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Team:Marburg/Results
From 2013.igem.org
PHAECTORY: An elegant tool for production and secretion of Hepatitis B antibodies 
To challenge PHAECTORY for the efficient antibody production and secretion we constructed a series of expression vectors consisting of the following parts: BBa_K1071001-BBa_K1071008. The algae Phaeodactylum tricornutum was transfected with these plasmids. Two genes, which encode for the Hepatitis B antibody, were placed under the control of nitrate-induciable promoters. Five different clones of PHAECTORY were grown to an optical density of 0.4 (OD600) in a nitrate-containing medium (Figure). In a next step, we wanted to analyse how much Hepatitis B antibody was secreted from the algae into the surrounding medium. For this purpose, intact cells were separated from the surrounding medium by centrifugation. Both, cell pellets and supernatants were analysed for the presence of Hepatitis B antibodies by Western blot analysis.
The Western blot analysis (Figure) shows that huge amounts of Hepatitis B antibodies were secreted into the medium. The positive signal in the cell pellet shows that antibody production by PHAECTORY was still in progress. Taken together, the amount of Hepatitis B antibodies in supernatant was significantly higher in the supernatant then in the cell pellet. This is the ‘proof of concept’ that PHAECTORY has not only the ability to produce high-value proteins (e.g. antibodies), but also secrets them in huge amounts into the surrounding medium. Therefore, PHAECTORY allows direct secretion of high-value proteins into the medium, and allows their easy purification with low effort and costs.
