Entamoeba histolytica cysteine protease 2 (EhCP2) modulates leucocyte migration by proteolytic cleavage of chemokines.

Human amoebiasis is a disease produced by infection with the protozoan Entamoeba histolytica currently affecting many millions of people worldwide. Amoebic colitis is the most common clinical manifestation. Host protective immunity involves participation of both humoral and cellular responses. However, the mechanisms involved in immune evasion are not clear and remain under investigation. One of these mechanisms could be associated with the ability of parasite proteases to modulate or interfere with the inflammation process, which is initiated by expression of pro-inflammatory cytokines such as chemokines. To further clarify the potential role of cysteine proteases in modulating chemokine-mediated functions, we have analysed the ability of Entamoeba histolytica cysteine protease 2 (EhCP2) to have an effect on the chemotaxis of leucocytes by chemokine cleavage. We find that EhCP2 is capable of cleaving chemokines CCL2, CCL13 and CXCL8, and the resulting proteolysis products modulate the chemotaxis of leucocytes when compared to that induced by intact chemokine. Thus, the extracellular activity of the cysteine proteases affects chemokine-mediated responses and could be considered as part of the mechanisms used by Entamoeba histolytica to circumvent the host immune responses.