TBPP_introduction to derivatives of plasma as therapeutics
without conclusion
without conclusion
Fichier Détails
| Cartes-fiches | 14 |
|---|---|
| Langue | English |
| Catégorie | Chimie |
| Niveau | Université |
| Crée / Actualisé | 27.12.2016 / 04.01.2017 |
| Lien de web |
https://card2brain.ch/box/20161227_tbppintroduction_to_derivatives_of_plasma_as_therapeutics
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most complex human-derived proteome containing other tissue proteomes as subsets. Collected in huge amounts for protein therapeutic products. Big diversity of proteins, difficult for isolation but isolation is important. Bright spectrum of molecular masses of proteins.
classical proteins secreted by liver and intestines. Immunoglobulins: unique class of proteins because of their complexity. Long distance receptor ligands: classical hormones. Local receptor ligands: cytokines and others. Temporary passengers: lysosomal proteins. tissue leakage products: enzymes etc.. aberrant secretions: from tumours and other diseased tissues. foreign proteins: infectious organisms or parasites
Cohn method: 5 crude plasma fractions (1. fibrinogen, 2. antibodies, 5. albumin). Residual impurities depending on fractionation conditions. Subfractions: EtOH fractionation or alternate processes.
in special cases. Immunized for anti-D/tetanus/rabies for immune globulin. Screened for: CMV, measles, zoster, hepatitis A and B
more than 1/2 from US. Source Plasma: >65%, FDA-licensed, plasma obtained by apheresis, red cells returned to donor, more frequent donations possible (easier for the body to replace only the proteins, 1 donation per week/two weeks), 600-800ml plasma per donation, higher in FVIII. Recovered plasma: <35%, plasma remaining after whole blood collection used to make red cell concentrate, 450ml whole blood and max. 250ml plasma per donation, longer donor frequencies: 3 months, higher in immune globulins.
1. donor selection, 2. donation and plasma pool testing, 3. manufacturing process to reduce potential pathogens, 4. vigilance (screening)
risk goes down dramatically with each step, many factors for risk definition.
donor health, plasma safety. Diseases transmissible by blood: HIV, Hepatitis A/B/C, parvovirus B19
donors with high-risk behaviour are excluded. Donor education, questionnaire, physical examination, confidential self-exclusion
mandatory serological testing on all donations: HIV-1/2 antibodies, Hepatitis C antibodies, Hepatitis B surface antigen. NAT/nucleic acid testing on plasma donations (mini-pools): HIV-1 RNA, HCV RNA, HBV RNA, HAV RNA, B19V DANN
serologic tests depend on formation of antibody/presence of antigen, time needed to become detectable. NAT detects the specific nucleic acid sequence specific to the pathogen (more sensitive). Also a in-process control
purification and concentration of plasma proteins. Precipitation and separation: cryoprecipitation, cold ethanol fractionation, salting out, polyethylene glycol, fatty acid/alcohol. Chromatography: ion exchange, affinity, hydrophobic interaction. Target protein or waste fractions are washing out. Virus reduction steps: inactivation --> heat treatment (pasteurization, dry or vapor heat treatment), chemical treatment (solvent detergent, caprylate, low pH), virus filtration (also nanofiltration, only antibodies can get through the pores, depending on viral size). target of inactivation: disruption of virus envelope
physical differences. The larger the filter pole the easier is the entrance of a virus by nanofiltration. Problem: variation and different/similar sizes of the plasma proteins
process validation studies: assure processes work as planned
choice of viruses for spiking: blood-borne/model viruses, effective/sensitive and reliable cell culture (virus should grow to high rate), seleceted viruses cover a wide range of physicochemical characteristics (DNA and RNA, enveloped and non-enveloped, large and small, low and high resistance). manufacturing simulation: scaledown models comparable to large scale processes, exhaustive analytics package to demonstrate biochemical comparability (similar to large scale, target protein intact).
