Sensitivity of veiled (dendritic) cells to cyclosporine.

The effect of cyclosporine (CsA) on dendritic cell function was tested by pulsing rabbit veiled cells (VC, the "dendritic" cells from the afferent lymph) with the drug. This treatment inhibited their capacity to enhance proliferative responses of autologous peripheral blood lymphocytes to the mitogen concanavalin A. The concentration of CsA required to produce inhibition varied from one rabbit to another and ranged from 5 to 100 ng/ml. The degree of inhibition was greater under conditions in which the normal VC were more effective. Addition of further untreated VC restored the response, but this restoration was incomplete under some culture conditions. Pulsing peripheral blood mononuclear cells (PBM) with CsA also produced a reduction in the stimulation by Con A, and the response was not restored by addition of normal VC. The experiments did not distinguish whether the effect of CsA was directly on dendritic cell function or via a secondary effect of "presentation" of CsA to lymphocytes by the dendritic cells.