Producing Humanized Therapeutics in Avian Egg White

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DESCRIPTION (provided by applicant): This phase II SBIR project will test the feasibility of producing large amounts of human monoclonal antibody into transchromosomic avian egg white. We will use a full length ovomucoid genomic locus expression construct created and tested in phase I, to drive expression of the monoclonal's heavy and light chain cDNA. Using these constructs we produced transgenic hens that expressed human monoclonal antibody into their egg whites. This antibody was purified and analyzed for antigen binding and effector function. The results of this analysis support the conclusion that the transgenic produced antibody exhibits antigen binding and effector function that is comparable to the same antibody produced in a mammalian cell culture. This phase II project will also utilize an improved gene delivery system to generate fully transchromosomic avian hens. We have recently generated transchromosomal founders that exhibit germline transmission of a 60MB artificial chromosome. The offspring of these birds contain single copies of the artificial chromosome in every cell. This represents a breakthrough in avian transgenesis which to this point has been restricted by the limited payload capacity of retroviral-mediated methods. We will utilize this improved avian transgenisis technique to deliver the two ovomucoid-based human monoclonal antibody expression vectors developed in phase I to stage I embryos. Transgenic human monoclonal antibody from GO, G1 and G2 birds will be analyzed for expression level, purified and characterized for bioactivity and glycosylation. We anticipate that the G2 production flock will be able to supply sufficient human monoclonal antibody to proceed to clinical trials.