Eventually... so there were two nomenclatures and eventually an agreement was reached to... so we called it IR1 and they called it LNA and some other people introduced some other names. The agreement was reached to call the antigens altogether IA for I region was Associated. So it was in a way a compromise and then... Shreffler on the one hand and his co-workers and we on the other hand were continuing characterisation of the region that we identified. Shreffler and Chella David concentrated on the serological side of the problem and began to build what would be an analogue of the H2 chart identifying one antigen after the other and it turned out to be as complex as the K and D antigens, so they began to construct an IA chart of the same type, that means the distribution of the individual antigens among the different inbred strains.

We took a little bit different direction. I was tired of serology because of the experience that we had with the K D. In the end it turned out that all that was... looked so diversified [unclear] was part of the same molecule or two molecules and the individual antigens then became of little use except for a few that were very specific for the particular allele. The H2 from the beginning had always two faces, as Gorer discovered. One was the detection with antibodies, with the help of antibodies, something on the surface of the cells that would be the serological side of the studies, and the other was the graft rejection, in the case of Gorer, a tumor graft rejection.  But later it could be shown that any graft, as I think I also mentioned before, any graft would be rejected if there is a discrepancy between the donor and the host in the H2 antigens. So the second side... so there was serology on the one hand and the other hand was on the graft rejection method which Snell called histogenetic method, and so serelogical and histogenetic. So we concentrated on the histogenetic method, originally based on graft rejection but in the meantime several other assays became available which measured different sides, faces, sub faces of the so-called allograft reaction, that is the reaction against foreign cells... immune reaction against foreign cells. There was in the first place the graft... so-called the graft versus host reaction, which was discovered by Morten Simonsen, in which case normally you have a donor, you take tissue from a donor, you transplant it on the recipient and the recipient rejects it. That's the classical histogenetic test. Simonsen realized... discovered that when you take cells that contain a lot of lymphocytes, that is the cells that were involved in immune response and inject them into the mouse or chicken or some other animal, then these cells actually react against the host antigens, so a graft in this case is reacting against the host tissue rather than the host tissue reacting against the graft.  And you can measure this for instance by enlargement of spleen, which was where the injected lymphocyte usually homed... that they located themselves there, and we began to divide, expand and enlarged the lymph node... the spleen. The reaction is much more simpler... much more complex than this simple explanation, but in principle this is what causes the enlargement of the spleen. So by this assay you could measure histocompatability differences.