It is not uncommon to have heard about genetically modified or engineered organisms (GMO/GE) in regards to the world’s food supply. However, as it turns out, these science-lab creations are starting to have a significant impact on our healthcare system. For years, humans have understood the need for certain proteins as treatments for various ailments. Most commonly, we think of insulin in the treatment of diabetes, or the existence of plasma donation for the purpose of transfusion. While we know these biological needs exist, most people never consider how doctors and pharmacies attain these products when in shortage. Traditionally, scientists have used bacteria or other mammals as producers of medical proteins (3). However, with ever increasing demands, we are now expanding the field of protein pharmacology into the agricultural realm (5).
Before going into details about the potential benefits and risks of the use of GE plants for use in pharmaceutical production, let us establish the reason why the current system is not maintainable. Currently, many labs use bacteria or other living creatures in order to harvest medical proteins (5). One common example is the harvesting of insulin from bovine or porcine hosts. In these cases, the pancreas of livestock will be removed from the carcass after slaughter and will be separated from other substances until purified insulin remains. It is easy to see how animal enthusiasts would disapprove of this practice. Due to complaints of animal welfare, the first recombinant human insulin was produced in a culture of E. coli bacteria in the mid-80’s (7).
The question then would be asked, why not make all medical proteins in bacterial vectors? As was soon discovered after recombinant protein technology was utilized, there are unique challenges involved in bacterial protein harvesting as well. For example, just as mammals can carry pathogens, so can bacteria. While we would like to believe that scientists can completely isolate one single type of molecule, it is incredibly difficult to remove all traces pathogen or toxin from a bacterial cell culture. The risk of pathologic contamination proves to be significant enough that an alternative source of proteins has been sought after. In contrast to mammals and bacteria, plant protein suspensions have never been documented to transmit pathogens to humans, giving them an obvious advantage (2,5).
Another cause to consider in regards to why the current system is not maintainable is to look at current costs. With mammalian and bacterial subjects, it is clear that lab space is a strong limiting factor. Likewise, farmland for raising livestock is significantly less cost-efficient than the rearing of agriculture. As will be detailed later, agriculture based medical proteins may also need significantly less laboratory manipulation, further cutting down on time and costs (6).
It has been sufficiently supported that plants are a possible host for the creation of medicinal proteins. Throughout study into this field, it is also apparent that the most cost-efficient plants in which to produce these proteins are common food crops, such as corn and soybeans. With this in mind, the problem of crossbreeding between “normal” and GE crops comes into question. Currently, due to limited knowledge on the full range of effects of these GE plants during oral consumption, it is standard to eliminate the issue of crossbreeding by two main measures. In general, genetically modified crops for use in pharmaceuticals are grown in geographical locations where the crop in question is not normally present (5). Secondly, it is possible to virtually sterilize the plants by a process called “detassling,” which removes the pollen in the plants, preventing any unwanted cross-pollination.
While mentioning the process of pollination, it is important to address a second concern with the overall effect of GE crop usage. Due to limited knowledge on the subject, it is unknown how these modified plants may affect other species, such as bees and butterflies specifically. While there is not enough research to definitively say insects cannot be harmed by GE crops, it is understood that the majority of these medical proteins are highly species specific. Also, if the proteins are ingested by insect or other animals, it is thought that the normal acidity of the stomach would be enough to denature the protein, rendering it nonfunctional (5).
At this point, a clear purpose for the production of plant sourced medical proteins has been established. However, the question remains, will it work? There is no reason to think that a purified protein from crops would be any less effective than the same protein produced by current methods. However, some scientists propose that these proteins may not need to be isolated if they could be ingested orally instead. They propose that oral administration of proteins would be more cost effective, due to decreased processing, along with an increased level of protein stability, as there would be no need for refrigeration if purification was bypassed (1,4).
Now, it is helpful in knowing the different ways in which plant produced proteins are already being used in medicine. Currently, it is well known that plants can be used to produce antibodies against an antigen of choice. Commonly, these may be antibodies that are given to persons with various immunodeficiency conditions. Likewise, there is continuously advancing research in monoclonal antibody therapy as a method of identifying cancer cells, leading to more specialized treatment (5).
One additional application for crop produced medical proteins is their potential use in producing both single and multi-component vaccines. With the possible introduction of protein-based vaccines in a specially raised food supply, it is possible to increase rates of vaccination to people in rural areas, where traditional medical care may not be present (6). Additionally, an oral vaccine would decrease non-compliance rates of vaccination in developed countries (2,5).
Overall, is it important to notice the need for an increased production of medicinal proteins. While some may be skeptical of the risks associated with the use of genetically modified plants, it is also evident that there are many precautions in place to limit negative effects on the environment or other living creatures. With the possibility of advancing cancer treatment, along with potential increase in vaccination of diseases such as rabies, hepatitis B, type 1 diabetes, and some varieties of HIV-1, this venture appears to be a worth-while investment in the future of modern medicine (3).
- Carol O Tacket, Hugh S Mason, A review of oral vaccination with transgenic vegetables, In Microbes and Infection, Volume 1, Issue 10, 1999, Pages 777-783, ISSN 1286-4579, https://doi.org/10.1016/S1286-4579(99)80080-X.
- Heribert Warzecha, Hugh S. Mason, Benefits and risks of antibody and vaccine production in transgenic plants, In Journal of Plant Physiology, Volume 160, Issue 7, 2003, Pages 755-764, ISSN 0176-1617, https://doi.org/10.1078/0176-1617-01125.
- Joshi, Mukund & Singh, Kuldip. Transgenic plants as sole source for biopharmaceuticals. ResearchGate. November 2014. https://www.researchgate.net/
- Making “Edible Vaccines” in Plants, Federation of American Scientists, 2011, fas.org/biosecurity/
- QJM: An International Journal of Medicine, Volume 97, Issue 11, 1 November 2004, Pages 705–716, https://doi.org/10.1093/qjmed/hch121
- Stöger, E., Vaquero, C., Torres, E. et al. Plant Mol Biol (2000) 42: 583. https://doi.org/10.1023/A:1006301519427
- The, M J. “Human Insulin: DNA Technology’s First Drug.” American Journal of Hospital Pharmacy., U.S. National Library of Medicine, Nov. 1989, www.ncbi.nlm.nih.gov/pubmed/2690608.
