Biopharmaceutical products and vaccines Flashcards
Biotechnology uses _________ to create products or processes that ____________________
living organisms
help improve the quality of life for humans or other organisms.
Is a science dating back to ancient civilizations when microbes were used to make products like wine and beer, vinegar, breads, and cheeses.
Biotechnology
Modern Biotech began shortly after
recombinant DNA technology was developed.
Genetic engineering, Genetic modification is the ability to
manipulate DNA in vitro and to introduce genes into living cells has allowed scientists to generate new varieties of plants, animals, and other organisms with specific traits.
Genetic engineering typically involves the use of
recombinant DNA technologies
Genetic engineering typically involves the use of recombinant DNA technologies to
add a gene or genes to a genome, but it can also involve gene removal.
(GMOs).
genetically modified organisms
Genome editing
can potentially edit DNA in vivo to introduce specific mutations in a very precise manner, without introducing additional DNA into the recipient organism.
An example of a GMO
E. coli in colonies, have been genetically engineered to produce lycopene – an antioxidant found in abundance in tomatoe, giving them their characteristic red-color
Biopharming produces valuable proteins in genetically modified (GM) animals and plants. GMOs are used extensively in the pharmaceutical industry for the production of a variety of products, especially
therapeutic proteins to treat diseases.
Prior to recombinant DNA, biopharmaceuticals such as insulin, were purified from
the pancreas.
The first commercial biotech product, manufactured by recombinant DNA technology, was human insulin, called
Humulin®, was licensed for therapeutic use in 1982.
Previously, insulin was chemically extracted from the pancreas of
cows and pigs at abattoirs.
Shortly after insulin, the __________________ was cloned, and turned into a commercial product to treat children who suffer from a form of dwarfism.
human growth hormone gene
Many therapeutic proteins have since been produced by expressing human genes in bacteria.
In most cases, the human gene is cloned into a ______, and the _________ is introduced into the bacterial host, which are grown in large industrial fermenters, and the recombinant human proteins are _________ from these bacterial cultures.
plasmid
recombinant vector
recovered and purified
Bacterial expression systems often fail to properly process the ___________________ required for eukaryotic proteins to be fully functional.
post-translational modifications (like glycosylation or phosphorylation)
In addition, eukaryotic proteins produced in bacterial cells often do not ______________________ required for functionality.
fold into the proper three-dimensional conformation
Other expression hosts include yeast and even insect cell lines.
They are able to overcome differences observed between expressing human proteins in pro- vs. eukaryotic systems.
Transgenic animal systems can solve these problems
– examples are yeast cells, insect cell lines, or transgenic animals, which can act as living ‘bioreactors’ or ‘biofactories’.
In 2006, antithrombin (anticlotting protein in blood)
became the first drug to be produced in the milk of farm animals, after the human antithrombin gene was expressed in the mammary glands of goats.
In one year, a single goat will produce the equivalent amount of antithrombin that would require
∼90,000 human blood collections.
Chickens are easier to rear and more efficient as biofactories
– very efficient in glycosylating recombinant proteins.
Kanuma is made from _____________ expressing a recombinant form of the enzyme ______________________, that is used as a medication for the treatment of __________________.
the eggs of GM chickens
lysosomal acid lipase (LAL), or sebelipase alfa
lysosomal acid lipase deficiency
2 types of vaccines:
Inactivated vaccines and attenuated vaccines
Inactivated vaccines
are prepared from ‘killed’ versions of the infectious virus or bacteria,
e.g. Rabies and Influenza
Attenuated vaccines
are ‘live’ viruses or bacteria that can no longer reproduce but can cause a mild form of the disease,
e.g. Tuberculosis, cholera, and chickenpox.
Genetic engineering is being used to produce subunit vaccines, which consist of
one or more antigenic surface proteins from the virus or bacterium rather than the entire virus or bacterium, e.g. Johnson&Johnson SARS-Cov-2 vaccine.
In subunit vaccines the surface protein acts as
an antigen that stimulates the immune system to make antibodies that act against the organism from which it was derived.
In 2005,
the FDA approved Gardasil®, a subunit vaccine that targets four strains of human papillomavirus (HPV) that cause cervical cancers.
In 2014,
the National Department of Health introduced HPV vaccination as a central strategy for cervical cancer prevention in South Africa. Cervical cancer is the 2nd most common cancer among South African women.
Plants offer several advantages for
expressing recombinant proteins.
Advantages of vaccine production in plants
- Once a transgenic plant is created, it can easily be grown and vegetatively propagated in a greenhouse or field to provide a constant source of recombinant protein.
- The cost of expressing a recombinant protein in a transgenic plant is much lower than making the same protein in bacteria, yeast, or mammalian cells.
disadvantages of vaccine production in plants
temperature sensitivity and sterile conditions for administering.
Antibodies against Ebolavirus were expressed in tobacco leaves.
Ebola monoclonal antibody genes from transgenic mice were introduced into tobacco plants, which expressed high quantities of the antibody proteins. These can be isolated and purified for use in humans.
A vaccine against a bacterium that causes cholera has been produced
in genetically engineered potatoes and used to successfully vaccinate human volunteers.
DNA-based vaccines relies on the fact that
inserted recombinant DNA would express pathogen-specific proteins, which would trigger an immune response.
How do DNA-based vaccines work?
DNA encoding proteins from a particular pathogen are inserted into plasmid vectors, which are then injected directly into an individual or delivered via a viral vector similar to the way certain viruses are used for gene therapy.
Example of DNA vaccine:
Trials with DNA expressing the pre-membrane and envelope proteins of Zikavirus (ZIKV – causes microcephaly) created high levels of antibodies in mice and Rhesus monkeys and was capable of neutralizing ZIKV and protecting against ZIKV infection – now in human clinical trials.
mRNA vaccines
an mRNA is stabilised and injected, will be translated into an antigenic protein that will stimulate the immune system to produce antibodies, e.g. the Pfizer SARS-Cov-2 vaccine.
