Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Immunoprecipitation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

Synthesis of LH-RH by rat hypothalamic tissue in vitro: I. Use of a specific antibody to LH-RH for immunoprecipitation.

Following the procedure of Jeffcoate et al. [1974] we have successfully obtained a specific antiserum to LH-RH in rabbits, and are utilizing our antibody to study the synthesis of LH-RH by rat hypothalamic tissues in vitro. Our antibody, used at a dilution of 1:20,000, binds 37% of added 125I-labelled LH-RH, and cross-reacts minimally with thyrotropin releasing factor (TRF; 4.0%), somatotropin release inhibiting factor (SRIF; 0.035%), and melanocyte inhibiting factor (MIF; 0.009%). The antiserum recovers LH-RH added to charcoal-stripped rat serum quantitatively. Serial dilutions of rat hypothalamic extract and varying aliquots of normal rat serum are parallel to the standard curve (synthetic LH-RH: 0-100 pg/tube). Hypothalamic tissue of 4 male rats, bounded by the optic chiasm, mammillary bodies and hypothalamic fissures to a depth of 2-3 mm, was pooled, minced and incubated for 1-3 h in 2 ml of Eagle's Minimum Essential Medium in atmosphere of 95% O2/5% CO2 with 10 muCi of 3H-glycine. Reactions were stopped by the addition of 1 ml 0.1 N HC1. The tissue and medium were homogenized together and boiled for 3 min. Aliquots from the incubates were neutralized, LH-RH levels measured by radioimmunoassay (RIA), and 3H-glycine incorporation determined by immunoprecipitation, using our antibody. 3H-glycine incorporation into presumptive LH-RH increased linearly over the 3 h period. Aliquots of the 3 h incubates were chromatographed on Sephadex G-25 columns (1 x 10 cm) using 0.01 M acetic acid for elution; 1 ml fractions were collected. Synthetic LH-RH was chromatographed in a similar manner, and its elution profile determined by UV absorbance at 280 mm. Aliquots of each fraction of the eluted material from the 3 h incubates were counted in a scintillation counter to determine the elution pattern of the labelled material. Additionally, aliquots from the 1 ml fractions were neutralized and used for immunoprecipitation. Coincident peaks of 3H-label, immunoprecipitable 3H-labelled presumptive LH-RH, and synthetic LH-RH were observed. These results lend strong evidence to support our conclusion that the technique of immunoprecipitation is an efficacious approach to the study of the synthesis of LH-RH by rat hypothalamic tissue in vitro.

Animals↗
PubMed1979

Improved method for the specific immunoprecipitation of albumin.

The immunoprecipitates of many antigens are frequently contaminated by coprecipitation of unrelated substances. A method to overcome this type of contamination in the immunoprecipitation of albumin is described. The insoluble albumin-antibody complexes are solubilized by a brief treatment at high temperature in the presence of sodium dodecyl sulfate, and after dilution the mixture is submitted to a second immunoprecipitation.

Animals↗
PubMed1976

The use of immunoprecipitation to study the synthesis and cleavage processing of viral proteins.

Several factors have been considered in developing an immunoprecipitation procedure which minimizes the background of non-immunospecifically precipitated protein. The procedure evolved utilizes the technique of direct immunoprecipitation (specific antibody plus sufficient unlabeled antigen to form a precipitable complex). High speed centrifugation of the cell extract immediately prior to immunoprecipitation and the use of test tubes coated with silicone greatly reduced background precipitation.

Animals↗
PubMed1979

Improvements in immunoprecipitation of specific messenger RNA. Isolation of highly purified conalbumin mRNA in high yield.

We have described previously procedures for the isolation of specific mRNA employing immunoprecipitation of polysomes. In spite of our success with ovalbumin mRNA in the chicken oviduct, we have had considerable difficulties in applying these same published techniques to the immunopurification of conalbumin mRNA, despite the fact that the chicken oviduct synthesizes up to 10% of protein as conalbumin. Here we describe a number of modifications and refinements which have proved essential in obtaining intact conalbumin mRNA in high purity and high yields. These refinements include: (a) improved purification of conalbumin in order to remove contaminating proteins that result in impure antibodies; (b) improved isolation of specific conalbumin antibody in high yields; (c) improved methods for reducing contamination by non-specific polysomes; (d) improved techniques for isolation of RNA from immunoprecipitates resulting in less degradation and higher recovery of conalbumin mRNA; (E) improved techniques for efficient translation of conalbumin mRNA involving treatment of the RNA with methylmercury prior to translation. We conclude that problems involved in the immunoprecipitation of different mRNAs may differ, and that various refinements in techniques may be required for obtaining highly purified preparations of intact mRNA in high yields.

Animals↗
PubMed1979

Adenovirus type 2 early polypeptides immunoprecipitated by antisera to five lines of adenovirus-transformed rat cells.

We have identified adenovirus type 2 (Ad2)-induced early polypeptides (EPs) and have attempted to determine which EPs are coded by each of the four early gene blocks. [35S]methionine-labeled EPs were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cycloheximide pretreatment followed by labeling in hypertonic medium (210 to 250 mM NaCl) facilitated the detection of EPs. Seven major (reproducible bands in autoradiograms) EPs were detected with molecular weights of 74,000 (74K), 21K, 19K, 15K, 13.5K, 11.5K, and 11K. Minor (weaker bands) EPs of 55K, 52K, 42K, 18K, 12K, 8.8K, and 8.3K were also often seen. To identify and map the genes for virus-coded EPs, we prepared antisera against five lines of adenovirus-transformed cells that retain different fractions of the viral genome. The lines were F17, 8617, F4, and T2C4 transformed by Ad2 virions and 5RK (clone I) transformed by transfection with the Ad5 HsuI-G fragment (map position 0 to 8). The early gene blocks retained and expressed (in part) as RNA in these cells were as follows: 5RK(I), block 1 (70% of left 8% of genome); F17, block 1; 8617, blocks 1 and 4; F4 blocks 1, 2, and 4; T2C4, blocks 1, 2, 3, and 4. The following major EPs were immunoprecipitated: 15K by all antisera; 53K and 14.5K by F17, T2C4, 8617, and F4 antisera; 11.5K by T2C4, 8617, and F4 antisera; 44K, 42K, 19K, and 13.5K by T2C4 antisera; 11K by 8617 antisera. Minor EPs of 28K, 18K, and 12K were precipitated by all antisera except 5RK(I). The 53K and 15K EPs were precipitated also from Ad2 early infected monkey cells by the F17 antiserum and by sera from hamsters bearing tumors induced by Ad1-simian virus 40. The relationships between some of the immunoprecipitated EPs were investigated by the partial proteolysis procedure. All 53K EPs are the "same" (i.e., highly related), all 15K EPs are the "same," and all 11.5K EPs are the "same." The 15K EP is highly related to the 14.5 K EP. Although less certain, all 28K EPs appeared related, as did all 18K EPs. The T2C4-specific 44K EP is probably a dimer of the 21K glycopolypeptide. The T2C4-specific 13.5K EP and the 8617-specific 11K EP appear unrelated to any other polypeptides. These immunoprecipitation data provide evidence that early gene block I (map position 1 to 11) may encode major 53K, 15K, and 14.5K polypeptides, and minor 28K, 18K, and 12K polypeptides, and that all or some of the gene for 15K and 14.5K lies within map position 1 to 8. The surprisingly complex pattern of polypeptides coded by early gene block I raises the possibility that some polypeptides may be coded by overlapping "spliced" mRNA's. The possible block locations of the genes for the 21K, 13.5K, and 11.5K polypeptides are discussed.

Adenoviruses, Human↗
PubMedDate not supplied

Relevance of the immunoprecipitation assay to human immunogenicity of influenza vaccines.

Influenza vaccines representing each of the four U.S. manufacturers' output for the 1975-76 respiratory season were characterized clinically and assayed by immunoprecipitation. All vaccines contained 350 CCA units/dose each of the A/Port Chalmers/1/73 (H3N2) and A/Scotland/840/74 (H3N2) viruses plus 550 CCA units/dose of B/HK/5/72 virus. Two of the vaccines were whole virus while the other two were subunit products; one made by extraction with ethyl ether, the second by detergent treatment. The vaccines were compared for serologic efficacy in children naturally primed to the (H3N2) family of viruses and by immunoprecipitation techniques against monospecific goat antiserum to the viral hemagglutinin prepared at the Bureau of Biologics of the U.S. Food & Drug Administration. The subunit vaccines had significantly greater specific activity (human immunogenicity/unit mass of type-specific precipitable antigen) than the whole virus products. It is concluded that clinical immunogenicity is as much a function of antigen form (subunit vs whole virus) as it is of mass and that setting a level for precipitable antigen content alone is an insufficient criterion for potency standardization. Since antigen form, as well as mass, must be considered, immunoprecipitation may be useful for standardization of human immunogenicity only if candidate lots are compared by this technique to an homologous, reference vaccine of identical manufacture and form which is tested for potency in humans.

Antibodies, Viral↗
PubMed2024

Phage Immunoprecipitation and Sequencing-a Versatile Technique for Mapping the Antibody Reactome.

Characterizing the antibody reactome for circulating antibodies provide insight into pathogen exposure, allergies, and autoimmune diseases. This is important for biomarker discovery, clinical diagnosis, and prognosis of disease progression, as well as population-level insights into the immune system. The emerging technology phage display immunoprecipitation and sequencing (PhIP-seq) is a high-throughput method for identifying antigens/epitopes of the antibody reactome. In PhIP-seq, libraries with sequences of defined lengths and overlapping segments are bioinformatically designed using naturally occurring proteins and cloned into phage genomes to be displayed on the surface. These libraries are used in immunoprecipitation experiments of circulating antibodies. This can be done with parallel samples from multiple sources, and the DNA inserts from the bound phages are barcoded and subjected to next-generation sequencing for hit determination. PhIP-seq is a powerful technique for characterizing the antibody reactome that has undergone rapid advances in recent years. In this review, we comprehensively describe the history of PhIP-seq and discuss recent advances in library design and applications.

Humans↗
PubMed1975

Immunodiagnosis of human schistosomiasis using different immunoprecipitation techniques.

One hundred sera of individuals infected with Schistosoma mansoni and/or S. haematobium were examined for the presence of specific anti Schistosoma antibodies by means of different immunoprecipitation techniques: immunoelectrophoresis, immunodiffusion, immunoelectroosmophoresis (on two different supports), and electroimmunodiffusion. The immunoelectroosmophoresis proved to be superior to the other immunoprecipitation techniques, its main advantages being sensitivity, rapidity, and economic use of reagents. Precipitins against the antigen of the intermediate host, Biomphalaria glabrata, were demonstrated in 66% of the sera.

Antibodies↗
PubMed1979

Immunoprecipitation of biosynthetically-labelled products in the identification of antigens of murine red cells infected with the protozoan parasite, Plasmodium berghei.

In this methodological paper an immunoprecipitation technique has been optimised for the identification of antigens of Plasmodium berghei-infected blood which react with antibody specificities in a host-protective antiserum. Extracted 3H-leucine biosynthetically-labelled products of infected blood were sequentially reacted and precipitated with sera from mice which had been exposed to P. berghei but which were either non-protected or protected against lethal infection, protection having been shown to be transferable to naive recipients with the appropriate serum. As analysed by polyacrylamide gel electrophoresis under reducing conditions, a small number of molecular species was detected in immunoprecipitates using host-protective sera which were apparently not quantitatively precipitated out of the complex mixture of labelled products of infected blood using sera from non-protected mice.

Animals↗
PubMed1978

Filtration and immunoprecipitation in the elimination of DNA polymerase activity associated with bacterial contamination of sera positive for hepatitis B e antigen and its corresponding antibody.

Samples of serum inoculated with Escherichia coli and serum that became contaminated with bacteria after exposure to a laboratory atmosphere demonstrated elevated DNA polymerase activity. The levels of activity were well within the range of values found in hepatitis B e antigen (HBeAg)-positive samples. The bacterial polymerase activity was markedly reduced by a single passage of serum samples through a 0.22-micron Millipore filter prior to analysis. Repeated filtration did not result in a substantial further decrease in polymerase activity. In sera that were heavily contamined with E. coli, however, filtration was not successful in reducing bacteria-associated polymerase activity to a base-line uncontaminated level. In such instances double antibody immunoprecipitation proved effective in elimination of bacterial activity. When bacterial contamination of serum samples is a possibility, specimens should be subjected to either Millipore filtration or immunoprecipitation prior to analysis, particularly when correlation of DNA polymerase activity with HBeAg and its corresponding antibody is attempted.

Antibodies, Viral↗
PubMed1977

Subfractionation of rat liver microsomes by immunoprecipitation and immunoadsorption methods.

Rabbit antisera were prepared against cytochrome b5 and NADPH-cytochrome c reductase [EC 1.6.2.4] purified from rat liver microsomes, and utilized in examining the distribution of these and other membrane-bound enzymes among the vesicles of rat liver microsomal preparations by immunoprecipitation and immunoadsorption methods. Smooth microsomes with an average vesicular size of 200 nm (diameter) and sonicated smooth microsomes with an average diameter of 40-60 nm were used in subfractionation experiments. Immunoprecipitation of microsomal vesicles with anti-cytochrome b5 immunoglobulin failed to show any separation of the microsomes into fractions having different enzyme compositions. Cytochrome b5 was apparently distributed among all vesicles even when sonicated microsomes were used. When the antibody against NADPH-cytochrome c reductase was used, however, immunoadsorption of microsomes on Sepharose-bound antibody produced some separation of NADPH-cytochrome c reductase and cytochrome P-450 from NADH-cytochrome b5 reductase and cytochrome b5. The separation was more pronounced when sonicated microsomes were used. These results indicate microheterogeneity of the microsomal membrane, and suggest the clustering of NADPH-cytochrome c reductase and cytochrome P-450 molecules in the membrane.

Absorption↗
PubMed1977

Purification of immunuglobulin light chain messenger RNA by immunoprecipitation from mouse myeloma tumor, MOPC-31C.

Polysomes producing IgGl(kappa) myeloma protein were specifically selected by an immunoprecipitation method, and immunoglobulin light chain mRNA was purified from the precipitated polysomes. The purified mRNA migrated predominantly as a single band and the molecular weight of this mRNA was calculated to be 410.000 by polyacrylamide gel electrophoresis in 98% formamide. A protein possessing a molecular weight of 25,000, which is the size of the light chain precursor, was synthesized as a major product of translation in a wheat germ cell-free system. DNA complementary to the mRNA (cDNA) was prepared with avian myeloblastosis virus RNA-dependent DNA polymerase. This cDNA had an average size of 8.3S as determined by sedimentation through an alkaline sucrose gradient. Using this cDNA, Crt 1/2 values of template RNA and RNA from various preparations were calculated from the results of molecular hybridization. The relative content of the mRNA increased 4,4-fold during the immunoprecipitation of polysomes.

Animals↗
PubMed1978

Immunoprecipitation of a cytoplasmic precursor of rat-liver cytochrome oxidase.

A simple method for the isolation of rat liver cells is described. The cells are shown, by an isotope dilution method, to maintain a constant rate of protein synthesis for 8 h of incubation. Antibodies to purified rat liver cytochrome oxidase were raised in rabbits and used to investigate the labeling of cytochrome oxidase in isolated rat liver cells and in vivo. The data demonstrate the occurrence of a precursor of the subunits of cytochrome oxidase that are synthesized in the cytoplasm. 1. Dodecylsulfate gel electrophoresis of the immunoprecipitates from isolated rat liver cells that had been labeled with [35S]methionine for 1 h showed a single radioactive peak with a molecular weight of 50000. 2. Judged by the effects of cycloheximide and chloramphenicol the labeled protein is synthesized on cytoplasmic ribosomes. 3. After labeling for 1 h in vivo with [3H]leucine the labeled protein appears to be exclusively associated with the hepatic microsomal fraction. 4. Ouchterlony double-diffusion analysis demonstrated immunological relationship between the precipitates from microsomes and cytochrome oxidase. In addition to the precipitates derived from mitochondria and microsomes immunoprecipitates were also obtained from the cytosol in comparable amounts; these again were immunologically related. The occurrence of large amounts of precursor(s) (or degradation products) of cytochrome oxidase in rat liver fractions is interpreted in terms of a regulatory pool for amino acid homeostasis in the organism.

Animals↗
PubMed1975

Identification of the in vitro translation products of adenovirus mRNA by immunoprecipitation.

Adenovirus type 2 mRNA was translated in S30 extracts from Ehrlich ascites and wheat embryo cells. The in vitro products were identified by sodium dodecyl sulfate-gel electrophoresis after immunoprecipitation with specific antisera in the presence of urea. Seven virion polypeptides could be identified by immunoprecipitation. Three of these appear to be precursors to polypeptides of the virion. mRNA isolated late in adenovirus infection was separated into three size classes by zonal sedimentation. Material sedimenting at 26S was translated into polypeptides corresponding to the largest virion polypeptides II to IV, a 22S fraction corresponding to polypeptide V, and smaller polypeptides and a 15S fraction corresponding to polypeptide IX. A significant amount of polypeptide IX was also synthesized by the 26S and 22S RNA.

Adenoviridae↗
PubMed1979

Human cytomegalovirus-induced immediate early antigens: analysis in sodium dodecyl sulfate-polyacrylamide gel electrophoresis after immunoprecipitation.

Immediate early antigen (IEA) induced in human lung fibroblasts by human cytomegalovirus was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis after immunoprecipitation with IEA-positive human sera. Two polypeptides of 76,000 daltons (76K) and 82K were detectable within 90 min after infection. Polypeptides of similar molecular weight were also found in immunoprecipitates of human cytomegalovirus-infected cells nonpermissive for virus replication. IEA is located within the nucleus, although some of the 76K material appears to be located on the outer nuclear membrane. Raising salt concentrations in the extraction buffer increased antigen extraction. The contribution of these IEA polypeptides to IEA nuclear fluorescent staining is discussed.

Animals↗
PubMed1976

Yeast cytochrome c messenger RNA. In vitro translation and specific immunoprecipitation of the CYC1 gene product.

An assay based upon indirect immunoprecipitation has been developed for yeast cytochrome c and apocytochrome c. The specificity of this assay was demonstrated by its ability to selectively precipitate cytochrome c from an autolysate of yeast cell proteins. Translation of the polypeptide chain of cytochrome c in a wheat germ extract programmed with yeast poly(A) RNA was demonstrated using this immunoprecipitation assay. Translation of poly(A) RNA from yeast strains carrying nonsense mutations in the cyc1 gene yielded in vitro cytochrome c polypeptides which were shorter than the wild type protein by the amount expected for polypeptide chains which had terminated at the nonsense codon. The in vivo rate of cytochrome c synthesis was shown to be 6-fold greater in derepressed cells than in glucose-repressed cells. The 6-fold difference is sufficient to account for the 6-fold higher level of cytochrome c in derepressed than in repressed cells. The level of translatable cytochrome c mRNA is at least 4 times as high in derepressed as in glucose-repressed cells, suggesting that regulation occurs at some step in the synthesis of this messenger.

Cytochrome c Group↗
PubMed1978

[Indirect immunoprecipitation by rat liver polyribosomes using antibodies to tyrosine aminotransferase].

A fraction of rat liver polyribosomes is isolated, which in its immunochemical characteristics considerably enriched with polyribosomes capable to synthesize hydrocortisone-induced liver tyrosine aminotransferase isoenzyme. This specific polyribosome fraction was purified by immunochemical fractionation of total liver polyribosomes using indirect precipitation. The content of polyribosomes in immunoprecipitates comprise 0.4-0.8% of its initial amount (before immunochemical fractionation). The ratio of specific polyribosomes in immunoprecipitates varies from 20 to 45%, which corresponds to 25-100-fold purification. The data obtained suggest that the method of indirect precipitation can be an efficient step in the isolation procedure of individual mRNA.

Animals↗
PubMed1977

[Direct immunological identification of proteins following electrophoretic separation in polyacrylamide micro-gradient gels and the effect of detergents on immunoprecipitation (author's transl)].

Methods for direct immunological identification of single protein components after fractionation of a protein mixture in microgels are described. Protein mixtures were separated with high resolution in polyacrylamide microgradient gels and transferred after electrophoresis into agarose layers containing suitable antisera. Monospecific as well as polyvalent antisera were used. The formation of immunoprecipitates could be observed within approx. 1 h. Immunoprecipitates are also formed in the presence of sodium dodecylsulfate or other detergents, thus allowing immunoreactions to be performed with water-insoluble proteins. Staining of the proteins in the gels did not completely inhibit the immunoreaction, while dansylation of proteins had no effect. The influence of different detergents e.g. sodium dodecylsulfate, Triton X-100, Brij 99, np-40 and urea, as well as different reducing agents e.g. mercaptoethanol, dithiothreitol, thioglycolic acid, on two-dimensional microdiffusion was also studied. When suitable concentrations of these compounds were used, the formation of immunocomplexes was observed within approx. 1 h. This technique can also be applied to immunoreactions with water-insoluble proteins dissolved in detergents.

Blood Proteins↗