The effect of secretory leukoprotease inhibitor (SLPI) on dendritic cells (DC) phenotype and function

30. REITERI, MACARENA; VILLALONGA, XIMENA; COSTA, M. JULIETA; MAFFÍA, PAULO; TATEOSIAN, NANCY; CHULUYAN, EDUARDO

Buenos Aires

Congreso; First French-Argentine Immunology Congress; 2010

SAI

Dendritic cells (DCs) are the main antigen presenting cells thatmediate the link between the innate and adaptive immuneresponse. In the tissues, the immature DCs are exposed to avariety of factors. SLPI is a serine protease inhibitor constitutivelyexpressed in the epithelial mucosal lining cells and itsexpression increases following an inflammatory stimulus. Theaim of the present study was to examine the effect of SLPI on immature DCs. For this, DCs were generated from peripheralblood monocytes in the presence of IL-4 and GM-CSF. DCs wereincubated 48 h with rhSLPI (4 μg/ml) or control buffer and theexpression of surface molecules and apoptosis were analyzedby flow cytometry. Also, lymphocyte proliferation induced bySLPI-treated DCs or untreated DCs was analyzed by 3H-Tymidineincorporation. SLPI-treated cells showed an increase ofCD83 (8 ± 2%, p<0.05), but not MHC class I and II, CD40, CD80and CD86. Basal apoptosis of immature DCs was low (12 ± 3%).When DCs were treated with SLPI, early apoptosis was significantlyincreased (SLPI: 20 ± 4%, p<0.05). The effect of SLPI onDCs apoptosis was not observed with heat denatured SLPI. Furthermore,SLPI treated-DCs showed higher lymphocyte allogeneicproliferative ability compared to untreated DCs (Control:23709 ± 2033 cpm; SLPI: 40726 ± 5733 cpm, p<0.05). The effectof SLPI-treated DCs on lymphocyte proliferation was dose dependentand it was not observed with heat denatured SLPI.These results demonstrate that SLPI modify the phenotype andfunction of immature DCs. Based on the CD83 expression, theincrease in apoptosis and the proliferation, it is probably thatSLPI promote the maturation of DCs.