The term biotechnology encompasses any technique that uses living organisms (e.g., microorganisms) in the production (or) modification of products. Historically the classic definition of biotechnological drugs was that of proteins obtained from recombinant DNA technology. Foremost, recombinant DNA and monoclonal antibody (MAb) technologies are providing exciting opportunities for new pharmaceuticals development and new approaches to the diagnosis, treatment and prevention of diseases. The revolution in biotechnology is a result of recent research advancement in intracellular chemistry, molecular biology, recombinant DNA technology, genetics and immunopharmacology. Clearly biotechnology has established itself as a main stay in pharmaceuticals research and development.
The transition towards molecular medicine has already begun. As biotechnology advances, and growing numbers of cancer related genes are identified and cloned, -the therapy with biotechnological products will eventually supplement chemotherapy for many malignancies. More than 100 gene-therapy trails are in progress, genetically engineered for specific toxicity to cancer cells and are under clinical trials. A total of 54 biotechnological derived medications have been approved since human insulin in 1982. The commercial success of biotechnology has spurred the entry of many additional products into development pipelines.
Biotechnology allows for the development and production of new substances that were previously beyond the capacity of traditional technologies. This includes the design and production of new drugs with greater potency and specificity andconsequently, fewer side effects. One example of this is the treatment for multiple sclerosis.
Biotechnology offers a greater control over the manufacturingprocess, allowing significant reduction of risks of contaminationthrough infectious pathogens. An example is blood products used to treat Hemophilia. Biotechnology offers better product targeting for specificdiseases and patient groups, through the use of innovative technologies, in particular, genetics. Examples includE treatments for:Rare diseases, Lysosomal storage disorders & Cancer. Some products are not naturally created in sufficient quantities for therapeutic purposes. Biotechnology makes large-scale production of existing substance possible. One example of this is in the field of diabetes treatment. There are numerous techniques that are utilized to createbiotechnological products. These include
Recombinant DNA technology
Monoclonal antibody technology
Polymerase chain reaction
Nucleotide blockade (or) antigenic nucleic acids
Recombinant DNA ( r DNA )
DNA, deoxyribonucleic acid, has been called "the substance of life". It is the DNA that constitutes genes allowing cells to reproduce and maintain life. In 1950s, James D. Watson and Francis H.C. Crick postulated the structure of DNA. Watson and Crick described their model of DNA as a double helix, two strands of DNA coiled about itself like a spiral staircase. It is now known that the two strands of DNA are connected by the bases adenine, guanine, cytosine and thymine(A,G,CandT). The ability to selectively hydrolyze a population of DNA molecules with a number of endonucleases promoted a technique for joining two different DNA molecules termed
recombinant DNA. Recombinant DNA technology allows the removal of a specific piece of DNA out of larger, more complex molecule. Consequently, recombinant DNAs have been prepared with DNA fragments from bacteria combined with fragments from humans, viruses with viruses and so forth. The ability to join two different pieces of DNA together at specific sites within the molecules is achieved with two enzymes, a restriction endonuclease and a DNA ligase.
When a foreign body or antigen molecule enters the body an immune response is initiated. This molecule may contain several different antigenic determinants and lines of B-lymphocytes will proliferate, each secreting an immunoglobulin (i.e., an antibody) molecule that fits a single antigenic determinant or part of it. Monoclonal antibodies are produced as a result of perpetuating the expression of a single B-lymphocyte. Through the development of hybridoma technology developed from the Kohler and Milsteins research it has been possible to produce identical, monospecific antibodies in almost unlimited quantities.These are constructed by the fusion of B-lymphocytes, Monoctonal antibodies icniato~ fnr ri iltiwatin stimulated with a specific, antigen, with immortal myeloma cells.The resultant hybridomas can then be maintained in cultures and are capable of producing large amounts of antibodies.
Polymerase chain reaction
Polymerase chain reaction is a biotechnological process whereby there is substantial amplification (i.e., over 100,000 fold) of a target nucleic acid sequence (gene). This enzymatic reaction occurs in repeated cycles of a three step process. First, DNA is denatured to separate the two strands. Then a nucleic acid primer is hybridized to each DNA strand at a specific location within the nucleic acid sequence. Then a DNA polymerase enzyme is added for extension of the primer along the DNA strand to copy the target nucleic acid sequence. Each cycle duplicates the DNA molecules copied. This cycle is repeated until sufficient DNA sequence material is copied. For example, 20 cycles with a 90% success rate will yield a 375,000 amplification of a DNA sequence.
The simplest representation of this polymerase chain reaction is represented as below.
Example of the technique of DNA cloning into a plasmid.:Insertion of the gene coding for insulin into a bacterial plasmid, which in turn carries the gene into a replicating bacterial cell that produces human insulin.
Plasmid: Plasmids are small circles of DNA found in bacteria cells, separate from the bacterial chromosome and smaller than it. They are able to pass readily from one cell to another, even when the cells are dearly from different species, far apart on the evolutionary scale. Consequently, plasmids can be used as vectors, permitting the reproduction of a foreign DNA by using the bacterial replicating system.
cDNA: Human genes composed of coding and non-coding sequences. The copy of the coding sequences is called cDNA. It can be obtained from the reverse transcription of messenger RNA. The transcription and translation of the insulin cDNAwill allowthe production of a functional insulin molecule.
Transfer of the Insulin gene into a plasmid vector
- The plasmid is cut across both strands by a restriction enzyme, leaving loose, sticky ends to which DNA can be attached.
· Special linking sequences are added to the human cDNA so that it will fit precisely into the loose ends of the opened plasmid DNA ring.
· The plasmid containing the human gene, also called a recombinant plasmid, is now ready to be inserted into another organism, such as a bacterial cell.
Cloning the Insulin gene
The recombinant plasmids and the bacterial cells are mixed up. Plasmids enters the bacteria in a process called transfection. With the recombinant DNA molecule successfully inserted into the bacterial host, another property of plasmids can be exploited - their capacity to replicate. Once inside a bacterium, the plasmid containing the human cDNA can multiply to yield several dozen copies.When the bacteria divide, the plasmids are divided between the two daughter cells and the plasmids continue to reproduce. With cells dividing rapidly (every 20 minutes), a bacterium containing human cDNA (encoding for insulin, for example) will shortly produce many millions of similar cells (clones) containing the same human gene.
Gene therapy is a process in which exogenous genetic material is transferred into somatic cells to correct an inherited or acquired gene defect. Also it is intended to introduce a new function or property into cells. These include common and life threatening diseases like cystic fibrosis, hemophilia, sickle cell anemia and diabetes. Research has examined the use of a "self renewing" stem cell population for the therapeutic transfer of genetic material. Stem cells can self renew themselves. As an example, a patient cells (e.g., T-lymphocytes) are harvested and grown within the laboratory. The cells receive the gene from a viral carrier and start to produce the missing protein necessary to correct the deficiency. The genetic cause of numerous primary immune deficiency disorders has been discovered and described. As a result, gene therapy can now be
used as an alternative therapy.