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PubMed1975

Multiple antigenic sites on an eicosapeptide. I. Precipitin studies in the goat.

Purified peptide 105-124, an antigenic determinant from the carboxy terminus ribonuclease, was found to form an immune precipitate with antibody to that region prepared by affinity chromatography from goat hyperimmune antiserum to reduced carboxymethylated ribonuclease (CM-RNase). Cm-rnase also gave an immune precipitate with the antibody. Purified antibody to another region of similar size (40-61) did not form a precipitate with CM-RNase but did co-precipitate in the presence of antibody to peptide 105-124 and CM-RNase. The precipitin reaction between antibody to peptide 105-124 and CM-RNase was inhibited by two synthetic derivatives, peptides 118-124 and ala114-RNase 114-124. Stoichiometry of the precipitin reactions of antibody to 105-124 with CM-RNase or peptide 105-124 suggested an antigen valency of three or more. Consistent with this both peptides 105-124 and ala114-RNase 114-124 elicited immediate cutaneous reactions but 118-124 did not. These findings suggest that the eicosapeptide 105-124 is multivalent since at least three antibodies can react simultaneously with it.

Animals↗
PubMed1978

A micro-procedure for quantitative precipitin tests.

A new method for the quantitative analysis of antigens and antibodies has been based on (1) ultrafiltration of the antigen-antibody precipitates through silver membranes of 0.2 micrometer pore size in a specially designed multisample apparatus, and (2) spectrophotometric determination at 210 nm of the amount of proteins in the antigen-antibody precipitates dissolved in 0.01 N HCl. At this wavelength, the = C = O group of the polypeptide chains constitutes the main chromophoric group. In comparisons with the ninhydrin color reaction, protein determination by low UV spectrophotometry, e.g., at 210 nm, was shown to be about 6 times more sensitive, permitting analysis of samples containing from 1.0 to 35.0 microgram of antigen. The concentration range of protein solutions in 0.01 N HCl which is measured at low UV can be regulated by a factor of 8--10 by changing absorption between 200 and 230 nm. Comparison of the ultrafiltration microtechnique with the standard quantitative precipitin microtechnique involving centrifugation of precipitates was made in 4 different antigen-antibody systems. The new technique was found to be as accurate as the standard technique. It allows completion of analysis within only 5--6 h. The standard precipitin technique, by contrast, requires a 5--7-day reaction period for completion.

Animals↗
PubMed1989

A comparison of competitive enzyme immunoassay and precipitin inhibition tests in the analysis of polysaccharide antigenic determinants of oral streptococci.

A rapid and convenient method of competitive enzyme immunoassay (EIA) was explored for the immunological analysis by MAbs of polysaccharide antigens prepared from the mutans group of streptococci, and optimal conditions for it were established. These included the concentrations of antigen, monoclonal antibodies (MAbs) and labelled antibody, temperature, pH and reaction time. The results were compared with those obtained by precipitin inhibition tests using the classical quantitative precipitin reaction, and they were found to be consistent with the latter method. It was concluded that the EIA system can be extended to the immunological study of polysaccharide antigens of oral streptococci using MAbs which perform poorly in precipitation reactions.

Animals↗
PubMed1977

A cellulose acetate membrane precipitin (CAP) test for amoebiasis.

A simple precipitin test (CAP) using cellulose acetate membrane has been devised and evaluated against the gel diffusion precipitin (GDP) test. In 251 sera tested by both methods, the CAP was never negative when the GDP was positive (110 sera). 34 sera were negative by the GDP but positive by the CAP; in all of these the patients either had a past history of amoebiasis or were considered to have active amoebiasis. The CAP is technically very simple, the result is available within four and a half hours, and the membranes can be impregnated with antigen and stored for several months. The CAP is slightly more sensitive than the GDP and remains positive longer after the patient has been cured; it seems to be equally specific.

Amebiasis↗
PubMed1984

Two monoclonal antibodies to two different epitopes of human growth hormone form a precipitin line when counterdiffused as soluble immune complexes.

We have tested whether soluble immune complexes obtained by mixing human growth hormone (hGH) with one anti-hGH monoclonal antibody (MAb) can form a precipitin line when diffused against another MAb in a polyethylene glycol containing gel. By testing seven anti-hGH MAbs one against the other in this assay, we have found that 10 pairs of MAbs out of the 21 possible combinations formed a line. Apparently, the first MAb formed soluble hGH dimers that were linked by the second MAb into precipitating linear complexes. Since each precipitin line was formed by the cooperative reaction of two MAbs, this sequential reaction of MAbs may be used in methods for the positive selection of MAbs that are suitable for two-site immunoassays.

Antibodies, Monoclonal↗
PubMed1987

Detection of protein variation in human serum by externally released precipitins from the blue crab, Callinectes sapidus.

1. A number of invertebrate species releases precipitins into the environment. This process is apparently part of an externally directed immunologic system. 2. A saline solution of precipitins released from the blue crab, Callinectes sapidus, provided a reagent that produced two different precipitation reactions with proteins from the sera of human individuals. 3. One of the reaction variants was also detected with mammalian antiserum, the other was not. The former variant was associated with a medical condition: hypergammaglobulinemia. 4. Saline reagents from different invertebrate species may prove useful in clinical diagnosis and for revealing new human protein polymorphisms.

Animals↗
PubMed1975

Quantitative precipitin studies on the specificity of an extract from Tridacna maxima (Röding).

Haemolymph from the clam Tridacna maxima precipitated with purified H-blood-group substances, Helix pomatia galactogen, and pneumococcus type XIV polysaccharide. Although gel diffusion, gel electrophoresis, and inhibition experiments indicated that only a single precipitating lectin was present in the haemolymph, quantitative precipitin and haemagglutination results suggested that a second agglutinin with anti-H-like specificity was also present. Evidence obtained from hapten inhibition experiments indicated that the precipitin that reacts with pneumococcus type XIV polysaccharide can be inhibited by a number of simple sugars. Of the compounds tested, 2-acetamido-2-deoxy-D-galactose was the best inhibitor of precipitation with pneumococcus type XIV polysaccharide and of haemagglutination with human erythrocytes, but the inhibition experiments showed that the extract was also markedly inhibited by D-galactosamine hydrochloride, D-galactose, lactose, and p-nitrophenyl beta-D-galactopyranoside. The latter compound was more active than its parent sugar, which was in turn a more potent inhibitor than p-nitrophenyl alpha-D-galactopyranoside. Melibiose, raffinose, and stachyose, compounds which each contain terminal alpha-linked D-galactopyranosyl residues, were relatively weak inhibitors. The combining sites of the lectin that reacts with pneumococcus type XIV polysaccharide appear, therefore, to be most complementary to 2-acetamido-2-deoxy-D-galactopyranosyl residues, probably in beta linkage.

Animals↗
PubMed1958

A comparison of human antisera to purified diphtheria toxoid with antisera to other purified antigens by quantitative precipitin and gel diffusion techniques.

The limits of sensitivity of three gel diffusion methods are compared and their utilization in the detection of small amounts of antibody to antigens present in traces in a preparation is illustrated with the diphtheria toxin-human antitoxin system. The Preer modification of the Oakley-Fulthorpe technique and the Oudin tube method were found more sensitive than the Ouchteriony plate method, and permitted the detection of as little as 3 microg. antibody N/ml. of serum. Antisera from eight Schick-negative individuals immunized with purified diphtheria toxoid have all been shown to contain, in addition to antitoxin, antibodies to substances present as impurities in the purified toxoid injected. The amounts of these antibodies in a serum and a partial characterization of their antigen-antibody curves have been determined through the combined use of quantitative precipitin and gel diffusion methods. Different amounts of antibody have been precipitated by toxin and toxoid from individual sera. Evidence is presented that this may have been due to slight differences in antigenic specificity. A serum, Hu, which had been held to contain no precipitating antibody, has now been shown, by the Preer and Oudin techniques, to contain at least 12 microg. of precipitating antibody N (per ml. serum) against an impurity in the toxoid preparation. This estimate has been confirmed by quantitative precipitin determinations. The presence of antibodies to impurities in all human antitoxins examined in the present work brings into question the assumption that human antitoxin as such has a skin-sensitizing capacity.

Antibodies↗
PubMed1959

The precipitin reaction between DNA and a serum factor in systemic lupus erythematosus.

The sera of certain patients with systemic lupus erythematosus contain an antibody-like substance capable of reacting with highly purified DNA preparations from widely divergent sources. Precipitin reactions have been demonstrated by double diffusion in agar and quantitative precipitin curves have been obtained. Complement was observed to be fixed in the reaction. Evidence was obtained that the serum factor possessed antigenic properties similar to those of gamma-globulins and migrated with this fraction on zone electrophoresis. The interaction of this factor with DNA exhibited certain specific characteristics which differ considerably from non-specific reactions between DNA and proteins in general. The DNA-precipitating factor appeared to be one of a number of related factors reacting with nuclear constituents of many different cells. It differed in certain respects from the "LE factor" which is responsible for the formation of "LE cells." The accumulated evidence, although not yet conclusive, favors the concept that the precipitating factor represents an antibody to DNA, and that it is one of a number of autoantibodies elicited in this disease.

Antibodies↗
PubMed1978

Increasing the predictive value positive of the precipitin test for the diagnosis of deep-seated candidiasis.

Three hundred fifty human sera were tested by double immunodiffusion, crossed-line electrophoresis, and crossed immuno-affinoelectrophoresis with a concanavalin A intermediate gel for precipitating antibodies to antigens present in cytoplasmic extracts of Candida albicans. Sera from 48 of 287 hospitalized patients at risk of invasive candidiasis contained precipitating antibodies to Candida antigens. Of these 48 sera, 27 had precipitating antibodies only to cell-wall antigens present in the cytoplasmic extract, and 21 sera had precipitating antibodies to both cytoplasmic and cell-wall antigens. The latter sera came from patients who were 2.5 times as likely to have deep-seated candidiasis as those patients with precipitins exclusively to cell-wall antigens. Sera from seven of 22 patients with vaginal candidiasis and 10 of 41 patients with other fungal infections had precipitating antibodies to C. albicans cell-wall antigens; only two of these sera also contained precipitating antibodies to the cytoplasmic antigens. Crossed immunoaffinoelectrophoresis with concanavalin A reduced the number of false-positive results and increased the predictive value positive of the precipitin test for deep-seated candidiasis from 31% to 71%.

Antigens, Fungal↗
PubMed2000

Application of the agar gel precipitin test to detect antibodies to Salmonella enterica serovar enteritidis in serum and egg yolks from infected hens.

Serological surveillance can be an important component for egg quality assurance programs geared toward controlling problems with Salmonella enterica serovar Enteritidis (S. enteritidis) within a flock. Serum is the primary sample source for the procedures, although egg yolk antibody assays have become popularity in recent years. However, these assays tend to be labor intensive, requiring procedures for extracting antibodies from the yolk followed by assaying the samples. We describe an adaptation of the agar gel precipitin (AGP) test for use in detecting antibodies to S. enteritidis deposited in egg yolks of infected hens. Yolk or sera from infected birds were administered to wells cut into seven-well clusters in an agar gel plate, and detection antigen was added to the center well. The agar gels were incubated for 24 h and then examined for the presence of precipitin lines formed by the interaction of antibody with antigen. Three different antigens were tested: S. enteritidis flagella, SEF14 (a 14-kDa fimbrial protein produced ostensibly by S. enteritidis), and a sodium deoxycholate extract of whole S. enteritidis organism. Flagella and the organism extract detected antibodies to S. enteritidis in the yolk and sera, whereas SEF14 was not reactive. Positive reactions were observed in serum 1 wk postchallenge, whereas in yolks, this was further delayed by 1 wk. The sensitivity of the test was slightly less than the standard microagglutination assay, although specificity was slightly higher, as indicated by results from sera and yolks from birds infected with Salmonella enterica serovar Typhimurium. Simplicity and low labor requirements of the assay would allow for the potential testing of several hundred egg samples within a day, which would make up for test shortcomings due to sensitivity. The AGP test could be an important tool for individuals using serological testing to monitor the S. enteritidis situation within their flocks or as a rapid screen for vaccine responses. The assay could also be used in tandem with other AGP tests to screen for the presence of multiple avian pathogens.

Animals↗
PubMed1978

Precipitins to different avaian serum antigens in bird fancier's lung and coeliac disease.

Precipitins to avian serum antigens have been found in the sera of bird fanciers and, until now, they have been considered strong supporting evidence for a clinical diagnosis of bird fancier's lung (BFL). We now report that 35% of patients with coeliac disease, none of whom had recently kept a bird, had precipitins against an avian serum antigen common to all the avian species tested, but which was distinct from the antigens usually associated with BFL. This antigen was a component of hen egg yolk but not of bird droppings. In patients with BFL the antibody response results from inhaled antigens in the bird droppings, whereas the antibody response in patients with coeliac disease probably results from eating uncooked or soft-boiled eggs.

Adult↗
PubMed1984

A general theory for the precipitin reaction--based on Fc-mediated precipitation.

Fc-mediated immune precipitation is studied theoretically by computer simulation of precipitin curves and of zonal profiles of soluble immune complexes. Comparison with experiments indicates that Fc-mediated immune precipitation is caused by Fc-Fc interactions with association constants ranging from 10(5) to 10(7) liters/mole. The Langmuir adsorption isotherm is used for evaluation of these interactions. A general theory for the precipitin reaction is formulated, assuming it to be a three-stage process: 1st stage Formation of immune complexes, 2nd stage Precipitation due to coalescence of antibody-rich immune complexes, and 3rd stage Fc-mediated immune precipitation.

Antigen-Antibody Complex↗
PubMed1983

Evaluation of a gel diffusion precipitin test for porcine parvovirus.

The use of a gel diffusion precipitin (GDP) test for the detection of porcine parvovirus (PPV) infection in pigs is described. The close correlation between gel diffusion precipitin and haemagglutination inhibiting (HI) antibody titres indicates that, with careful standardisation, a high level of sensitivity can be achieved with the GDP test and that it is a simple and relatively inexpensive alternative to the more commonly used HI test. Experimental infection of 2 groups of pigs showed that GDP and HI antibody responses were closely correlated and that GDP antibodies to PPV persisted for at least 41 weeks after infection. In a commercial herd study, serological evidence of declining passive immunity and subsequent acquisition of active immunity was demonstrated by measuring the GDP and HI antibody titres in sequential serum samples of pigs from a known PPV endemic farm. The GDP test described was shown to be less sensitive than haemagglutination (HA) in the detection of viral antigen but was, nevertheless, considered useful as a simple screening test for the amounts of antigen usually present in PPV infected mummified foetuses.

Animals↗
PubMed1983

Evaluation of surface components of Brucella ovis as antigens for the detection of precipitin antibody in serums from artificially exposed rams.

Surface components of Brucella ovis obtained by gentle physical shearing were tested as a potentially useful source of reagent for selective serological diagnosis. These antigens were used in a radial immunodiffusion (RID) test against serum from rams which had been inoculated with infective semen containing B. ovis by one of 4 routes namely mating rams with ewes previously inoculated intravaginally with infective semen, or by direct inoculation in the prepuce, rectum or nasal passage. Loosely attached surface antigens in the RID test formed precipitin bands with serums collected from rams 2 and 10 weeks after inoculation. In contrast, a detergent extracted membrane antigen B developed precipitin bands only with serum collected 10 weeks after inoculation from rams confirmed bacteriologically to be infected with B. ovis in the genital tract. The route by which the rams were artificially exposed did not affect the outcome of the RID test using the membrane B antigen. However, all experimentally exposed rams had demonstrable CF titres when a heat extracted antigen was used.

Animals↗
PubMed1973

Lectins in precipitin reactions with soluble H substance of human saliva and serum.

Lectins that precipitate the soluble H substances of saliva were produced for the first time from the four commonly used sources of seed. In Ouchterlony precipitin reactions, identity was observed between extracts of Cytisus sessilifolius and Laburnum alpinum, but these extracts displayed incomplete identity with extracts from Ulex europaeus. These three sources of the precipitating lectin formed bands when tested with saliva from all secretors and none with saliva from nonsecretors. Extracts from Lotus tetragonolobus, however, formed two bands with saliva from secretors and one strong band with all saliva from nonsecretors. This new antigen, which reacts with Lotus, is present in all saliva and on red cells of all normal individuals, but it is absent in the O(h) (Bombay) type. The lectins formed bands with serums of secretor and nonsecretor individuals, but these bands were weaker than those with saliva, and revealed incomplete identity between H substance of serum and saliva. The precipitin reaction of the lectins is an efficient method for demonstrating relations among lectins and among antigens and has led to the discovery of a new human antigen.

Antigens↗
PubMed1989

Development and characterization of a monoclonal antibody against the tube precipitin antigen of Coccidioides immitis.

Primary infection with Coccidioides immitis is commonly accompanied by the production of an immunoglobulin M precipitin antibody which is detected by the tube precipitin (TP) assay or by the immunodiffusion assay for TP antibody (IDTP assay). In the present investigation, spleen cells from spherulin-immunized BALB/c mice were fused with SP2/O Ag14 myeloma cells, and the resulting hybridomas were screened for antibody to the IDTP antigen by using an enzyme-linked immunosorbent assay. Positive hybridomas were cloned by limiting dilution and injected into pristane-primed mice for ascites production. Characterization of antibody reactivity was accomplished with the IDTP assay, two-dimensional immunoelectrophoresis, and immunoblotting. An immunoglobulin G1 monoclonal antibody which reacts with the IDTP antigen of C. immitis is described. The epitope that is recognized by the monoclonal antibody is also present, but to a lesser extent, on a second coccidioidal antigen which has been designated antigen 2. The monoclonal antibody was not reactive in immunoblots of histoplasmin or blastomycin, indicating that the epitope recognized by this antibody may be specific for C. immitis.

Animals↗