Lec 16 Medical biotechnology Shah Rukh Abbas, PhD

Introduction Medical biotechnology is the fusion of genetics, cell biology and many other sciences in order to further advances in medicine. The main reason for medical biotechnology is to – Prolong life – Ease sufferings – Easy and early diagnostics – Minimize side effects – Point of care (increase accessibility for people with disabilities).

Molecular diagnostics – Protein based (Monoclonal Antibodies (mAb) – Gene based (DNA diagnostics ) 1. Sensitivity 2. Specificity 3. Simplicity Molecular Therapeutics – Stem cells – Nanotechnology (Molecular (Non-viral) theranostic potential) Current Areas of Research Commercially driven

Monoclonal Antibodies (mAbs) An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. Each antibody recognizes a specific antigen unique to its target. Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell, all clones of a single parent cell. Polyclonal antibodies are antibodies that are derived from different cell lines. They differ in amino acid sequence.

Structure of AB

Main characteristic of mAB 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

Production of mABs

1.Human antibody genes are put into a mouse. 2.Mouse is infected causing it to make human antibody producing cells (B-cells). 3.These cells are removed from the mouse and fused with a tumour cell. 4.Now we have a tumour cell that is constantly producing antibodies and more cells like itself. Steps

Hybridoma technology Hybridoma creates Monoclonal antibodies and therefore also called hybridoma technology – Monoclonal antibodies are typically made by fusing myeloma cells with the spleen cells from a mouse that has been immunized with the desired antigen. Application in 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. – 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.

Enzyme-linked immunosorbent assay (ELISA) Addition of a specific antibody (primary antibody) which will bind to the test molecule if it is present. Washing to remove unbound molecules. Addition of secondary antibody which will bind to the primary antibody. The secondary antibody usually has attached to it an enzyme e.g. alkaline phosphatase. Wash to remove unbound antibody. Addition of a colourless substrate which will react with the secondary antibody to give a colour reaction which indicates a positive result.