While details of the vendor contract were undisclosed, US-PharmaTechnologist.com understands recombinant Protein A is used in the manufacture of monoclonal antibodies, one of the fastest growing classes of drugs in the biopharmaceutical industry. Repligen is the largest supplier of recombinant protein A, and first started producing it in 1982. Repligen president and chief executive Walter Herlihy said: "Entering this agreement is consistent with our continued commitment to be the world's leading supplier of Protein A used in the production of monoclonal antibodies. We anticipate continued robust growth of the monoclonal antibody market, which in turn will drive increased demand for products based on Protein A." Applied Biosystems declined to comment on the deal when contacted. Protein A is a cell wall protein in Staphylococcus aureus bacteria, which has binding properties for immunoglobulin-G (IgG) from a variety of mammalian species. Protein A also exhibits some binding to immunoglobulin-M and immunoglobulin-A. Recombinant Protein A is produced in E.coli through the expression of a modified Protein A gene. Protein A has the ability to be coupled to a variety of molecules including, enzyme markers, fluorescent dyes and radioactive iodine. The use of recombinant protein biological drugs has been growing at a speed double that of the pharmaceutical market, with a market value worth $50bn in 2005. In terms of monoclonal antibodies, there are currently 18 that have received regulatory approval, while more than 150 products are in various stages of clinical development. The worldwide revenues from this class of drug exceeded $20bn in 2006 and are forecast to exceed $30bn in 2010, following advances in cancer treatment. Monoclonal antibodies (MAbs) got their name because they are produced from a single type of immune cell. The antibodies bind to a specific known target and so can be used as a research tool to detect and purify that substance, for example in target validation. They can also be used clinically to deliver drugs to specific disease-related targets such as cancer tumor cells. MAbs are produced by inducing an immune response in animal cells, typically from a mouse. First-generation MAbs were limited by side effects and a tendency to lose efficacy over time. Since then, there has been a progressive effort by scientists to make the antibodies more human culminating in the generation of genetically engineered mice that produce fully-human antibodies. Late last year, Applied Biosystems introduced a new software tool that aimed to simplify DNA methylation research aiding scientists to further their understanding of this process in the genetic basis of complex diseases, such as cancer.