we propose that these effects occur by the following mechanisms : ( 1 ) the absence of intrathymic class ii antigens results in deficient production of cd4+ cells , ( 2 ) the cd4+ cells that do emerge from the thymus do not undergo postthymic maturation into cd4+hb11- cells with helper capabilities , and ( 3 ) the absence of cd4+hb11- effector cells results in abortive development of suppressor cells involved in feedback suppression .
C0019630
class ii antigens
C0039215
cd4