U-2-Antigen-Antibody reaction.pptx inghhg ujut

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1. Antigen- Antibody Reaction Bhagyashree Mishra

2. ANTIBODY A RE ALSO KNOW AS IMMUNOGLOBULINS . All antibodies are immunoglobulins but all immunoglobulins are may or may not be a antibody. ANTIBODY Antibodies can be classified into five different classes; IgG, IgM, IgA, IgD, and IgE. All the antibodies have the basic four-chain antibody structure, but they have different heavy chains.

3. Antibody Structure

4. Applications of Antibodies The development of monoclonal antibodies has been used to treat several diseases like multiple sclerosis, rheumatoid arthritis, and different cancers. U sed to treat immune deficiencies as a means of passive immunity. Different classes of immunoglobulins can be used to analyze the antibody profile of patients. Antibodies can also be used as workhorse agents in biomedical research to study the workings of different antigens and their relationship with the host.

5. Immunoglobulin Structure Antibodies are globular plasma proteins with a basic Y-shaped structure and four polypeptides. There are two identical heavy chains and two identical light chains connected together by disulfide bonds. Each heavy chain is connected to a light chain by a disulfide bond, and the two heavy chains are connected to the light chains by two sulfide bonds. An antibody is composed of a variable region and a constant region. The variable region changes to various structures depending on the differences in the antigens. The constant regions are constant and do not change with antigens. Each light chain has one variable domain and one constant domain. The heavy chain, in turn, consists of one variable domain and three constant domains.

6. EPITOPE- The small site on an antigen to which a complementary antibody may specifically bind is called an epitope. PARATOPE- A paratope represents the specific site on an antibody within the variable region that directly interacts with the antigen. ANTIGENIC DETERMINANT- The antigenic determinants of a protein correspond to those parts of the molecule that are specifically recognized by the binding sites or paratopes of certain immunoglobulin molecules. Epitopes are thus relational entities that require complementary paratopes for their operational recognition.

7. General Characteristics of Ag-Ab Reaction Major Characteristics of Ag-Ab Reaction are as follows:- Specificity- Specific Ag binds to specific Ab, if any other its is Cross Reaction Entirety Whole of Ag and Ab molecule participate in specific reaction Denaturation Ag- Ab do not undergo any structural changes, or degrade. Surface combination Ag molecule present on the surface of the Ab molecule by non covalent bond, hydrophobic bond, Vander wall force etc. 5. Strength - Antibody Affinity Antibody Avidity 6. Valency

8. PRECIPITATION REACTION

9. AGGLUTINATION REACTIONS

10. COMPLIMENT FIXATION TEST

11. Definition- Complement fixation is one of the most important and one of the classical techniques for determining antigen-antibody complexes present in the testing sample. Complements are some special chemicals or protein components that are a part of our humoral immunity and aid in establishing antigen-antibody complexes, engulfing, degrading, and washing them away. They are found in the blood or attached near membranes. Eg. C1, C2, C3, C4 proteins, etc . The complement system is a collection of several proteins which interact with each other to initiate a series of reactions to assist in the defense of our immune system .

12. Positive test Antibody in sample + Antigen (added) + Complement    →  Ag-Ab Complex Fixed with Complement Complement fixed Ag-Ab + Indicator System     →   No change (No hemolysis)  Negative test Sample with no antibody + Antigen (added) + Complement    →   Free Complement Antigen (added) + Antibody in indicator system (On RBC)     →    Ag-Ab complex Ag-Ab complex + Complement  →  Fixed Complement System    →    Hemolysis

13. ENZYME LINKED IMMUNOSORBENT ASSAY

14. Q: What is a direct ELISA? Direct ELISA, or enzyme-linked immunosorbent assay, is a method for detecting and measuring a specific substance (analyte) in a sample. It's a quick and easy way to perform the assay, but it's less sensitive than other ELISA formats. Q: How it works ? C oat a microplate with the analyte Block the plate Add an enzyme-conjugated antibody specific to the analyte Add a substrate The substrate produces a signal that's proportional to the amount of analyte in the sample

15. Q: What is a In direct ELISA? An indirect ELISA (enzyme-linked immunosorbent assay) is a two-step test that detects antibodies in a sample. It's used to quantify immune responses . Q: How it works ? A plate is coated with an antigen. An unlabeled primary antibody binds to the antigen. An enzyme-conjugated secondary antibody binds to the primary antibody. A substrate is added, and the enzymes on the antibody produce a signal.

16. Q: What is a Sandwich ELISA? A sandwich ELISA is a laboratory technique that uses two antibodies to detect antigens in a sample. It's also known as a sandwich immunoassay. Q: How it works ? A capture antibody is attached to a solid surface. The sample containing the antigen is added to the plate. A detection antibody is added to the plate. A substrate is added to develop color.

17. Q: What is a In direct ELISA? Competitive ELISA is also known as an inhibition ELISA . It is a laboratory test that measures the amount of an antigen in a sample. It's used to detect the presence of antibodies in a sample, or to measure the concentration of an antigen Q: How it works ? A reference antigen is coated on a plate. A sample containing the antigen is added to the plate. The sample antigen competes with the reference antigen for binding to a labeled antibody. The amount of free antibodies that bind to the reference antigen is measured. The amount of antigen in the sample is determined based on the amount of free antibodies.

18. IMMUNOFLUOROSCENCE

19. What is it...... Immunoflourescence is a technique allowing the visualization of a specific antigen by binding a specific antibody chemically conjuagated with a fluorescent dye like FLUORESCENT ISOTHIOCYANATE (FITC) to detect and locate antigens in cells, tissues, or samples. It's often used in light microscopy, especially for microbiological samples .

20. Fluorescent is the property of certain molecule to absorb light at one wavelength and emit light at linger wavelength when it is illuminated by light of a different wavelength.

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