We thought, the idea- the blame for that idea actually goes to Klaus because he was the first person- Rejewsky- he was the first person to propose it, was that there was an antigen bridge between T- and B-cell. T-cell recognised one part of a protein. B-cell recognised the other part. And when you worked with hapten protein conjugates, B-cells recognised the hapten and T-cells recognised the protein. Now, the fact that they recognised different determinants in that way, is very well established, and was originally discovered by Jale and Benacerraf, and has never been checked. And that's true. It was the bridge which- where we made a mistake. Quite an excusable mistake because- and it didn't take long, very long, to rectify. It turned out that T-cells and B-cells saw antigen, didn't see antigen in that way, that the B-cell which was making antibody against the DNP, against dinitrophenol group or potentially they they were taking up, would take up antigen. But instead of making a bridge with the T-cell with the DNP protein, it broke the protein up inside the cell and other bits of the protein then got exposed on the surface bound by MHC molecules, bound by Class 2 molecules, MHC Class 2 molecules which are the antigen presenting proteins which T-cells recognise.