In a 1974 paper on supergauge transformations in four dimensions, Wess and Zumino considered an extended supergauge group which contains the conformal group as a subgroup. An interesting thing about this supergauge group is that the group generators seem to be quantum analogues of what are known elsewhere as twistors.
Has this link ever been clearly explored in more detail in the meantime? I am aware that there has also been a supersymmetric version of twistor theory which establishes something resembling a suitable supersymmetric extension of classical twistor theory (also in the 1970s).
