Frank Macfarlane Burnet

The production of antibody is not the only, nor I believe the most important, manifestation of immunity, but for reasons both historical and of experimental convenience, antibody is likely to remain the touchstone of immunological theory.

Human insulin differs from other mammalian types by having a different C-terminal amino acid on the B chain. The immunological difference between beef insulin and human insulin, which is presumably responsible for the antigenicity of the former in some human beings, is thus limited to very a small portion of the whole molecule.