Anti-CD4 mediates clonal anergy during transplantation tolerance induction

Depletion of CD4+ cells using anti-CD4 monoclonal antibodies leads to allograft tolerance. Here we show that anti-CD4-mediated tolerance to pancreatic islets of Langerhans transplanted from an A/J (IEk) donor to a diabetic C57B1/6 (B6) (IE-) recipient occurs in the absence of clonal deletion of the potentially IE-reactive V beta 11+ T cells. Instead, a state of clonal anergy is induced in both the CD4+V beta 11+ and CD8+V beta 11+ T cell subsets. This clonal anergy can be partially overcome in vitro by the addition of recombinant interleukin 2.