The immunogen was designed to raise an antibody against mouse Dppa4. However, the antibody does not recognise a band of the expected size of Dppa4 in the mouse cell lysate tested. This may be because Dppa4 is not expressed in sufficient amounts for detection by Western Blotting in those cells. The immunogen also contained a sequence of 12 amino acids found in human Dppa4. The antibody recognises a band of approximately the expected size of Dppa4 in human embryonic stem cell lysate. Additionally, the immuogen contains a sequence of 12 consecutive amino acids which are found in human Dppa2 and a sequence of 13 amino acids of which 11 are found in mouse Dppa2. Therefore, it cannot be ruled out that the antibody recognizes Dppa2.