Figure 5

Example of the IL-12 based screening. ES cells successfully transfected with a bicistronic construct expressing IL-12 40, secrete IL-12 p40 into the culture medium if the espression of this reporter protein is not repressed. ES colonies expressing IL-12 p40 are identified by ELISA using a small aliquot of culture medium, and subsequently tested by PCR. All standards, samples and controls were run in duplicate and mean adsorbance values calculated. Standard ranges between 2000–62 pg/ml; c = untransfected; b = blank.