100 results about "Staphylococcal protein" patented technology

Embodiments concern methods and compositions for treating or preventing a bacterial infection, particularly infection by a Staphylococcus bacterium. Aspects include methods and compositions for providing a passive immune response against the bacteria. In certain embodiments, the methods and compositions involve an antibody that binds Staphylococcal protein A (SpA).

Provided are Staphylococcal protein A (SpA) variants for binding immunoglobulin (Ig), comprising a polypeptide which varies by one or more amino acids from the amino acid sequence of a natural variable heavy chain III (“VH3”) Ig-Fab binding region (“binding region”) of SpA, wherein the polypeptide exhibits a different binding specificity for Ig-Fab than does SpA or exhibits a different binding specificity for a non-Ig target molecule than does SpA. Further provided are methods of making the variants and methods of using the variants for in purification of Ig as well as diagnostic and therapeutic intervention.

The invention relates to a preparation method and application of an electrochemical immunosensor for a biomarker, namely a recombinant proprotein convertase subtilisin kexin type 9 (pcsk9) protein for predicting and diagnosing cardiovascular diseases, and belongs to the technical field of electrochemical detection. The preparation method is characterized by comprising the following steps: firstly, performing nitrogen doping on a graphene nanobelt (n-gnrs), performing amination on a fullerene-palladium-platinum nanoparticle (n-C60/pdpt) composite material and a staphylococcus aureus a protein (spa), and performing layer-by-layer self-assembling so as to immobilize a pcsk9 antibody (ab1); mixing the synthesized nanoparticle-poly-methylene blue (pt-pmb) with the pcsk9 antibody (ab2), and preparing a nano beacon, thereby obtaining the electrochemical immunosensor for pcsk9 protein detection. The electrochemical immunosensor has the advantages of being high in sensitivity, good in specificity and rapid and convenient in detection. A novel method for pcsk9 protein detection is provided, and useful information is provided for clinical prediction and diagnosis on cardiovascular diseases.

The invention provides a protein A immunoadsorption material which eliminates pathogenic antibody and the compound from plasma and the a preparation method. The invention discloses a polymer material coupled by agarose gel and staphylococcal protein A (SPA) and the material takes the agarose gel as vector matrix and takes polyamines reagent as a space arm, then reacting with glutaraldehyde and finally coupling with the protein A and blocking, reducing a double bond after being activated by epoxy bromopropane. The product has the high safety; by making use of the produce, the pathogenic antibody, more particularly, the immune compound pathogenic antibody can be effectively and selectively eliminated from the plasma of patients; and the invention can be applied to clinical immunoadsorption treatments.

A polypeptide is provided, which has a binding affinity for HER2 and which is related to a domain of staphylococcal protein A (SPA) in that the sequence of the polypeptide corresponds to the sequence of the SPA domain having from 1 to about 20 substitution mutations. Nucleic acid encoding the polypeptide, as well as expression vector and host cell for expressing the nucleic acid, are also provided. Also provided is the use of such a polypeptide as a medicament, and as a targeting agent for directing substances conjugated thereto to cells overexpressing HER2. Methods, and kits for performing the methods, are also provided, which methods and kits rely on the binding of the polypeptide to HER2.

The present invention relates to preparation of protein, especially the immune detection and amplifying system for preparing coupling agent and its preparation and application. The present invention is one kind of immune signal amplifying system including the compound of staphylococcal protein A (SPA) and streptomycin antibiotic. The system has high detection sensitivity, short operation time.

A chemical luminous ligand analysis method for quantitatively checking human antibodies belongs to the biomedical technical field, which comprises: using the generality that staphylococcal protein A (SPA) can react with Fc point of IgG in mice; using the monoclonal antibody of high affinity and specificity to prepare a standard product to establish a standard curve; respectively reacting the monoclonal antibody and the antibody in the sample with enzyme-labeled antigens; using the nanometer magnetic particles coated by SPA as ligand to separate solid and liquid; and using enzymatic chemical illumination reaction catalyzed by horseradish peroxidase (HRP) to process illumination check; thereby establishing a chemical luminous ligand quantitative analysis on human antibodies. The chemical luminous ligand analysis method is suitable for quantitatively checking all human antibodies, for resolving the problem of prior art while most human antibodies can not be accurately and quantitatively checked, avoiding cross reaction and avoiding false negative result or false positive result.

The invention relates to a staphylococcal protein A (SPA) immunoadsorption material used for blood purification and a preparation method thereof. The invention discloses a macromolecule material which is coupled by agarose gel and SPA. The material is prepared by taking the agarose gel as carrier substrate which is reacted with epoxy bromopropane to obtain the epoxy-based active carrier; after that, polyamines reagent is taken as a space arm which is then reacted with carbonyl diimidazole and is then coupled with the SPA. The material has the advantages of short synthesis time, safe preparation, strong specificity of product, high adsorption efficiency and good regeneration performance to immunoglobulin and the compound thereof, and being able to be applied to clinic immunoadsorption cure.

The invention relates to colloidal gold test paper for rapidly detecting an antibody of a porcine reproductive and respiratory syndrome virus (PRRSV). The test paper is characterized in that: the test paper is composed of a sample pad, a combination pad, a nitrocellulose membrane and an absorption pad which are sequentially attached to a nonabsorbent supporting sheet, wherein the combination pad is covered by PRRSVNsp9 proteins marked by colloidal gold; and the nitrocellulose membrane is respectively covered by a detection line T line composed of staphylococcus proteins A (SPA) and a quality control line C line composed of PRRSVNsp9 monoclonal antibodies 2D6. According to the invention, by utilizing an immunological principle that antigens and antibodies can be specially combined, the antigen marked by the colloidal gold is combined with the corresponding antibody and the conjugate of the antigen and the antibody is combined with the SPA to form an antigen-antibody-SPA conjugate, so as to form a color reaction on the nitrocellulose membrane (NC membrane) to be observed by naked eyes. The test paper provided by the invention has the characteristics of simplicity, fastness, sensitivity, good specificity and the like. And the price is low, so that the test paper is applicable to basically or clinically detecting the antibody of the porcine reproductive and respiratory syndrome virus. The test paper has the obvious advantages of strong specificity, high flexibility, simplicity in operation and fastness in diagnosis, and can be used for rapidly diagnosing the porcine reproductive and respiratory syndrome virus.

The present invention discloses a performance improved recombination staphylococcus aureus protein A affinity ligand and a construction method thereof. The present invention adopts a molecular biology method. A sequence B of a nature protein A is selected for molecular transformation. A C-terminal of the sequence B is added with two cysteines, so that the protein A can pass through double-locus coupled chromatography matrix to stabilize the connection. Six glycines are added to the end of a second Loop of the sequence B to increase the length and reduce the binding force with an antibody, so that elution conditions are mild. On this basis, resistance performance to high concentration base of the protein A is transformed. Asparagines and phenylalanine at 23rd and 30th positions of the sequence B are respectively replaced by threonine and alanine to obtain a sequence Z with higher alkaline resistance properties. Then, isocaudarner is used for connecting sequence Zs of different numbers head-to-tail in series. The efficient expression system of e. coli is used for overexpression. The expressed recombination protein A is coupled to agarose matrix preparation affinity chromatography fillers and is used for purifying antibodies. Results show that the recombination protein A affinity ligand prepared by the present invention is good in elution performance and alkali resistance.

The present invention concerns methods and compositions for treating or preventing a bacterial infection, particularly infection by a Staphylococcus bacterium. The invention provides methods and compositions for providing a passive immune response against the bacteria. In certain embodiments, the methods and compositions involve an antibody, such as a recombinant antibody, that binds IsdA and/or IsdB polypeptides.

The present invention relates to a classical swine fever antibody PPA-ELISA detection kit and a preparation method thereof. The kit preparation comprises: adopting RT-PCR to amplify a 550 bp gene fragment of E2 gene, wherein the fragment contains 4 neutralizing antigen regions of A, B, C and D; cloning the amplified 550 bp gene fragment into a pMD18-T vector; carrying out identification, wherein the identification result is correct; further directionally cloning the fragment into a PGEX-6P-1 prokaryotic expression vector; transforming BL21 expression bacterial; carrying out IPTG induced expression to obtain recombinant protein expressed in a form of inclusion body; adopting an affinity chromatography method to separate and purify the recombinant protein; adopting immunoblotting to detect antigenicity and specificity of the purified protein; and adopting the recombinant protein as coating antigen, adopting horseradish peroxidase-labeled staphylococcal protein A (SPA) as second antibody, optimizing reaction conditions of indirect ELISA, establishing an indirect ELISA detection method for detection of classical swine fever virus antibody, and assembling the classical swine fever antibody PPA-ELISA detection kit.

The invention discloses a surface-enhanced Raman gold-labeled test paper strip for quickly detecting trace fipronil and a preparation method thereof. A bottom layer of the test paper strip is a support layer, a middle layer of the test paper strip is an adsorption layer, a protection layer is fixed on the adsorption layer, and the adsorption layer sequentially comprises an absorption fibrous layer, a surface-enhanced Raman colloidal gold-labeled antibody fibrous layer, a cellulose membrane layer and a water absorption material layer of a handle end from a test end, wherein the cellulose membrane is coated with fipronil-coupled carrier protein to serve as a detection line and is also provided with a quality control line printed by goat or rabbit anti-mouse IgG (Immunoglobulin G), goat anti-rabbit IgG antibody or SPA (Staphylococcal Protein A). The test paper strip disclosed by the invention is prepared on the basis of a competitive mode, and target objects on a sample and the detectionline are competitively combined with the surface-enhanced Raman colloidal gold-labeled antibody. Tests show that the test paper has stronger specificity and higher sensitivity, the visual detection limit is an ng level, the quantitative detection limit of a Raman instrument is a pg level, and the test paper has no cross reaction with other pesticides or veterinary drugs.

The invention discloses an affinity chromatography medium, and a preparation method and an application thereof. The affinity chromatography medium provided by the invention comprises a solid phase carrier and recombinant staphylococcal protein A coupled with the solid phase carrier. The amino acid sequence of the recombinant staphylococcal protein A is represented by SEQ ID NO:1. The affinity chromatography medium provided by the invention has the advantages of high protein binding specificity, high affinity and high purification efficiency. The affinity chromatography medium can be used for separation and purification of protein.

This invention discloses to a kind of immunofluorescence mark reagent box. It is a reagent box applied for the aspects of immunity mark which uses the green fluorescence protein (GFP) as the indicator, the staphylococcus protein A (SPA) as the antibody. It also discloses the preparation method of the reagent. This invention can applied wide range in the field such as the immunity fluorescence mark, immunity histochemistry, biochemistry analysis, antibody test, protein chip and so on. It can replace the exist product efficiently, its operation is more simple, stability, delicacy and reliability, it is especially the same with the high flux analysis which analyze by the fluorescence analysis instrument.

The invention relates to a colloidal gold testing paper card used for detecting rabies virus antibodies of dogs and cats. By simultaneously coating a rabies virus-associated antigen strip and a staphylococcal protein A (SPA) antibody strip on a nitrocellulose membrane, and labeling the SPA by adopting colloidal gold, a universal testing paper card is obtained. The rabies virus antibodies in serums of the dogs and the cats are detected by using an immunochromatography principle so as to fulfill an aim of detecting the rabies virus antibodies of the dogs and the cats. The testing paper card overcomes the shortages of complicated and cumbersome operation, long testing time, requirement on instruments and incapability of detecting the antibodies in different animals by using the same testing paper card in the prior detecting art.