The HOD antigen, specifically the N-terminal portion of OVA, contains OVA323-339, an epitope recognized by CD4+ T cells from T cell receptor (TCR) transgenic OTII mice (20); and, adoptive transfer of CD4+ OTII T cells, thereby circumventing T cell tolerance, into HOD animals stimulates autoreactive B cells to secrete autoantibodies against HOD RBCs (16). The gene discussed is CD4; the disease is hypopigmentation, organomegaly, and delayed myelination and development.