The T Cell Repertoire 
the bacterial toxins that cause the toxins to bind 
to MHC and V(8's. So far we have identified three 
sites, one that seems to be concerned with bind- 
ing to MHC and two that seem to be involved with 
VjS binding. 
Recently we identified the superantigen mole- 
cules made by mice. These turn out to be the 
products of viruses that, over the course of evolu- 
tion, have become integrated into mouse DNA. A 
similar virus is transmitted from mice to their ba- 
bies in milk, causing breast cancer. It is likely that 
T cell stimulation via the viral superantigen is an 
essential middle step in mouse breast cancer de- 
velopment. This odd interaction between vi- 
ruses, T cells, and various seemingly unrelated 
diseases may not be unique to mice. Currently we 
are trying to find out whether a similar scenario 
applies to some viruses in humans. 
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