My insistence, as I said, on the class I and class II was more than just coming up with something different than the others.  But in my view it was always... the H2 was complex but which had a certain unifying principle, and the class I class II was supposed to reflect that. Since similar complexes were then discovered in other animals and including humans, the question was... and they were named by different names in each of these animals, HLA in humans, B in the chicken and many different names in other animals... there was a need for a name that would include all these different systems in different animals, and the name major histocompatability complex then came to be used by most people and is used to this day and got into textbooks so this is what I am going to use from now on, MHC, major histocompatability complex.

So, for me the MHC was class I and class II and the question was still not answered however, what were IR1 genes? So in my opinion we detected IA were IR1 genes product. Not everybody agreed with that. Just on the side, it turned out to be actually correct, this was the IR gene product, but one could argue that they are two closely linked loci. One is the IR1 and I is the other and they have otherwise nothing to do with each other. We could not rule out that possibility. It just seemed to us simpler to assume that they are single locus and circumstantial evidence could be used to argue that way. Namely, they were both involved in immune response, it was just different forms of immune response. But nevertheless, it was not clear what the IR... why do they and how do these IA antigens, class II antigens, determine whether there is a low or high response to let's say TGALs and synthetic polypeptides or some other antigens. So how do these antigens actually determine that? Nobody had really any good suggestion. It was very difficult to come up with an idea that would really explain all the phenomena and all the data that had been accumulated, until in 1974 Rolf Zinkernagel and Peter Doherty published a paper in Nature, which to me came really like lightening out of the blue, and I think to many others, in which they showed that the response against viruses... so if you infect a mouse with a virus, the immune system reacts against the virus and virally infected cells, and that reaction is against the antigen of the virus but at the same time it is against the H2. So, there is a dual recognition. The immune system recognises two things. One was the foreign antigen and one was the H2... its own H2.