The recombinant DNA technological processes have made great impact in the area of healthcare by mass production of safe and more effective therapeutic drugs. A large number of human genes encoding pharmaceutically valuable proteins have been cloned and expressed in microorganisms largely employed by biotech pharmaceuticals. Initially, E. coli was used as the host for obvious reasons of ease in cloning. But yeast is fast becoming the host of choice for production of recombinant proteins in many of the Applications of Biotechnology in Medicine.
Several of the recombinant proteins, used for treatment of diabetes mellitus (insulin), dwarfism (human growth hormone),cancer (interferons, interleukins, granulocyte macrophage colony stimulating factor), thrombosis (streptokinase), and AIDS (interferons, granulocyte macrophage colony stimulating ; factor) has been produced .
Production of genetically modified insulin using Applications of Biotechnology
Human insulin is made up of 51 amino acids arranged in two polypeptide chains, A having 21 amino acids and B with 30 amino acids. The two polypeptide chains are interconnected by two disulphide bridges or S-S linkages. An S-S linkage also occurs in A chain.
In mammals, including humans, insulin is synthesized as a pro-hormone which contains an extra stretch called the C peptide (with 33 amino acids). This C peptide is not present in the mature insulin and is removed during maturation into insulin. The pro-hormone needs to be processed before it becomes a fully mature and functional hormone. Bacteria can not be made to synthesize insulin from its gene because of the presence of introns in eukaryotic genes. Bacteria do not possess enzymes for removing introns. It was challenging to produce insulin using rDNA technique and to assemble insulin into its mature form. In 1983, Eli Lilly, an American company, prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E.coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin (‘Humulin’) and it is found as one of the many uses of biotechnology in medicine.
Production of recombinant vaccines using Applications of Biotechnology
Conventional vaccines consist of attenuated or inactivated pathogens. In case of many pathogens, the gene encoding a critical antigen has been isolated and are expressed in bacteria/animals, and the recombinant protein so produced is used as a vaccine such vaccines are called recombinant vaccines and are helpful in biotech research.
Usually the entire protein molecule is not necessary for an effective immunization since the antigenic property is ordinarily localized in a small part of protein molecules. Therefore, either a constituent polypeptide (in case of heteromultimeric proteins) or a small part of a polypeptide may be used as a vaccine such vaccines are known as subunit vaccines and considered one of the several applications of biotechnology.
DNA vaccines in Applications of Biotechnology
DNA vaccines are composed of a small, circular piece of DNA- called a DNA plasmid – that contains genes which code for proteins of a pathogen. When the vaccine is injected into the host, the inner machinery of the host cells ‘reads’ the DNA, converts it into proteins from the pathogen. Recognizing that the protein is foreign, the cells display them on their surface to alert the body’s immune system- both helper T-cells, which spur the production of antibodies, and killer T-cells. This triggers a range of immune responses and therefore, DNA vaccines induce wider range of immune responses.
Production of monoclonal antibodies using Applications of Biotechnology
Monoclonal antibody is a specific antibody produced from a normally short lived antigen-activated B-cell that has been immortalized by hybridizing it with a myeloma cell by hybrid cell culture technique known as hybridoma technology which is one of the typical applications of biotechnology examples and mostly used by biotech pharma.
1) A mouse is injected with a specific antigen that will produce antibodies against that antigen.
2) The spleen of the mouse is removed and a suspension is made. The suspension includes B cells that produce antibodies against the injected antigen.
3) The spleen cells are then mixed with myeloma cells that are capable of continuous growth in culture but have lost the ability to produce antibodies. Some of the antibody-producing spleen cells and myeloma cells fuse to form hybrid cells. These hybrid cells are now capable of growing continuously in culture while producing antibodies.
4) The mixture of cells is placed in a selective medium that allows only hybrid cells to grow.
5) Hybrid cells proliferate into clones called hybridomas. The hybridomas are screened for production of the desired antibody.
6) The selected hybridomas are then cultured to produce large amounts of monoclonal antibodies.
While this article mainly focuses on the uses of biotechnology in medicine, you can read other applications of Biotechnology here: