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Quality and lifecycle management
Published in Sarfaraz K. Niazi, Biosimilars and Interchangeable Biologics, 2016
Prions come from transmissible spongiform encephalopathies (TSE) include scrapie in sheep and goats, chronic wasting disease in mule deer and elk, Bovine spongiform encephalopathy (BSE) in cattle, Kuru and Creutzfeldt-Jacob disease (CJD) in humans. The disease causing agents (prions) replicate in infected individuals generally without evidence of infection detectable by available diagnostic tests applicable in vivo. The major source of contamination of a recombinant product is the use of animal derived raw materials, which could harbor bovine prions (BSE agent). Currently, there are no assays that are sensitive or specific enough to test raw materials or sources, and the only reliable prevention is to include barriers, such as avoidance of animal or human raw materials (e.g., trypsin, serum, transferin, bovine/human serum albumin, protein supplements, and peptones). However, this is not always possible (e.g., in the propagation of cells for the establishment of cell banks) and inactivation and removal procedures during downstream processing become of interest. Milk is unlikely to present any risk of prion contamination. Filtration has proven efficient in the removal of prion particles, Thus, size exclusion partitioning of abnormal prion particles using normal flow filtration or tangential flow filtration resulted in significant reduction of the infectious agent. The most effective inactivation methods include chloride dioxide, glutaraldehyde, 4 M guanidium thiocyanate, sodium dichloroisocyanurate, sodium metaperiodate, 6 M urea, and autoclaving at 121 qC for 15 min of which several will not be suited if the target protein is present. Biological assays such as in vivo infection of susceptible animals are time consuming (months to years). They will not be of practical use in the test of biopharmaceutical products. The best semiquantitative biochemical assays include Western blot, Capillary immunoelectrophoresis, Conformation-dependent immunoassay, and dissociation-enhanced, time-resolved fluoroimmunoassay. The infectious dose is not known. Accept criteria must be decided upon on a case-by-case basis.
Biological Terrorist Agents
Published in Robert A. Burke, Counter-Terrorism for Emergency Responders, 2017
Mad cow disease (Bovine spongiform encephalopathy [BSE]) is a slowly progressive, degenerative, fatal disease affecting the central nervous system of adult cattle. There is a disease similar to BSE found in humans called Creutzfeldt–Jakob disease (CJD). A variant form of CJD (vCJD) is believed to be caused by eating contaminated beef products from BSE-affected cattle. To date, there have been 155 confirmed and probable cases of vCJD worldwide among the hundreds of thousands of people that may have consumed BSE-contaminated beef products. The one reported case of vCJD in the United States was in a young woman who contracted the disease while residing in the United Kingdom and developed symptoms after moving to the United States. BSE is not transmitted in cow's milk, even if the milk comes from a cow with BSE. BSE in cattle was first reported in 1986 in the United Kingdom. The exact origins of BSE remain uncertain, but it is thought that cattle initially may have become infected when fed feed contaminated with scrapie-infected sheep meat-and-bone meal (MBM). Scrapie is a prion disease in sheep similar to BSE in cattle. The scientific evidence suggests that the United Kingdom is the source of the outbreak. BSE outbreak in cattle then was expanded by feeding BSE-contaminated cattle protein (MBM) to calves. The definitive nature of the BSE agent is not completely known. The agent is thought to be a modified form of a protein, called a prion, which becomes infectious and accumulates in neural tissues causing a fatal, degenerative, neurological disease. These abnormal prions are resistant to common food disinfection treatments, such as heat, to reduce or eliminate their infectivity or presence. Research is ongoing to better understand TSE diseases and the nature of prion transmission. BSE is a transmissible spongiform encephalopathy (TSE), a family of similar diseases that may infect certain species of animals and people, such as scrapie in sheep and goats, BSE in cattle, chronic wasting disease (CWD) in deer and elk, and variant Creutzfeldt–Jakob disease (vCJD) in people. To date, there is no scientific evidence that BSE in cattle is related to CWD in deer and elk. FDA is working closely with other government agencies and the public health community to address CWD in wild and domesticated deer and elk herds. Wildlife and public health officials advise people not to harvest, handle, or consume any wild deer or elk that appears to be sick, regardless of the cause, especially in those states where CWD has been detected. Both of those diseases are mentioned here because a terrorist could wreak havoc on the economy of countries and seriously affect the food supply by spreading these diseases among animals. In the case of mad cow disease, people could be affected as well.
Principles of risk decision-making
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Daniel Krewski, Patrick Saunders-Hastings, Patricia Larkin, Margit Westphal, Michael G. Tyshenko, William Leiss, Maurice Dusseault, Michael Jerrett, Doug Coyle
Prion diseases are caused by a misfolded form of the prion protein, which leads to neurodegeneration through propagation of the misfolded form within neural tissue. Fatal prion diseases have been described in multiple species, including scrapie in sheep, bovine spongiform encephalopathy (BSE) or ‘mad cow disease’ in cattle, chronic wasting disease (CWD) in deer and elk, and variant Creutzfeldt-Jacob disease (vCJD) in humans. Prion diseases may be transmissible between species: for example, BSE is thought to have originated from the inclusion of sheep offal in the diets of cattle in the United Kingdom, with consumption of beef containing the BSE agent leading to the development of vCJD in humans. The outbreak of the BSE epidemic in the UK in 1986 spread to other countries, and enormous negative socioeconomic impacts in BSE-affected countries (Leiss et al. 2010). Human prion disease may be transmitted by blood transfusion. Infectious prion proteins were detected in fertility drugs from human urine, presumably arising from donors with asymptomatic vCJD (Van Dorsselaer et al. 2011). There remain concerns regarding species transmission of CWD from deer and elk to other cervid species, including caribou (Haley and Hoover 2015). There is also increasing evidence that propagated protein misfolding plays a role in other neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis (Herms and Dorostkar 2016). At present, there are no effective medical interventions for prion diseases, although a promising vaccine against CWD is currently under development (Goñi et al. 2015).