Sox2, also known as SRY (sex determining region Y)-box 2, is a transcription factor essential for maintaining self-renewal of undifferentiated ES cells and is one of the key transcription factors used to reprogram mouse and human fibroblasts to a pluripotent state. Sox2 expressed in undifferentiated pluripotent stem cells and germ cells during development. Affinity purified rabbit anti-Sox2 antibody can be used to demonstrate pluripotency of ES and iPS cells. This antibody is a rabbit polyclonal antibody raised against an internal region of human SOX2.