antigens

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слайд 1 antigens. microbial antigens. major histocompatibility complex. immunoglobulins the name antigens (gk. anti against, genos genus) is given to organic substances of a colloid structure (proteins and different protein complexes in combination with lipids or polysaccharides) which upon injection into the body are capable of causing the production of antibodies and reacting specifically with them. antigens, consequently, are characterized by the following main properties: (1) the ability to cause the production of antibodies (antigenicity), and (2) the ability to enter into an interaction with the corresponding antibodies (antigenic specificity). the features of molecules that determine antigenicity and immunogenicity are as follows. a. foreignness: in general, molecules recognized as "self” are not immunogenic; ie, we are tolerant to those self-molecules. to be immunogenic, molecules must be recognized as "nonself," ie, foreign. b. molecular size: the most potent immunogens are proteins with high molecular weights, ie, above 100,000. c. chemical-structural complexity: …

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sually small molecules, but some high-molecular-weight nucleic acids, lipids, complex carbohydrates and other substances are haptens as well. many drugs, eg, penicillins, are haptens, and the catechol in the plant oil that causes poison oak and poison ivy is a hapten. the addition of proteins to haptens even in a small amount gives them the properties of complete antigens. in this case the protein carries out the function of a conductor. vi o k h antigen structure of bacteria cell n h antigens of influenca virus isoantigens. isoantigens are those substances which have antigenic properties and are contained in some individuals of a given species. they have been found in the erythrocytes of animals and man. on the basis of antigenic structure the erythrocytes of all people can be subdivided into 4 groups. when the antigenic structures of the host are similar to those of the causative agent, the macroorganism …

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d may cause the production of antibodies which have a toxic effect on the corresponding cells. the origination of autoantigens is possible under the influence of cooling, radiation, drugs (amidopyrine, sulphonamides, preparations of gold, etc.), virus infections "(virus pneumonias and mononucleosis), bacterial proteins and toxins of streptococci, staphylococci, tubercle bacilli, paraproteins, aseptic autolysis of brain tissue, and other factors. collection of genes on chromosome 6 three regions: class i, class ii, class iii highly polymorphic! gene products: class i molecules class ii molecules class iii molecules (and other stuff) mhc complex major histocompatibility complex 20 class i mhc molecule class ii mhc molecule class ii mhc genes class i mhc genes class iii mhc genes 21 encoded by three loci: hla-a, hla-b, hla-c display antigens from within the cell (e.g., viral antigens) to cd8+ t cells. present on all nucleated cells! (good idea.) class i mhc molecules 22 encoded by …

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iation with class 1 mhc proteins. thus, a cytotoxic tcell that kills a virus-infected cell will not kill a cell infected with the same virus if the cell does not also express the appropriate class 1 proteins. mhc genes and proteins are also important in two other medical contexts. one is that many autoimmune diseases occur in people who carry certain mhc genes, and the other is that the success of organ transplants is, in large part, determined by the compatibility of the mhc genes of the donor and recipient. disease hla frequency of antigens at sick persons of presence at healthy persons antigens on which the immune answer develops addison’s disease dr5 70 20 adrenal cortex behtyer’s disease b27 89 9 unknown hashimoto’s thyreoiditis dr3, dr5 51 24 thyroglobulin juvenile diabetes dr3, dr4 72 24 insulin receptor rheumatoid arthritis dr7, dr21 59 21 colagen, fc fragment of igg narcolepsy …

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c enzyme such as papain, peptide bonds in the "hinge" region are broken, producing two identical fab fragments, which carry the antigen-binding sites, and one fc fragment, which is involved in placenta! transfer, complement fixation, attachment site for various cells, and other biologic activities igg. each igg molecule consists of two l chains and two h chains linked by disulfide bonds (molecular formula h2l2). because it has two identical antigen-binding sites, it is said to be divalent. igg is the predominant antibody in the secondary-response and constitutes an important defense against bacteria and viruses. igg is the only antibody to cross the placenta only its fc portion binds to receptors on the surface of placental cells. it is therefore the most abundant immunoglobulin in newborn. igg is one of the two immunoglobulins that can activate complement and opsonizes. immunoglobulin classes igm is the main immunoglobulin produced early in the primary …

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слайд 1 antigens. microbial antigens. major histocompatibility complex. immunoglobulins the name antigens (gk. anti against, genos genus) is given to organic substances of a colloid structure (proteins and different protein complexes in combination with lipids or polysaccharides) which upon injection into the body are capable of causing the production of antibodies and reacting specifically with them. antigens, consequently, are characterized by the following main properties: (1) the ability to cause the production of antibodies (antigenicity), and (2) the ability to enter into an interaction with the corresponding antibodies (antigenic specificity). the features of molecules that determine antigenicity and immunogenicity are as follows. a. foreignness: in general, molecules recognized as ...

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