Determination of i-Antigens
Injection of paramecia into rabbits produces antiserum that reacts with immobilization antigens, or i-antigens, of Paramecium. In this chapter we will see how the story of the antigens has developed over the years. Now that the proteins and the genes that code for them have been identified and sequenced, we have a different perspective on the i-antigens, and a different way of approaching the problems today compared with what was done formerly. But when the story began we were primarily dependent on the techniques of genetics and immunology for our information. For instance, the differences between the B protein in stock 51 and that in stock 29 were impossible to determine at that time because no existing serum was able to tell one from the other. But now we can simply look at the gene sequences and compare them. In the following pages we try to present the development of our knowledge of the i-antigens in the way it actually occurred, that is, chronologically, for research on the antigens began long before molecular biology became important and James Watson had even been born.