Excretory secretory products (ESP) from a helminth parasite induce apoptosis and confer anti-inflammatory properties to myeloid dendritic cells

CERVI LAURA; FALCÓN CRISTIAN; MOTRÁN CRISTINA

Rio de Janeiro , Brasil

Congreso; 13th International Congress of Immunology - IMMUNO RIO 2007; 2007

International Union of Immunological Societies, ALAI y Sociedade Brasileira de Imunologia

In infectious diseases, dendritic cells (DCs) are able to sense pathogens, integrate this information and regulate the quantity and quality of adaptive immune response. During its migration through the host, the helminth parasite Fasciola hepatica release different products which contact with immune cells, among which are DCs. In this work, we study the ability of ESP to modulate the activation of TLR-stimulated DCs and their effect on the induction of allogeneic T cell responses.  ESP affect the capacity of LPS-treated DCs to up-regulate the expression of CD40, CD80, CD86 being the highest effect on CD40 (from 56% to 7%) In addition, IL-12 and TNFa production were also diminished in ESP-LPS- treated DCs. ESP were also able to induce apoptosis of immature or LPS-mature DCs. CD40 down-regulation observed in ESP-LPS treated DCs, was not related to the diminished viability of DCs, since annexin-V (-),  7-AAD (-) DCs, also showed a marked diminution in this molecule. Exposure of DCs to ESP impairs the ability of immature or LPS-activated DCs to prime alloantigen specific T cell response and INFg production in vivo and in vitro. Our findings suggest, that ESP-DCs contact impairs the viability and function of these cells. This fact could be a strategy of the parasite to prevent the developing of an effector T cells response. Besides, the treatment of DCs with ESP could be exploited as a novel approach for down-regulating unwanted T cell response