What attracted me to immunology was that the whole thing seemed to revolve around a very simple experiment: take two different antibody molecules and compare their primary sequences.

The study of the amino acid sequence around the disulphide bonds of the immunoglobulins was my own short-cut to the understanding of antibody diversity.

I wasn't a particularly brilliant student, but on the other hand, I was very active in Student Union affairs and in student politics.

Back in 1962, when I had by accident become the supervisor of Roberto Celis in Argentina, it occurred to me that antibody diversity might arise from the joining by disulphide bridges of a variety of small polypeptides in combinatorial patterns.

As we returned to Argentina, I started seriously to work towards a doctoral degree under the direction of Professor Stoppani, the Professor of Biochemistry at the Medical School.

When an animal is infected, either naturally or by experimental injection, with a bacterium, virus, or other foreign body, the animal recognises this as an invader and acts in such a way as to remove or destroy it.