Monoclonal Antibodies

1. MONOCLONALantibodies Dr.T.V.Rao MD Dr.T.V.Rao MD

2. Beginning of Monoclonal Era • Georg Kohler and Cesar Milsteinfuse mouse lymphocytes with neoplastic mouse plasma cells to yield hybridomas that produce specific antibodies. This offers a limitless supply of monoclonal antibodies. Monoclonal antibodies permit diagnostic tests that are specific, and function as probes. Dr.T.V.Rao MD

3. Discovery of Monoclonal Antibodies • Monoclonal antibodies were produced in mice using a technique described by Köhler and Milstein et al.. They were awarded the Nobel Prize in 1984 (along with Jerne) for their work. Dr.T.V.Rao MD

4. Nobel prize in Medicine and Physiology wasawarded toKöhler, MilsteinandJerne in 1984 Dr.T.V.Rao MD

5. Monoclonal Antibodies • Monoclonal antibodies are Monospecific antibodies that are identical because they are produced by one type of immune cell that are all clones of a single parent cell. Given (almost) any substance, it is possible to create monoclonal antibodies that specifically bind to that substance Dr.T.V.Rao MD

6. Nomenclature • The nomenclature of monoclonal antibodies is a naming scheme for assigning generic, or non-proprietary, names to a group of medicines called monoclonal antibodies. This scheme is used for both the World Health Organization’s International Non-proprietary Names and the United States Adopted Names Dr.T.V.Rao MD

7. Study of Myeloma leads to Discovery of Monoclonal antibodies • In the 1970’s the B-cell cancer myeloma was known, and it was understood that these cancerous B-cells all produce a single type of antibody. This was used to study the structure of antibodies, but it was not possible to produce identical antibodies specific to a given antigen. Dr.T.V.Rao MD

8. Fusion of Mice spleen cells with Myeloma cells produced Monoclonal antibodies Dr.T.V.Rao MD

9. Characters of Monoclonal Antibodies • Monoclonal antibodies (mAb) are a single type of antibody that are identical and are directed against a specific epitope (antigen, antigenic determinant) and are produced by B-cell clones of a single parent or a single hybridoma cell line. A hybridoma cell line is formed by the fusion of a one B-cell lymphocyte with a myeloma cell. Some myeloma cells synthesize single mAb antibodies naturally Dr.T.V.Rao MD

10. Hybridoma creates Monoclonal antibodies • Monoclonal antibodies are typically made by fusing myeloma cells with the spleen cells from a mouse that has been immunized with the desired antigen. However, recent advances have allowed the use of rabbit B-cells. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

11. Producing Monoclonal antibodies • First, a mouse is inoculated with the antigen to which the MA are to be produced. After this, the spleen is removed and fused with myeloma cells in order to produce the hybridomas that will be selected according to the antibody produced. Dr.T.V.Rao MD

12. Hybridoma leads to Proliferation Dr.T.V.Rao MD

13. Dr.T.V.Rao MD

14. Principles in Hybridoma technology • Inject the protein into amouse. • - remove the spleen. • - identify which spleen cells are producing antibodies. • - separate these cells and grow in tissue culture tubes. • - screen each Ab for cross reactivity. • - select the Ab which doesn't cross react with any other protein. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

15. Monoclonal antibodies are produced by Hybridoma technique Dr.T.V.Rao MD

16. Monoclonal – Diagnostic use • Although monoclonal antibodies were first produced in 1975 as research tools, scientists quickly recognized their practical uses, especially in diagnostic tests and in therapy. Several diagnostic procedures that use monoclonal antibodies are now available Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

17. A breakthrough in Diagnostics • A monoclonal antibody can be used to detect pregnancy only 14 days after conception. Other monoclonal antibodies allow rapid diagnosis of hepatitis, influenza, herpes, streptococcal, and Chlamydia infections. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

18. Helps in Critical Diagnostic decisions • They can be used to detect for the presence and quantity of this substance, for instance in a Western blot test (to detect a substance in a solution) or an immunofluorescence test. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

19. Monoclonal helps In Immunodiagnostic tests • Monoclonal antibodies can also be used to purify a substance with techniques called immunoprecipitation and affinity chromatography. Dr.T.V.Rao MD

20. Limitations with Mouse Monoclonals • Problem in medical applications is that the standard procedure of producing monoclonal antibodies yields mouse antibodies, and these are rejected by the human immune system Dr.T.V.Rao MD

21. Finding solutions for Human use • In one approach, one takes the DNA that encodes the binding portion of monoclonal mouse antibodies and merges it with human antibody producing DNA, in order to make bacteria produce antibodies that are half mouse and half human. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

22. Conjugated monoclonal antibody therapy: • Toxins or radioactive isotopes are bound to the constant region of the MAbs. When the MAb binds to the surface cells of a tumor the toxin or radioactivity will kill the cancer cells and all cells within a certain radius (a killing zone). In this way cancer cells within the tumour will be killed Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

23. Knowledge on Monoclonal advances • Mice have been genetically engineered to produce antibodies that have human constant regions (this is the part of the antibody that the human immune system recognizes as being foreign (mouse)). By using these hybrid (or chimeric monoclonal antibodies with human constant regions, the immune system only "sees" a human protein and does not react against them. So, they can be injected many times to kill all of the cells in a tumour. Dr.T.V.Rao MD

24. Monoclonal antibodies for cancer treatment • Possible treatment for cancer involves monoclonal antibodies that bind only to cancer cells specific antigen and induce immunological response on the target cancer cell (naked antibodies). mAb can be modificated for delivery of [toxin], radioisotope, cytokine. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

25. FDA approves • The example described in class is Herceptin. These monoclonal antibodies can be used against certain forms of breast cancer and have passed clinical trials and been approved for use by the FDA. Doctorrao’s ‘e’ learning series Dr.T.V.Rao MD

26. FDA approves and Trails on • The first FDA-approved therapeutic monoclonal antibody was a murine IgG2a CD3 specific transplant rejection drug, OKT3 (also called muromonab), in 1986. This drug found use in solid organ transplant recipients who became steroid resistant. Hundreds of therapies are undergoing clinical trials. Most are concerned with immunological and oncological targets. Dr.T.V.Rao MD

27. Created for Medical and Paramedical Students in the Developing world Dr.T.V.Rao MD Email doctortvrao@gmail.com Dr.T.V.Rao MD