The antigen used for coating the solid phase carrier can be divided into three major categories: natural antigen, recombinant antigen and synthetic polypeptide antigen. Natural antigens may be obtained from animal tissues, microbial cultures, etc., and must be extracted and purified for coating. For example, HBsAg can be extracted from the serum of the carrier. General bacterial and viral antigens can be extracted from the culture. Protein antigens can be extracted from materials rich in this antigen (eg AFP is extracted from cord blood or fetal liver). ). The recombinant antigen is a protein antigen expressed by an antigen gene in a plasmid, and most of them are Escherichia coli or yeast. The advantage of the recombinant antigen is that in addition to the engineering bacteria components, other impurities are less, and no contagious, but the purification technology is more difficult. Recombinant antigens using Escherichia coli as a plasmid may not be sufficiently used for ELISA, and may be used for ELISA, and false positives may occur in the reaction, since many subjects are infected with E. coli and anti-E. coli antibodies are present in the serum. Another feature of recombinant antigens is the ability to genetically engineer certain antigenic materials that cannot be separated from natural materials. For example, hepatitis C virus (HCV) has not been successfully cultured, and the HCV antigen content in the serum of patients with hepatitis C is extremely small. At present, most of the coated antigens used in the detection of anti-HCV ELISA are recombinant antigens prepared according to the gene expression of HCV. In the diagnosis of infectious diseases, many recombinant antigens such as HBsAg, HBeAg and HIV antigens have been used in ELISA. A synthetic polypeptide antigen is a polypeptide fragment artificially synthesized based on the amino acid sequence of an antigenic determinant of a protein antigen molecule. Polypeptide antigens generally contain only one antigenic determinant, which has high purity and high specificity. However, because the molecular weight is too small, it is often difficult to directly adsorb to the solid phase. The coating of the polypeptide antigen is generally first coupled to an unrelated protein such as bovine serum albumin (BSA) or the like, and indirectly bound to the surface of the solid support by adsorption of the conjugate to the solid support. Another point of attention in the application of the polypeptide antigen is that he can only detect antibodies corresponding thereto. A protein antigen often contains a number of different determinants that cause antibody production, so other antibodies in the serum to be tested cannot react with the polypeptide antigen. In addition, changes in antigen structure often occur when certain microorganisms are mutated. In this case, coating with individual polypeptide antigens may cause missed detection of other antibodies.
The antibody coated with the antibody-coated solid phase carrier should have high affinity and high specificity, and can be obtained from antiserum or monoclonal antibody-containing ascites or culture solution. If the antigen used in the immunization contains impurities (even in a very small amount), the hybrid antibody will appear in the antiserum and must be removed (absorbable method) before use in the ELISA to ensure the specificity of the test. Antiserum can not be used directly for coating, IgG should be extracted first, usually by ammonium sulfate salting and Sephadex gel filtration. Generally, crudely extracted IgG by ammonium sulfate salting has been used for coating, and highly purified IgG is unstable in nature. If high-affinity antibody coating is required to increase the sensitivity of the assay, affinity chromatography can be used to remove non-specific IgG from the antiserum. The concentration of monoclonal antibody in ascites is higher and the specificity is stronger. Therefore, absorption and affinity chromatography are not required. Generally, ascites can be directly diluted after appropriate dilution, and purified IgG can also be used if necessary. When applying monoclonal antibody coating, it should be noted that one monoclonal antibody is only directed to one antigenic determinant, and in some cases, mixed with a plurality of monoclonal antibodies can achieve better results.
[Composition]
The main component of this preparation is human immunoglobulin, which is prepared by cold ethanol fractionation of human plasma from healthy donors. The manufacturing process contains a step to remove anticomplementary activity and a dual viral inactivation process. It contains a suitable amount of glucose or maltose as stabilizer (see table below), but does not contain any antiseptic or antibiotic. The distribution of IgG subclasses is close to the serum level of normal subjects and maintains the bioactivity of Fc fragment of IgG.
[Indications]
1. Primary
agammaglobulinemia, such as X-linked hypogammaglobulinemia,
common variant immunodeficiency diseases, immunoglobulin G subclass deficiency,
etc.
2. Secondary
immunoglobulin deficiency diseases, such as severe infection, septicemia of
newborn, etc
Intravenous Injection Of Human Immunoglobulin
Intravenous Injection Of Human Immunoglobulin,Intravenous Immunoglobulin,High-Quality Effective Intravenous Immunoglobulin,Human Immunoglobulin For Intravenous Injection
Sichuan Yuanda Shuyang Pharmaceutical Co., Ltd. , https://www.syimmunoglobulin.com