This project is about a theoretical model for development of autoimmune disease. The central point in this model is idiotype (Id) dependent T and B cell cooperation. B cells with idiotype sequence in their antibody (Id+ B cells) can present Id-peptides to Id specific T cells and thus receive help to produce antibodies, independently of the specificity of the antibody. In this way you can get production of antibodies that attack the body's own tissues.
Three experiments that test the model are described. In these experiments, Id+ B cells, Id specific T cells and rheumatoid factor (RF) B cells from transgenic mice were used. The RF producing B cells can get help from the Id specific T cells. Together, this set of three transgenic cells can induce RF production.
Results from the first in vitro experiment showed a high degree of accordance with the theoretical model: B and T cells were activated and proliferated. RF B cells produced RF.
In the second in vitro experiment, cell proliferation was studied specifically from day to day. We found activation of lymphocytes and production of blasts in addition to cell proliferation, mainly between days 1 and 3.
The third experiment, which was performed in vivo, showed negative results.
These experiments strengthen the theory that interactions between the three cell types lead to Id specific T-B cooperation, followed by RF production. However, we cannot say anything from these three experiments about the system´s properties in vivo, and whether this theory can explain the development of autoimmunity and autoimmune diseases.