Animal Pharming Red Biotechnology

Learning Outcomes

1.  To define biologics and establish its importance in the pharmaceutical industry

2.  To trace the development of bioreactors up to the creation of animal pharming and explain the basis for these technologies

3.  To identify the advantages and disadvantages of animal pharming for pharmaceutical production

4.  To evaluate the ethical, safety and legal issues related to animal pharming

Learning Outcome #1

1.  To define biologics and establish its importance in the pharmaceutical industry

Pharmaceutical Drugs

Synthetic •  Small Molecules

Natural •  Conventional

•  Recombinant/Biologics

Small Molecules vs Biologics

BioMarket TrendsMore » May 15, 2012 (Vol. 32, No. 10)

The First Licensed Biologic

Learning Outcomes

2.  To trace the development of bioreactors up to the creation of animal pharming and explain the basis for these technologies

3.  To identify the advantages and disadvantages of animal pharming for pharmaceutical production

Bacterial Factories

What Bacteria Can’t Do

Mammalian Cell Factories

First Attempt at Animal Pharming

alpha1-antitrypsin

First Licensed Animal Pharm Biologic

Biologics Harvested From…

Bioreactors for Biologics

2 BioMed Research International

Table 1: Comparison of the different systems used to producerecombinant pharmaceutical proteins.

Bacteria Mammaliancells

Transgenicanimals

Production level ++ + ++++Investment cost +++++ + +++Production cost +++++ ++ ++++Scaling-up ability +++++ + ++++Collection +++++ +++++ ++++Purification +++ ++++ +++Posttranslationalmodifications + ++++ ++++

Glycosylation + ++++ ++++Stability of product +++++ +++ ++++Contaminant pathogens +++++ ++++ ++++Products on the market ++++ +++++ +++Table adapted from [1].

Table 2: Comparative estimated production cost between cellculture and transgenics.

Production scale(Kg/year) System Cost

(dollars/gram product)

50 Cell culture 147Transgenics 20

100 Cell culture 48Transgenics 6

Table adapted from [7].

cost of building a commercial cell-culture facility [10]. Asshown in Table 2, protein production costs are substantiallylower for transgenic animals than for cell culture. Therefore,transgenic animal bioreactors show a financial advantageover cell culture or other systems, even when all costs aretaken into account.

Recombinant proteins are produced from transgenicanimal body fluids. Milk, egg white, blood, urine, seminalplasma, and silkworm cocoon from transgenic animals arecandidate sources of recombinant proteins produced at anindustrial scale.

The technology for using the mammary glands of trans-genic animals as primary bioreactors has been developedfor large transgenic animals, such as cows, goats, sheep,and pigs. Instead, many laboratories and pharmaceuticalcompanies have made efforts to produce a variety of valuabletherapeutic proteins using transgenic rabbits. In this paper,we compared different systems and species of transgenicanimal bioreactors.

2. Protein Production Platforms UsingTransgenic Animals

In 1985, Hammer and colleagues established the first trans-genic livestock animals, including sheep, rabbits, and pigs, inan attempt to develop a way to produce recombinant proteins

from these animals [11]. Since then, production of a numberof recombinant proteins from transgenic animals has beenreported. Many laboratories and pharmaceutical companieshavemade efforts to produce a variety of valuable therapeuticproteins from transgenic animals, such as cows, pigs, sheep,goats, and rabbits [7, 8, 12, 13].

Selection of a suitable method for expressing a recombi-nant protein is dependent on the characteristics and intendedapplication of the recombinant protein [14]. Presently, milkis the most mature system for producing recombinant pro-teins from transgenic organisms. Blood, egg white, seminalplasma, silk gland, and urine are other theoretically possi-ble systems. The advantages and disadvantages of differentexpression systems are shown in Table 3.

2.1. Mammary Gland, the Best Bioreactor Available. Themammary gland has generally been considered the organ ofchoice to express valuable recombinant proteins in transgenicanimal bioreactors because milk is easily collected in largevolumes. Milk is currently the best available bioreactor.Foreign proteins are commonly reported to be produced intransgenicmilk at rates of several grams per liter. Based on theassumption of average expression levels, daily milk volumes,and purification efficiencies, 5.400 cows would be needed toproduce the 100.000 kg of human serum albumin that arerequired per year worldwide, 4.500 sheep would be requiredfor the production of 5000 kg !-antitrypsin (!-AT), 100 goatsfor 100 kg of monoclonal antibodies (mAbs), 75 goats for75 kg of antithrombin III, and two pigs to produce 2 kg ofhuman clotting factor IX [15]. As a result, a great deal of efforthas been made to produce transgenic bioreactors not onlywith the traditional “dairy” species, such as sheep, goats, andcows, but also with rabbits and pigs.

A number of examples leave no doubt about the capacityof the mammary gland to synthesize, mature, and secreteforeign proteins. Apart from these successes, a certain num-ber of failures in animal mammary gland systems haveoccurred for various reasons: (1) purely technical issues suchas problems in the generation of transgenic mammals, (2)the need for more fundamental knowledge in areas such asprotein maturation or secretion, and (3) the fact that certainbioactive proteins produced in milk can have adverse affectson an animal’s health; this is particularly true when theyare produced at high concentrations and the protein can bereabsorbed.

2.2. Blood and Egg: Alternative Recombinant Protein SecretionMedium. The mammary gland of a transgenic animal isthe most popular protein bioreactor. However, there arealternative systems based on production of useful pharma-ceutical proteins in blood and eggs [16]. Animal blood, whichcollects secretions from many tissues, may be used as asource of recombinant proteins. For example, human !-ATwas obtained at a high level from the serum of transgenicrabbits [17], and human hemoglobin has been produced in atransgenic swine circulatory system. This protein seemed tohave been matured appropriately for its functionality [18, 19].In principle, the human component of the pigs’ blood was

Wang et al. 2013. BioMed Research International, Article ID 580463. doi:10.1155/2013/580463

Unit Cost of Production

Animal Pharming

cow lactoferrin treatment of GI tract infection, treatment of infectious arthritis

cow human serum albumin maintains blood volume

chicken, cow, goat monoclonal antibodies other vaccine production

Table 2: AviGenics comparison of production inputs and costs for monoclonal antibodies* using traditional cell culture versus using transgenic poultry or goats

Traditional Cell Culture Poultry Eggs Goat Milk

Raw Material Volume (kg)170,000 250 21,000

Capital Equipment Cost, or Cost per Animal (dollars) 100 Million 1,000 10,000 to 50,000

Equipment Maintenance Costs, or Keeping Cost per Animal (dollars) 100,000 10 2,500

Unit Cost per Protein (dollars per gram) 100 0.10 to 0.25 2 to 20

*100 kg of raw material per year Source: AviGenics www.avigenics.com

Costs for 100kg of monoclonal antibodies per year

Learning Outcomes

4.  To evaluate the ethical, safety and legal issues related to animal pharming

Issues

•  Animal welfare •  Use of unnatural means ethical •  Risk of food chain contamination •  Risk of gene transfer/spread safety

•  Patenting of animals legal

Two Sides of A Coin

1.  Pharming violates animal welfare 2.  Animal pharming should be discontinued because it

uses an unnatural method. 3.  Animal pharming risks contamination of food (e.g.

milk, meat, etc). 4.  Animal pharming risks the transfer or spread of genes to

other living organisms. 5.  Transgenic animals developed in pharming should be

patented. 6.  Animal pharming has more benefits than risks.