Antibody PPT BTTTT.pptx

6

1. Group 2 Wajjiha Amjad 1378-FBAS/BSBT/F20 Ayesha Ishtiaq 1383-FBAS/BSBT/F20 Sheeza Arif 1386-FBAS/BSBT/F20 Shabana Noor 1399-FBAS/BSBT/F20 Submitted to: Dr. Sadaf Submission date: October 18, 2022

2. A protein made by plasma cells (a type of white blood cell) in response to an antigen (a substance that causes the body to make a specific immune response). Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen . anti- "against" + body . Antibody:

3. Structure of Antibody Each antibody consists of four polypeptides– two heavy chains and two light chains joined to form a "Y" shaped molecule. The amino acid sequence in the tips of the "Y" varies greatly among different antibodies. This variable region, composed of 110 -130 amino acids, give the antibody its specificity for binding antigen. The variable region includes the ends of the light and heavy chains.

4. Treating the antibody with a protease can cleave this region, producing Fab or fragment antigen binding that include the variable ends of an antibody. The constant region determines the mechanism used to destroy antigen. The variable region is further subdivided into hypervariable (HV) and framework (FR) regions. Hypervariable regions have a high ratio of different amino acids in a given position, relative to the most common amino acid in that position.

5. Within light and heavy chains, three hypervariable regions exist – HV 1, 2 and 3. Four FR regions which have more stable amino acids sequences separate the HV regions. The HV regions directly contact a portion of the antigen's surface hence called complementarity determining regions, or CDRs . The FR regions form a beta-sheet structure which serves as a scaffold to hold the HV regions in position to contact antigen.

6. There are millions of antigen/epitope. Our immune system has the ability to produce specific antibody against specific antigens. This diversification in antibody is known as antibody diversity. There are variety of pathogens entering in our body so we should have huge collection of antibody . Two process that produce diversity and variety to the antibody genes take place in germinal cell through B cell maturation .

7. Somatic cells contains a relatively small number of Ig genes. Somatic hyper-mutation means mutation is very active at this variable region. At V region variation take place. Variable region of Ig chains is encoded by multiple gene segments. These segments arrange to form a functional variable region exons. Somatic Hyper-mutation

8. A process by which B cells randomly assemble Ig gene segments to form functional variable region exon. Process occurs at the early development of lymphocytes. Two types of recombination occurs one in V region and one in C region. Recombination in C region gives the idea of what kind of antibody will produce . VDJ Recombination

9. Recombination takes place in heavy and light chains. The V ( variable) region of L chain is coded by a one of the V J recombinant. V region of H chain is coded by a one of the VDJ recombinant. The C (Constant) region of both H & L chain is coded by one of the C region of gene. In human there are 51Vh segments, 27Dh segments, 6Jh segments and series of C region .

10. V region is coded by 3 type of gene segments: V D & J segments. V D J gene segments encode the variable domain of IG heavy chain. During B cell maturation and somatic cell recombination randomly selected D and J segments join and intervening DNA is discarded. Next randomly selected V segment and DJ rearranged segment joins and again intervening DNA is discarded. VDJ recombination – heavy chain gene family

11. Heavy chain then reassembled to make Ig that is unique to particular B cell and will fight against specific antigen. Recombination in C region gives the idea of what kind of antibody will produce. The region present after V region antibody will name after it . M D G E A V D J Variable Region Constant Region µ &   γ   E α

12. No recombination , B cell keep producing Ig M. Ig M is most dominant form. First type of antibody produced when B cell is not specific and don’t know specific antigens. Ig loci has multiple gene segments and these can be rearranged in many possible ways combination. This leads to antibody diversity.

13. Polyclonal And Monoclonal Antibodies

14. Classification of antibodies is by the means in which they are created from lymphocytes. The antibodies can be classified into two primary types: Monoclonal Antibodies: Polyclonal Antibodies:

15. Monoclonal Antibodies: Monoclonal Antibodies are generated by identical B-cells which are clones from a single parent cell. mAbs have the monovalent affinity and only recognize the same epitope of an antigen. Polyclonal Antibodies: Polyclonal Antibodies are the antibodies usually produced by different B-cell clones in the body. pAbs can bind to many epitopes of a single antigen .

16. Key Differences Between Polyclonal and Monoclonal Antibodies

17. Polyclonal Antibodies (pAbs) Monoclonal Antibodies (mAbs) Produced by different clones of plasma B-cells. A heterogeneous antibody population Produced by a single clone of plasma B-cells. A homogeneous antibody population. 1 . 2. 3. M ixture of immunoglobulin that are secreted against a particular antigen . A population of antibodies that are produced by a single clone of plasma B-cells.

18. Polyclonal Antibodies (pAbs) Monoclonal Antibodies (mAbs) Tolerant of small changes in protien structure. Interact with different epitopes on the same antigen. Intolerant to changes in protein structure. Interact with a particular epitope on the antigen. 4. 5. 6 . Production doest not required hybridoma cell lines. Production requires hybridoma cell lines.

19. Conclusions Conclusively, For applications such as therapeutic drug development that require large volumes of identical antibody specific to a single epitope, monoclonal antibodies are a better solution. For general research applications, however, the advantages of polyclonal antibodies typically outweigh the few advantages that monoclonal antibodies provide. With affinity purification of serum against small antigen targets, the advantages of polyclonal antibodies are further extended.