When CTLA-4 interacts with B7 molecules it induces the apoptosis of T cells, then how it is possible that all lymphocytes will not die? CTLA-4 has higher affinity than does CD28, then it shoud induce the death of lymphocytes`???? And also... how is CTLA-4 related to autoimmunity? How the mechanism will develop and what part plays CTLA-4 in it? Can anyone tell?

Can you provide literature evidence of your statement: "When CTLA-4 interacts with B7 molecules it induces the apoptosis of T cells . . ."?