Maintenance of self tolerance in CD4+ T lymphocytes by antigen presentation on resting B cells--a hypothesis.

Self tolerance in the immune system is established by clonal deletion or induction of clonal anergy in immature lymphocytes. In addition, repair mechanisms for self tolerance working in the mature immune system may exist to take care of self-reactive lymphocytes eventually leaking through the central mechanisms. Two possible repair mechanisms for self tolerance, both capable of self/nonself discrimination, are discussed in this article. The first is the so-called veto function, which works on CD8+ T cells. The second is a new hypothesis suggesting that CD4+ T cells may be anergized by recognizing antigen on self-specific, anergic B cells.