Polymorphonuclear leukocytes mediate the immune modulation of dendritic cells, increasing or decreasing its immunostimulatory capacity and expression of DC-SIGN

MAFFIA PAULO; AMIANO NICOLAS; GUERRIERI DIEGO; REITERI MACARENA; TATEOSIAN NANCY; CHULUYAN EDUARDO

Córdoba, Argentina.

Congreso; VII Latinamerican Congress of Immunology; 2005

ALAI

Dendritic cells (DC) are professional antigen presenting cells that play a critical role in the induction of acquired immune responses. The polymorphonuclear cells (PMNL) are the first cells that are recruited in the inflammatory focus. Previous studies in our laboratory showed that the incubation of DCs with PMN or culture supernatant (CS) derived from unstimulated or IL-8 stimulated PMN decreased allostimulatory ability of DCs. The effect was not due to PMN-induced DCs apoptosis, downmodulation of class I or II MHC, costimulatory or adhesionmolecules. Furthermore, PMN´s CS did not modify the DCs production of IL-10 or IL-12. However, it increased the expression of TGFb mARN and protein. However, other authors reported an induction of DC maturation by activated PMNLs and a decreased in DC-SIGN expression on the surface of the DCs. This molecule a C-type lectine expressed in vitro on monocyte derived DCs and in situ on DC subsets in the skin, mucosal tissues, tonsils, lymph nodes and splee. DC-SIGN plays an important role in many aspects of DC functions. In order to elucidate this, we investigated the effect of PMNL or their conditioned supernatants (CS) on DCs allostimulatory capacity orexpression of DC-SIGN. The incubation of DCs with PMN or culture supernatant (CS) derived from unstimulated or LPS stimulated PMN increased or decreased allostimulation ability of DC in accordance to the ammount of PMNLs used. And a decreased in DC-SIGN expression was seen in DCs treated with PMNLS CS, and this effect was mimic with an equivalent amount of Elastase.