Regulation of expression of the ligand for CD40 on T helper lymphocytes.

摘要: Activated Th cells deliver contact-dependent signals to resting B lymphocytes that initiate and drive cell proliferation. Recently, a ligand for the lymphocyte membrane protein, CD40, has been identified delivers cells. A dimeric soluble form of CD40 was produced used further characterize regulation expression ligand. Expression rapidly induced after activation, its stability depended upon whether were activated with or plastic-bound stimuli. stimuli turned over cell-surface whereas exhibited more stable up 48 h. Removal from stimulus resulted in rapid turnover ligand, suggesting continuous stimulation could maintain expression. Ligation by also stabilize on surface. Both IL-2 transiently synthesized 1 12 h activation had similar kinetics synthesis. In Con A-activated newly an initial high (1.5 t1/2) 5 became (10-h t1/2). anti-CD3, biphasic except phase began significantly later. This delay allow time assemble associate other molecules thus become stabilized Newly appeared not be efficient delivering cell-dependent contact cells, implying need assembly accessory proteins. Regulation consistent all characteristics cell-delivered may contribute degree specificity responses.