Les prot�ases chez les helminthes

Abstract

-Proteases in helmintic parasites. Proteases catalyse the cleavage of internal peptide bonds within peptides and proteins. They are classified into four major classes and are involved in a broad range of eukaryotic processes. Proteases have also been found to play a number of critical roles in the virulence of pathogenic agents, particularly of nematode parasites. Parasitic proteases are involved in different aspects of host-parasite interactions. They facilitate the invasion of host tissues and allow nutrition as well as the survival of the parasite in its host. Proteases also participate in the parasite's evasion from the host's immune response. The functional diversity and complexity of these enzymes are described in this review, with a particular focus on the principally identified proteases of four helminths: Schistosoma sp., Fasciola sp., Taenia sp. and Haemonchus sp. Some of these proteases, especially the cysteine proteases secreted by the parasitic trematode Fasciola hepatica, have been successfully tested in experimental immunodiagnosis. Proteases identified in different parasites are currently under study for a use as recombinant vaccines. In this respect, proteases are proposed as major potential targets for immunotherapy and chemotherapy against parasitic diseases. protease / virulence / helminth / therapy / vaccinationRésumé -Les protéases catalysent le clivage de liaisons peptidiques internes au sein de peptides et protéines. Classées en quatre grandes familles, ces enzymes sont impliquées dans de nombreuses fonctions des cellules eucaryotes. De plus, elles jouent un rôle critique dans la virulence des pathogènes et plus particulièrement des parasites. Elles interviennent à différents niveaux de l'interaction hôte-parasite. Elles facilitent la pénétration du parasite au sein de l'hôte et y assurent sa nutrition ; elles participent également à l'échappement du parasite vis à vis du système immunitaire de l'hôte. La diversité et la complexité fonctionnelle de ces molécules sont illustrées dans cette revue qui décrit les principales protéases identifiées chez quatre helminthes : Schistosoma sp., Fasciola sp., Taenia

Transcripts analysis of the entomopathogenic nematode Steinernema carpocapsae induced in vitro with insect haemolymph

“…Serine proteases are the major proteolytic enzymes expressed by parasitic nematodes and are frequently suggested to be involved in host–parasite interactions [45]. …”

Serine Protease-mediated Host Invasion by the Parasitic Nematode Steinernema carpocapsae

“…The relevance of these proteases to the parasitic process is supported by the fact they have been implicated as the most relevant antigens to protect against some nematode infections in vertebrates (41). Among expressed proteases, serine proteases are the most represented in nematode ESPs (13). In fact, they were identified in ESPs from Ancylostoma caninum, T. spiralis, and T. pseudospiralis (41)(42)(43).…”

Serine protease activity demonstrated in the larval stage of the pentastomid Linguatula serrata

“…According to the inhibition experiment, the 75-kDa peptide was classified as a serine protease. Of interest, serine proteases have been identified as important virulence factors in some pathogens including Schistosoma mansonii cercariae, Taenia saginata onchospherae (Trap and Boireau 2000), and Oestrus ovis larvae (Tabouret et al 2003). To elucidate if the 75-kDa enzyme of L. serrata plays a role in degrading proteins present in the direct environment of larvae, degradation of collagen was analyzed after incubation with L. serrata in vitro-released products.…”

“…It has not yet been demonstrated that mechanisms associated with the pathogenesis of L. serrata involve the presence of proteolytic enzymes. Given that central roles have been proposed for proteases in the virulence of pathogenic agents, such as facilitating the invasion of host tissues, nutrition, and host's immune response evasion (Trap and Boireau 2000), the objective of this study was to obtain and analyze the activity of larval in vitro-released products against type I collagen and to determine the biochemical class of the proteases involved in this mechanism.…”