MONOCLONAL antibodies : MONOCLONAL antibodies Dr.T.V.Rao MD Beginning of Monoclonal Era : Beginning of Monoclonal Era Georg Kohler and Cesar Milstein fuse 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. Discovery of Monoclonal Antibodies : 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. Nobel prize in Medicine and Physiology was awarded to Köhler, Milstein and Jerne in 1984 : Nobel prize in Medicine and Physiology was awarded to Köhler, Milstein and Jerne in 1984 Monoclonal Antibodies : 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 Nomenclature : 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 Study of Myeloma leads to Discovery of Monoclonal antibodies : 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. Fusion of Mice spleen cells with Myeloma cells produced Monoclonal antibodies : Fusion of Mice spleen cells with Myeloma cells produced Monoclonal antibodies Characters of Monoclonal Antibodies : 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 Hybridoma creates Monoclonal antibodies : 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 Producing Monoclonal antibodies : 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. Hybridoma leads to Proliferation : Hybridoma leads to Proliferation Principles in Hybridoma technology : Principles in Hybridoma technology inject the protein into a mouse.
- 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 Monoclonal antibodies are produced by Hybridoma technique : Monoclonal antibodies are produced by Hybridoma technique Monoclonal – Diagnostic use : 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 A breakthrough in Diagnostics : 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 Helps in Critical Diagnostic decisions : 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 Monoclonal's helps In Immunodiagnostic tests : Monoclonal's helps In Immunodiagnostic tests Monoclonal antibodies can also be used to purify a substance with techniques called immunoprecipitation and affinity chromatography. Limitations with Mouse Monoclonals : 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 Finding solutions for Human use : 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 Conjugated monoclonal antibody therapy: : 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 tumor will be killed
Doctorrao’s ‘e’ learning series Knowledge on Monoclonal’s advances : Knowledge on Monoclonal’s 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 tumor. Monoclonal antibodies for cancer treatment : 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 FDA approves : 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 FDA approves and Trails on : 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. Created for Medical and Paramedical Students in the Developing world : Dr.T.V.Rao MD
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