Introduction Medical biotechnology is the fusion of genetics, cell

biology and many other sciences in order to further advances in medicine.

Why is medical biotechnology important?

The main reason for medical biotechnology is to prolong life.

Other reasons are to ease suffering of patients

1) Monoclonal Antibodies (mAb)

antibodies are specific proteins that target pathogens invading our body.

Steps in making them:

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.

This technology is used primarily to fight off cancer cells as these monoclonal antibodies can be “trained” to target markers that show up on cancer cells.

The mAbs will then destroy the cancer cell and go looking for more.

Monoclonal antibodies

2) Bioprocessing Bioprocessing is the mass production of human

proteins, vaccines, etc… by genetically modifying bacteria or viruses.

This allows for a large quantity of the desired product to be created in a short amount of time and for a relatively low cost.

The main product currently bioprocessed is insulin, the human protein responsible for lowering blood sugar after eating.

The human gene for insulin is placed into bacteria, these are cultured and allowed to produce insulin which is collected, purified and sold to the millions of diabetics worldwide.

What is insulin? Insulin is a hormone central regulating carbohydrate

and fat metabolism in the body.

Insulin causes liver cells, muscle cells and fat tissue to take up glucose from the blood and store it as glycogen in the liver and muscle.

Production of insulin Insulin is producted by the pancreas, which has two

important functions : 1. Producing hormones – insulin and glucagon which regulate blood sugar levels. 2. Producing pancreatic digestive enzymes.

Insulin is released when any of the several stimuli are detected– stimuli include ingested protein and glucose in the blood from digested food.

Insulin mutations Mutations in the insulin gene can cause type I or type

II diabetes. Reserchears have found at least 10 mutations - they suspect that the mutations alter the way insulin folds during its synthesis.

Reserchears suggest that these improperly folded proteins interfere with other cellular processes in ways that eventually kill the cells that produce insulin.

Insulin for medical purposes Insulin is being produced biosynthetically using

recombinant DNA technology.

Recently, reserchers have succeded in introducing the human insulin gene into plants and in producing insulin in them. This technique is set to reduce production costs.

Before it was possible to produce insulin biosynthetically it was aquired from animals and purified so it could be used as injections.

Why would we choose bacteria to make human insulin?

They reproduce quickly and are easy to grow.

Bacteria also have small circles of DNA called plasmids.

E. Coli

Route to the

Production by

Bacteria of Human

Insulin

Overview of gene

cloning.

Route to the Production by Bacteria of Human Insulin

A fermentor used to grow

recombinant bacteria. This is the step when gene cloning takes place.

The single recombinant plasmid replicates within a cell.

Then the single cell with many recombinant plasmids produces trillions of like

cells with recombinant plasmid – and the human insulin gene.

One cell with the

recombinant plasmid

The final steps are to collect the bacteria, break open the cells, and purify the

insulin protein expressed from the recombinant human insulin gene.

3) Stem Cells A stem cell is a cell that

has the potential to become any cell type in the human body.

Everyone has stem cells, but they are very hard to access.

The easiest place to get stem cells is from an embryo.

Stem cells are introduced into a damaged area of the body where, under the right conditions, will replace the damaged area.

Often times stem cells are grown in a lab first to ensure the right conditions and then placed into a sick person.

The main areas where stem cells have proven their worth is in bone marrow transplants, replacing damaged heart tissue after a heart attack and replacing damaged nerve tissue which gives hope to anyone who has had a spinal cord injury.

Embryonic Stem Cells

Subject stem

cells to specific

conditions to

encourage

differentiation

into one of

many cell types

4) Tissue Engineering A form of regenerative

medicine, tissue engineering is the creation of human tissue outside the body for later replacement.

Usually occurs on a tissue scaffold, but can be grown on/in other organisms as shown on the right.

Tissue engineers have created artificial skin, cartilage and bone marrow.

Current projects being undertaken include creating an artificial liver, pancreas and bladder.

Again, we are far from replacing a whole organ, but just looking for “refurbishing” our slightly used ones at the moment.

Gene therapy Delivery of therapeutic genes into the body to

correct disease conditions created by faulty gene

How is it done?

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