Applications of Biotechnology in Health

Lecture # 2

Dr. Abdul Jabbar Assistant Professor MUST, Mirpur

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Practical Applications of Biotechnology

1. Medical applications — diagnostics, vaccines, medicines, Gene therapy, monoclonal antibodies etc.

2. Agricultural applications — better crops, High yield,

Insect/pest resistant crops, improved pharming etc. 3. Industrial and environmental applications — better

manufacturing processes and consumer products, eliminating the toxic substances etc.

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To identify and manage the root cause of diseases

To fight and cure diseases

To find ways for better health

Goals of Biotechnology in Medicine

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Medical biotechnology corresponds to

Production of Drugs and Therapeutics Analysis of the Genes in genetic disease Correction of genetic defects

Development of Genetically modified organisms

(GMO’s)

Applications of biotechnology in medicine

• Production of new and improved crops/foods, industrial chemicals, pharmaceuticals and livestock

• Stem cells • Diagnostics for detecting genetic diseases/disorders • Gene therapy • Anti-cancer drugs • Vaccine development (recombinant vaccines) • Antibiotics • Human growth hormones • Monoclonal antibodies • Human Genome Project etc.

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Monoclonal Antibodies

Molecular Biology

Cell Culture

Genetic Engineering

Anti-cancer drugs

Diagnostics Culture of plants from single cells

Transfer of new genes into animal

organisms

Synthesis of specific DNA

probes

Localisation of genetic disorders

Tracers

Cloning

Gene therapy

Mass prodn. of human proteins

Resource bank for rare human chemicals

Synthesis of new proteins

New antibiotics

New types of plants and animals

New types of food

DNA technology

Crime solving

Banks of DNA, RNA and proteins

Complete map of the human genome

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The history of biotechnology begins when primitive people became domesticated enough to breed plants and animals; gather and process herbs for medicine; make bread and wine; create many fermented food products including yogurt, cheese and various soy products; create septic systems to deal with their digestive and excretory waste products, and to create vaccines to immunize themselves against diseases. It is evident that biotechnology in the past has concentrated on the production of food and medicine and the use of biotechnology to solve environmental problems

Historical background

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Gene cloning in Medicine

Gene cloning/Genetic engineering gives scientists the ability to improve and alter the basic composition of a living cell.

In this process, gene of interest is inserted into a cell’s DNA to make a specific protein.

The cell will manufacture the protein which affects a particular characteristic and the cell will also pass the new instructions on to its offspring.

This is useful for the production of insulin, human growth hormones etc.

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Bacterium

Bacterial chromosome

Plasmid

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1 Gene inserted into plasmid Cell containing

gene of interest

Recombinant DNA (plasmid)

Gene of interest

Plasmid put into bacterial cell

DNA of chromosome (“foreign” DNA)

Recombinant bacterium

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Gene Cloning

Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest

Gene of interest

Protein expressed from gene of interest

Protein harvested Copies of gene

Basic research and various applications

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4 Basic research on protein

Basic research on gene

Gene for pest resistance inserted into plants

Gene used to alter bacteria for cleaning up toxic waste

Protein dissolves blood clots in heart attack therapy

Human growth hormone treats stunted growth

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Stem Cells A stem cell is a unspecialized cell that can reproduce

itself indefinitely and differentiate into specialized cells of one or more types

Stem cells are of two types: Embryonic stem cells Non-embryonic stem cells "somatic" or "adult" stem

cells. Stem cells isolated from early embryos at the blastocyst

stage are called embryonic stem (ES) cells; these are able to differentiate into all cell types

The adult body also has stem cells, which replace non-reproducing specialized cells called Non-embryonic stem cells. Also called "somatic" or "adult" stem cells.

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Cultured stem cells

Different culture conditions

Different types of differentiated cells

Embryonic stem cells

Adult stem cells

Cells generating all embryonic cell types

Cells generating some cell types

Liver cells

Nerve cells

Blood cells

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Remove skin cells from patient. 2

1

3

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Reprogram skin cells so the cells become induced pluripotent stem (iPS) cells.

Patient with damaged heart tissue or other disease

Return cells to patient, where they can repair damaged tissue.

Treat iPS cells so that they differentiainto a specific cell type.

• Researchers can transform skin cells into ES cells by using viruses to introduce stem cell master regulatory genes

• These transformed cells are called iPS cells (induced pluripotent cells)

• These cells can be used to treat some diseases and to replace nonfunctional tissues

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Diagnosis and Treatment of Diseases

• One benefit of DNA technology is identification of human genes in which mutation plays a role in genetic diseases

• Scientists can diagnose many human genetic disorders using PCR and sequence-specific primers.

• Then identify the disease-causing mutations.

• Genetic diseases can be treated by gene therapy.

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Gene Therapy

Gene therapy is the alteration of an affected individual’s genes

Gene therapy holds great potential for treating disorders traceable to a single defective gene

Vectors are used for delivery of genes into specific types of cells, for example bone marrow

Very expensive and new technology

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Cloned gene

2

1

3

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Retrovirus capsid

Bone marrow cell from patient

Viral RNA

Bone marrow

Insert RNA version of normal allele into retrovirus.

Let retrovirus infect bone marrow cells that have been removed from the patient and cultured.

Viral DNA carrying the normal allele inserts into chromosome.

Inject engineered cells into patient.

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• SNPs (single nucleotide polymorphisms) is a genetic marker and occurs on average every 100–300 base pairs.

• SNPs can be detected by PCR. • Any SNP shared by people affected with a disorder but not

among unaffected people may pinpoint the location of the disease-causing gene.

• SNPs may be associated with a disease-causing mutation. • SNPs may also be correlated with increased risks for

conditions such as heart disease or certain types of cancer

Single Nucleotide Polymorphisms (SNPs)

SNP Normal allele

Disease-causing allele

T

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• Pharmaceutical products (proteins) can be synthesized on a large scale

• Host cells in culture can be engineered to secrete a protein, simplifying the task of purifying it

• This is useful for the production of insulin, human growth hormones and vaccines

• Before 1982, the main sources of this hormone were pig and cattle tissues obtained from slaughter houses.

• Insulin extracted from these animals is chemically similar, but not identical to human insulin, and it causes harmful side effects in some people.

• The drug imatinib is a small molecule that inhibits over-expression of a specific leukemia-causing receptor

Synthesis of therapeutic proteins and Drugs

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Human insulin produced by bacteria – In 1982, Humulin became the first recombinant

drug approved by the Food and Drug Administration (FDA).

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Vaccines • DNA technology is also helping medical researchers to

develop vaccines. • A vaccine is a harmless variant or derivative of a pathogen

(usually a bacterium or virus) that is used to prevent an infectious disease.

• When a person is inoculated by vaccine, the vaccine stimulates the immune system against the pathogen.

• For the many viral diseases for which there is no effective drug treatment, prevention by vaccination is the only medical way to prevent illness.

• Smallpox was once a dreaded human disease, but it was eradicated worldwide in the 1970s by widespread vaccination with a harmless variant of the smallpox virus.

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Edible Vaccines

Bananas have potential to become the

world's first edible vaccine. An edible

vaccine doesn't need sterile syringes,

costly refrigeration, or multiple

injections. Thus, researchers are

looking into making the food

vaccines. Carrots and other

vegetables have also potential for

edible vaccines.

Genetically Modified Organisms (GMO’s) A genetically modified organisms (GMO) is one that is produced by incorporating one or more genes by artificial means (gene cloning). The new gene may be or may not be from another species. To make genetically modified plants, researchers manipulate the DNA of a single somatic cell and then grow a plant with a new trait. A number of crop plants carrying new genes for desirable traits, such as delayed ripening and resistance to spoilage and disease are already in commercial use. e.g. flavorsavr tomatoes. The majority of the soybean and cotton crops are genetically modified like Bt cotton which received genes that make them resistant to insects.

Health benefits include “Golden rice” which produces grains containing beta-carotene, which our body used to make vitamin A. Similarly genetically modified animals can also be produced with desired traits like more meat, milk and may be used as pharmaceutical “factories” to produce biological substances for medical use.

• Transgenic animals are made by introducing genes from one species into the genome of another animal

• Transgenic animals are called pharmaceutical “factories,” • They are producers of large amounts of rare substances for

medical use. Recently, researchers have engineered transgenic chickens that express large amounts of the foreign product in their eggs.

• Gene pharming is the use of transgenic farm animals to produce therapeutic drugs in the animal’s milk.

• An anti-clotting medicine is currently being produced by a herd of goats.

• Animals have also been genetically altered to serve as organ donors. 24

Biotechnology Products from animals for health purposes

Transgenic mice

• Two baby mice - same age • Human Growth hormone

inserted into the embryo of the mouse on the left. Causes rapid growth in the newborn

• The mouse on the right is a normal sized mouse

Xenotransplantation • Fifty thousand Americans need transplants a year,

but only 20,000 patients get them. • Unfortunately, however, there are not enough

human donors to go around. • As many as 4,000 die a year while waiting for an

organ.

• Scientists have begun the process of genetically engineering animals to serve as organ donors for humans who need a transplant.

• We now have the ability to transplant kidneys, heart, liver, pancreas, lung and other organs.

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Xenotransplantation • We might think that apes, such as the chimpanzee or the

baboon might be a scientifically suitable species for this purpose but apes are slow breeders and many people object to use apes for this purpose.

• In contrast, pigs have been an acceptable meat source, and a female pig can become pregnant at six months and can have two babies a year, each averaging about ten offspring.

• However, the human body rejects transplanted pig organs.

• Genetic engineering, however, can make pig organs good for transplantation at less of a rejection risk.

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Pig Cloning

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Human Ear on Mouse

Human ears are sometime lost through accidents. Mouse cells can be “tricked” into growing the outer portion of the human ear, which is then surgically transferred to the human patient.

Biotechnology Products From Plants for health purposes

Plants are also being engineered to produce human hormones, clotting factors, and antibodies in their seeds.

One type of antibody made by corn can deliver a substance that kills tumor cells and another made by soybeans can be used as treatment for genital herpes.

There are plans to produce drugs for the treatment of cystic fibrosis, cancer, blood diseases and other disorders from plants. 30

Golden Rice

Golden rice is the result of an effort to develop rice varieties that produce pro-vitamin-A (beta-carotene). It is used to fulfill the vitamin A deficiencies in the diets. Because traditional rice varieties do not produce pro-vitamin-A, so transgenic technologies were required.

Antibody An antibody is a protein (immunoglobulin) used by the

immune system to identify and neutralize foreign objects like bacteria and viruses etc. Each antibody recognizes a specific antigen unique to its target.

According to differences in their heavy chain constant domains, antibodies are grouped into five classes, or isotypes: IgG, IgA, IgM, IgD, and IgE.

Polyclonal antibodies are mixture of different types of antibodies.

Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell.

Making Monoclonal Antibodies

Now Immortal!

Principle use is in diagnostics.

Prevention of allogeneic immune response to mixed sequences in non-antigen binding regions.

Clone producing the antibody can be amplified to produce unlimited quantities of monoclonal antibodies as a pharmaceutical source.

Clone cell lines can be preserved indefinitely in an ultra-freezer and revived when needed.

Antibody coding information can be engineered to precise sequential specifications to produce desired target binding and to avoid adverse immunological reactions.

Monoclonal antibodies (mAb) act directly when binding to a cancer specific antigens and induce immunological response to cancer cells, such as inducing cancer cell apoptosis, inhibiting growth, or interfering with a key function.

Potential Advantages of Monoclonal Antibodies

DNA Fingerprinting • DNA fingerprinting is identifying the pattern of certain

sequences in parts of DNA • DNA is isolated, copied, cut into pieces, and separated

based on size using gel electrophoresis. • Probes are then used to find specific DNA sequences. • Can be used for maternity or paternity tests and in

forensics to determine identity and compare unknown DNA samples to find out if a suspect is guilty or not.