trypsin.This is confirmed by the trypsin accumulation in the process of staphylococcus cultivation, by the inhibition of the proteolytic activity of the antitrypsin precipitating sera and by the production of protein-precipitate as a result of incubation of the supernant with the antitrypsin precipitating sera.     

Activity,stability and enantioselectivity of lipase-coated microcrystals of inorganic salts in organic solvents

Lipase-coated microcrystals of inorganic salts were prepared by dissolving enzymes in buffers and then mixing with 3 volumes of saturated salt solutions followed by drop-wise addition into polar precipitating organic solvents. The Mucor javanicus lipase-coated microcrystals did not show any activity for esterification of lauric acid with 1-propanol in isooctane when NaCl and Na₂SO₄ were used as the salts but showed much higher activity than the enzyme powder when KCl (10.0 times) and K₂SO₄ (5.8 times) were used as the salts and precipitated in 1-propanol. Acetonitrile was found to be the best precipitating solvent for preparing M. javanicus lipase-coated microcrystals, with enzyme activities 26.2 and 22.4 times higher than that of the enzyme powder when KCl and K₂SO₄ were used as precipitating salts, respectively. The presence of water in the precipitating solvents markedly decreased the enzyme activity. The M. javanicus lipase-coated microcrystals prepared using K₂SO₄ as the salt and acetonitrile as the precipitating solvent was as active at 80°C as at 40°C. No significant improvement in enantioselectivity of Candida rugosa lipase-coated microcrystals was observed for transesterification of 1-phenylethanol with vinyl acetate in hexane when the microcrystals were prepared by dissolving the enzymes in salt solutions containing 25% (v/v) of acetone or 2-propanol before precipitating in polar solvents.     

Some Experiments with Salts of Heavy Metals as Fixatives

Heavy metal salts mostly in 0.5M concentration were used for tissue fixation and for albumin and gelatin precipitation. Tissues from dog, cat, and rabbit were stained in acid and basic stains. It was found that the atomic weight of the cation of the salt influenced its precipitating power. Penetration was either uniform or non-uniform and the resulting shrinkage generalized or cellular. Tissue hardening or high precipitating efficacy of a given salt did not always give good tissue preservation, but well preserved tissue was necessarily firm after fixation and fixed by a salt with a high precipitating efficacy. The mordanting effects of the fixatives were arbitrarily classified into three types: isomordants, basic mordants, and acid mordants.     

Precipitating and relieving factors of migraine versus tension type headache

ABSTRACT: BACKGROUND: To determine the differences of precipitating and relieving factors between migraine and tension type headache METHODS: This is a cross sectional study. We retrospectively reviewed the records of 250 migraine patients and 250 patients diagnosed as tension type headache from the specialized headache clinic in Dept. of Neurology, Dhaka Medical College Hospital. Data were collected through a predesigned questionnaire containing information on age, sex, social status and a predetermined list of precipitating and relieving factors. RESULTS: In this study, the female patients predominated (67%). Most of the patients were within 21--30 years age group (58.6%). About 58% of them belonged to middle class families. The common precipitating factors like stress, anxiety, activity, journey, reading, cold and warm were well distributed among both the migraine and tension type headache (TTH) patients. But significant difference was demonstrated for fatigue (p < 0.05), sleep deprivation (p < 0.05), sunlight (p < 0.01) and food (p < 0.05), which were common among migraineurs. In consideration of relieving factors of pain, different maneuvers were commonly tried by migraineurs and significant difference were observed for both analgesic drug and massage (p < 0.05), which relieved migraine headache. But maneuvers like sleep, rest and posture were used by both groups. CONCLUSION: The most frequent precipitating factors for headache appear to be identical for both migraine and TTH patients. Even though some factors like fatigue, sleep deprivation, sunlight and food significantly precipitate migraine and drug, massage are effective maneuver for relieving pain among migrianeurs.     

Production and characterization of monoclonal antibodies to group-specific antigenic determinant of group A streptococcal polysaccharides

Hybridomas producing monoclonal antibodies (McAb) to group A streptococcal polysaccharide (A-PS) were obtained. Of these, 3 clones were selected: 2 clones producing IgG3, precipitating McAb and 1 clone producing IgM nonprecipitating McAb. The results of the competitive inhibition in the enzyme immunoassay suggested that precipitating and nonprecipitating McAb reacted with nonidentical epitopes of A-PS, though determinants, specifically reacting with the given McAb, had a common site which included N-acetyl-D-glucosamine. On the surface of bacteria, in addition to protein M, the presence of the given determinants of A-PS was established in the direct immunofluorescence test. The newly developed method of direct immunofluorescence with the use of specially selected precipitating McAb was the basis for the development of rapid diagnosticum, permitting the identification of group A streptococci.     

Prolixase, a fibrinolytic enzyme isolated from Rhodnius prolixus (Heteroptera, Reduviidae): antigenic properties

Antigenic properties of prolixase are studied showing that this fibrinolytic enzyme, induces in the rabbit, the formation of precipitating but slightly, hemagglutinating homologous antibodies.     

光谱法研究甲醇和盐酸对短梗霉黑色素的分离效果

应用紫外和红外光谱对甲醇和盐酸分离的短梗霉黑色素进行了分析。分析结果表明:甲醇和盐酸法分离的黑色素在紫外图谱215 nm处都有最大吸收峰,而甲醇法分离的黑色素其紫外图谱在260、280 nm处无吸收峰表明此法分离的黑色素不含核酸及蛋白质;红外图谱中,在3340 cm-1、1637 cm-1处有很强的吸收峰表现为黑色素的典型特征;同时在对照中发现盐酸多次处理后的黑色素显示较少的结构信息,说明盐酸沉降法有可能破坏黑色素的结构。由此选用甲醇作为沉淀剂有利于黑色素的纯化及确保其结构信息的完整,为进一步分析短梗霉黑色素的结构表征奠定了基础。     

Crystallization and preliminary x-ray diffraction studies of recombinant rabbit interferon-gamma

Two different crystal forms of recombinant rabbit IFN-gamma were obtained under different crystallization conditions. The first, a tetragonal form with space group P43212 or P41212, was obtained through vapor phase equilibration using the sitting drop rods technique with ammonium citrate as the major precipitating agent. The unit cell dimensions of this crystal form are a = b = 82.1 A and C = 116.3 A. These crystals diffract to 2.8 A resolution and contain a dimer in the asymmetric unit. A second crystal form was obtained by the batch method at pH 8.0 using sodium chloride as the precipitating agent. The crystals are hexagonal, space group P6122 or P6522, and with unit cell dimensions of a = b = 58.0 A and c = 169 A. This form contains monomer in the asymmetric unit and diffracts to greater than 2.7 A resolution. Both forms appear to be eminently suitable for further analyses and crystal structure solution.     

The kinetics of protein precipitation by different reagents

The kinetics of precipitation of soya protein has been examined in a tubular flow reactor with the precipitants, ammonium sulfate, ethanol, divalent calcium, and sulfuric acid. The precipitate growth profiles obtained in all cases showed the rapid formation of a precipitate phase and the attainment of a final size within 16 s. The final mean particle diameter d(m) varied with precipitating agent used in the order: sulfuric acid (12.5 mum) > ethanol (7.5 mum) approximately calcium ion (7.2 mum) > ammonium sulfate (3.1 mum). In the case of ethanol precipitation, changes in the design of the contacting section of the reactor led to differences in the precipitate growth curve. Protein solubility curves are also presented, and with the reactor data, they provide a convenient method for assessing the effect of precipitating agent on the design of protein precipitation reactors.     

Precipitating antibody against protease of Corynebacterium pyogenes in pigs.

Antibody in sera from pigs carrying an abscess associated with Corynebacterium pyogenes and healthy pigs was examined by the agar gel diffusion test. In the test, the concentrated culture fluid containing the protease of C. pyogenes was used as antigen. As a result, precipitating antibody was demonstrated in sera from 25 of 30 abscessed pigs and a few of the healthy pigs. When the relationship between precipitating antibody and protease was examined by the immunoelectrophoresis and gel filtration of the concentrated culture fluid, the antibody was shown in the same position as the protease. From the result, it was clear that the precipitating antibody was against the protease of C. pyogenes. All the proteases produced by 27 strains of C. pyogenes of porcine and bovine origin were serologically identical with one another. They were, however, serologically different from those of Staphylococcus aureus, Bacillus cereus, and B. subtilis. In the inhibition test, the proteolytic activity of C. pyogenes was inhibited by the serum of the abscessed pig. It was also inhibited by healthy pig serum. From the results, it seems that the determination of precipitating antibody may be useful for the diagnosis of C. pyogenes infection.     

Binding and precipitating activities of Lotus tetragonolobus isolectins with L-fucosyl oligosaccharides. Formation of unique homogeneous cross-linked lattices observed by electron microscopy

We have recently observed that certain asparagine-linked oligosaccharides are multivalent and capable of binding and precipitating with the D-mannose-specific lectin concanavalin A [cf. Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726] and with a variety of D-galactose-specific lectins [Bhattacharyya, L., Haraldsson, M., & Brewer, C. F. (1988) Biochemistry 27, 1034-1041]. In the present study, we have examined the binding and precipitating activities of a variety of mono- and biantennary L-fucosyl oligosaccharides with three L-fucose-specific isolectins from Lotus tetragonolobus, LTL-A, LTL-B, and LTL-C. The results show that certain difucosyl biantennary oligosaccharides are capable of cross-linking and precipitating with tetrameric isolectins, LTL-A and LTL-C, but not with dimeric isolectin, LTL-B. Quantitative precipitation analyses show that biantennary oligosaccharides containing the Lewis(x) antigen (or type 2 chain of Lewis(a)), Gal beta (1-4)[Fuc alpha (1-3)]GlcNAc, at the nonreducing terminus of each arm are bivalent ligands. However, a biantennary oligosaccharide containing a Lewis(x) determinant on one arm and a type 2 chain of blood group H(O) determinant, Fuc alpha (1-2)Gal beta (1-4)GlcNAc, on the other arm and a monoantennary oligosaccharide containing two fucose residues (analogue of the Lewis(y) antigen) bind but do not precipitate with the isolectins, indicating that the positions and linkage of fucose residues are critical for cross-linking.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroid Storm—A Review of Cases at University of California,San Francisco

Retrospective study of the diagnosis and management of the 8 cases of thyroid storm in a series of 400 hyperthyroid patients led to conclusion that thyroid storm is a clinical diagnosis based on a life-endangering illness in a hyperthyroid patient whose hyperthyroidism has been severely exacerbated by a serious precipitating illness, and that storm is manifest by the symptoms of hyperpyrexia, tachycardia and striking alterations in consciousness. No laboratory tests were diagnostic of storm, and the underlying precipitating cause of thyroid storm was the major determinant of survival. Vigorous therapy must include blocking synthesis of thyroid hormones with antithyroid drugs, blocking release of preformed hormone with iodine, meticulous attention to hydration and supportive therapy, as well as correction of precipitating cause of storm. The blocking of the sympathetic nervous system with reserpine or guanethidine or with alpha and beta blocking drugs may be exceedingly hazardous and requires skillful management and constant monitoring in a critically ill patient.     

A simple approach to DOTAP and its analogs bearing different fatty acids

A simple synthesis of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl sulfate (DOTAP) and its analogs differing in the fatty acids is presented. The synthesis is designed as quasi-one-pot reaction and the precipitating products are purified by simple recrystallization.     

Fluorescence detection of organic molecules in the Jovian atmosphere

A search for fluorescent emission due to the presence of possible organic molecules in the Jovian atmosphere is described. We first consider natural Jovian fluorescent emission excited by precipitating auroral particles. Due to our lack of knowledge of the Jovian precipitating particle energies and fluxes we nest consider fluorescent emission excited by a laser system aboard a Jupiter spacecraft. Laser-induced fluorescence is routinely used to monitor trace constituents and pollutants in the terrestrial atmosphere. Several spacecraft laser systems are currently under development. Our calculations indicate that laser-induced fluorescent detection is approximately two orders of magnitude more sensitive than rocket ultraviolet measurements of possible Jovian absorption features at 2600 Å that have been attributed to the presence of adenine or benzene.     

Attempts to rationalize protein crystallization using relative crystallizability

Protein crystal growth (PCG) remains the bottleneck of crystallography despite many decades of study. The nucleation zone in the two-dimensional-phase diagram has been used to evaluate the relative crystallizability of proteins, which is expressed as a percentage over the phase area delineated by experimental protein and precipitating agent concentration ranges. For protein-salts which are subject to a direct temperature effect on solubility, as represented by Egg Lysozyme, a decrease in temperature augments the nucleation zone percentage whereas for those with retrograde solubility as a function of temperature, for example fructose-1,6-bisphosphatase in the presence and absence of AMP, an increase in temperature can significantly enhance the relative crystallizability. These results have been confirmed by the number of "hits" using PEGs as precipitating agents in Sparse Matrix Screen experiments for different proteins and are in excellent agreement with the relative crystallizability. The relationship between solubility dependence, relative crystallizability and crystallization success, has been evidenced. Such crystallizability can become a guide to identify efficient crystallization regions, providing a rational approach to PCG and structural biology.