1) Blood-derived Proteins and Vaccines:
Blood is the fluid connective tissue of humans. It is the most important medium for the transportation of gas and nutrients between tissues and sources. The blood forms the source for a number of therapeutically important proteins. A detailed understanding of the formation of blood cells (hematopoiesis) and detailed studies regarding the coagulation of blood have shown the presence of several useful proteins. In addition to blood-coagulating factors, whole blood and blood plasma have been used traditionally as blood products. These products are obtained from human volunteers who donate blood. But today some of the proteins of blood are produced by a recombinant technique. The blood coagulating factor known as factor VIII used in the treatment of hemophilia A and another factor, the factor IX for treating hemophilia B, etc., and the vaccine for hepatitis B are now synthesized by transgenic bacteria in fermentors.
2) Therapeutic Antibodies and Enzymes :
Antibodies and enzymes that are used for clinical applications are known as therapeutic antibodies. Polyclonal antibodies and monoclonal antibodies are examples. In tissue and organ transplantation, the body will recognize these as foreign objects and will produce antibodies against these tissues and organs leading to the failure of organ transplantation. Certain specific antibodies can be used against these natural antibodies and can revert the rejection process. For example, OKT-3 is used during kidney transplantation to revert the acute organ rejection in patients. Similarly, ReoPro is used to prevent blood clots. A large number of therapeutic antibodies are now produced by recombinant DNA techniques. Tissue plasminogen activator (t-PA) is an example of therapeutic enzyme used for acute myocardial infarction. There are a number of enzymes that are used as drugs. Asparaginase is used against some types of cancers and DNase is used for the treatment of cystic fibrosis.
3) Hormones and Growth Factors as Therapeutic Agents:
There are a number of proteins and peptides that act as hormones and growth factors. In the case of diseases due to metabolic errors such as diabeties, caused by the absence of these peptides, the concerned molecules can be administered to correct the metabolic errors. Insulin is the best example. In earlier times, insulin was prepared from the pancreas of cows and pigs. But now, human insulin is prepared through genetic engineering, by transferring the gene of insulin into bacteria; the transgenic bacteria will produce the active human protein. This insulin is called humulin. The methods of protein engineering have helped to develop altered forms of insulin, which are more active than the normal ones. There are a number of growth factors such as EGF (Epithelial Growth Factor) and plateletderived growth factors that are used for therapeutic purposes. EGF is used for the treatment of burns and injuries, during skin transplantation, for its growth. The platelet-derived growth factors are used for the treatment of diabetic and skin ulcers. A large number of growth factors and hormones are under clinical trials.
Tags: Bio Technology, Bio Genetics , Protein Products
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