The moss bioreactor
Jason Halm posted to the Biotech news thread:
Message 19817588
Further information about this method to produce proteins can be found at Greenovation's website.
greenovation.com
In July of last year they announced the first successful delivery of a humanized antibody:
FIRST ANNOUNCEMENT OF THE SUCCESSFUL PRODUCTION
OF A THERAPEUTIC ANTIBODY IN MOSS (Physcomitrella patens)
14th July 2003
London/Freiburg - Dr Sabrina Wagner (CEO, greenovation Biotech) and Dr Tarran Jones (CEO, AERES Biomedical) announced today that greenovation (Freiburg, Germany) and AERES (London, UK) had successfully completed a major milestone in the development of a new production system for the manufacture of therapeutic antibodies in moss. Using a humanised antibody (ABC-48) currently in pre-clinical development at AERES for the prevention of deep vein thrombosis, scientists at greenovation have successfully expressed the humanised antibody, which was secreted into the medium. The secreted ABC-48 antibody was shown to be correctly assembled and displayed normal binding activity to its natural ligand.
"Producing ABC-48 in a moss bioreactor offers the potential to produce this novel humanised antibody, and other therapeutic antibodies as well, far more cost effectively than more traditional manufacturing routes, significantly reducing the overall cost of goods" said Dr. Tarran Jones, CEO of AERES Biomedical. "We are very pleased to have been able to participate in this successful collaboration with greenovation to develop this important new manufacturing strategy."
"The expression of a therapeutic monoclonal antibody in moss is a major milestone again confirming that this plant can produce a wide range of complex biopharmaceuticals. Moss is the only plant that allows humanisation of its glycosylation pattern. The moss protonema grows in a simple medium consisting essentially of water and some minerals, target proteins are secreted into the medium. This makes the system safe and significantly reduces costs for cultivation and purification" said Dr. Sabrina Wagner, CEO of greenovation Biotech. "The collaboration with AERES provides us with access to a therapeutic antibody and will allow both companies to fully capitalise on our production platform."
greenovation is a privately held biotechnology company based in Freiburg, Germany. The company was founded in 1999 as a university spin-off. Venture capital investors are Mediport Venture Fond II, Berlin, Seed Venture, Karlsruhe, and L-EA, Karlsruhe. greenovation's moss bioreactor is a major innovation in the manufacture of biopharmaceuticals including safety and cost advantages of plant-based systems and at the same time avoiding risks associated with environmental release. In co-operation with pharmaceutical companies greenovation develops the moss production strains for biopharmaceuticals.
greenovation's moss bioreactor is based on the fermentation of the moss protonema, Moss is the only known plant system which shows a high frequency of homologous recombination. This attribute allows for targeted gene insertion leading to the stable integration of foreign gene(s). Another important aspect of the moss system is that it can be manipulated to make targeted gene knockouts. Homologous recombination is used to knock out plant-specific glycosyltransferases, which allows humanisation of the glycosylation pattern. Time-to-market is comparable to traditional systems. A transient expression system is used for feasibility studies within weeks and stable production strain development takes 4 to 6 months. Cultivation in suspension allows up-scaling of the photobioreactors up to several 1000 L. Through photoautotrophic cultivation it requires a simple medium, which is safe and together with secretion of the heterologous protein greatly facilitates downstream processing.
AERES Biomedical Ltd. Is a privately-owned drug development company which has been active in the development and exploitation of antibody humanisation since 1988. AERES is now applying its expertise to the development of humanised therapeutic antibodies both in-house and with its collaborative partners. Over the past 15 years, AERES scientists have radically improved this technology and developed a portfolio of related antibody engineering skills. With nearly 30 successful collaborative R&D programmes with the biopharmaceutical industry, which has enabled at least 7 humanised antibodies to enter clinical trials, AERES has established a world-wide reputation for its expertise in antibody humanisation. In addition, AERES has a significant track record of success in maximising the expression of antibody genes in mammalian cells. As a consequence, AERES is able to provide its commercial collaborators with drug candidates that move rapidly through clinical development with an increased probability of reaching the market.
ABC-48 is a humanised antibody which targets P-selectin, a glycoprotein found on the surface of activated platelets and vascular endothelial cells. This molecule mediates the interaction between platelets and leukocytes and plays a key role both in the development of blood clots (thrombosis) and also in the migration of leukocytes out of the blood vessels during inflammation (extravasation). Blocking the activity of P-selectin has been shown to inhibit both these processes and as such it has considerable potential to be applied in a wide range of indications in thrombosis and inflammation. Through the selective targeting of P-selectin it has been demonstrated that ABC-48 is able to inhibit the coagulation cascade in the absence of the bleeding risk normally associated with anti-coagulants. In addition, as a humanised antibody, a single dose is expected to be able to provide protection from deep vein thrombosis (DVT) for several weeks. Whilst the market for drugs aimed at preventing DVT alone is currently in excess of US$1 billion, ABC-48 also offers therapeutic potential in a number of other indications including the prevention of both reperfusion injury and neo-intimal restinosis, and as an adjunct to thrombolytic therapies. ABC-48 is currently in late pre-clinical development for the prevention of DVT following surgery and is expected to enter clinical trials in 2004/5.
ENDS
Notes to Editors
Moss protonema is a green multicelular filament consisting of two cell types, chloronema and caulonema. In nature spores germinate to grow the protonema. In the laboratory the protonema grows from protoplasts, which are used for transformation. Moss protonema is a fully differentiated tissue and can be cultivated in liquid medium.
Homologous recombination: Two DNA molecules that are homologous (i.e. share long stretches of essentially the same sequence) recombine resulting in sequence integration, exchange or deletion. Highly efficient recombination, as it occurs in moss, yeast, and embryonic stem cells of mice, is used to target gene insertions and to knock out specific genes.
Glycosylation patterns, i.e. the sugar structures on proteins, differ between humans and plants only slightly. Plants show two additional sugar residues, which are associated with allergenic potential. Knock-out of the relevant xylosyl- and fucosyltransferases results in complete removal of these two residues from the gylcosylation pattern in moss, so that allergenic effect of these sugars can no longer occur.
Antibody humanisation, also known as CDR-grafting (CDR is a synonym for complementarity determining region) was first invented at the Medical Research Council (MRC) Laboratory of Molecular Biology in the UK by Dr. Greg Winter and patented by the MRC in the late 1980's. This humanisation technology was originally developed to address the problem of the HAMA (Human Anti-Mouse Antibody) response, which had effectively prevented the therapeutic use of mouse monoclonal antibodies up to this time.
CDR-grafting involves the genetic transfer of mouse CDRs (which are responsible for antigen binding) into human frameworks of a variable region. A variable region is one domain of a immunoglobulin chain, a whole antibody itself comprising of one light and one heavy immunoglobulin chain. An important aid to the process of humanisation is molecular modelling, which allows the 3 dimensional structure of the antibody to be carefully analysed and key mouse framework residues important for antibody function to be identified for preservation in the humanised antibody.
DVT is a leading cause of morbidity and mortality in hospitalised patients. Common risk factors for developing DVT include prolonged immobility (for example in air travellers suffering from "economy syndrome") obesity, major surgery trauma, cardiac-related medical conditions and age (over 40yrs). In the USA an estimated 450,000 cases of DVT occur annually, many of which progress to pulmonary embolism (PE), which in itself results in 240,000 deaths a year, including 60,000 which are directly attributed to the consequences of DVT. Additionally about 30-60% of patients with DVT develop a post-thrombotic syndrome resulting in long term complications such as chronic leg pain, oedema, skin pigmentation and ulceration. DVT is often clinically silent, with symptoms being manifested in only about 30% of cases, and is only detected with difficulty. Therefore, prophylaxis is the most effective strategy.
AERES Biomedical Ltd. is a UK based biopharmaceutical research and development company created to:
• Enable the biopharmaceutical industry to exploit AERES expertise and skills in antibody humanisation, engineering and expression.
• Identify, in-license and develop its own antibody-based therapeutic agents through to proof of principle before securing commercial alliances with pharmaceutical companies for their further development.
• Develop and improve its in-house antibody-based proprietary technologies to generate new drug candidates against novel targets.
greenovation.com |
