title: Immune defence mechanisms of triatomines against bacteria, viruses, fungi and parasites.
abstract: Triatomines are vectors that transmit the protozoan haemoflagellate Trypanosoma cruzi, the causative agent of Chagas disease. The aim of the current review is to provide a synthesis of the immune mechanisms of triatomines against bacteria, viruses, fungi and parasites to provide clues for areas of further research including biological control. Regarding bacteria, the triatomine immune response includes antimicrobial peptides (AMPs) such as defensins, lysozymes, attacins and cecropins, whose sites of synthesis are principally the fat body and haemocytes. These peptides are used against pathogenic bacteria (especially during ecdysis and feeding), and also attack symbiotic bacteria. In relation to viruses, Triatoma virus is the only one known to attack and kill triatomines. Although the immune response to this virus is unknown, we hypothesize that haemocytes, phenoloxidase (PO) and nitric oxide (NO) could be activated. Different fungal species have been described in a few triatomines and some immune components against these pathogens are PO and proPO. In relation to parasites, triatomines respond with AMPs, including PO, NO and lectin. In the case of T. cruzi this may be effective, but Trypanosoma rangeli seems to evade and suppress PO response. Although it is clear that three parasite-killing processes are used by triatomines - phagocytosis, nodule formation and encapsulation - the precise immune mechanisms of triatomines against invading agents, including trypanosomes, are as yet unknown. The signalling processes used in triatomine immune response are IMD, Toll and Jak-STAT. Based on the information compiled, we propose some lines of research that include strategic approaches of biological control.
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina,Universidad Nacional Autónoma de México,Circuito Interior,Avenida Universidad 3000,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: A L
authors.initials: AL
authors.lastname: Flores-Villegas
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina,Universidad Nacional Autónoma de México,Circuito Interior,Avenida Universidad 3000,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: P M
authors.initials: PM
authors.lastname: Salazar-Schettino
authors.affiliation: Departamento de Ecología Evolutiva,Instituto de Ecología,Universidad Nacional Autónoma de México,Apdo. P. 70-275,Circuito Exterior,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: A
authors.initials: A
authors.lastname: Córdoba-Aguilar
authors.affiliation: Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: A E
authors.initials: AE
authors.lastname: Gutiérrez-Cabrera
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina,Universidad Nacional Autónoma de México,Circuito Interior,Avenida Universidad 3000,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: G E
authors.initials: GE
authors.lastname: Rojas-Wastavino
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina,Universidad Nacional Autónoma de México,Circuito Interior,Avenida Universidad 3000,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: M I
authors.initials: MI
authors.lastname: Bucio-Torres
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Medicina,Universidad Nacional Autónoma de México,Circuito Interior,Avenida Universidad 3000,Ciudad Universitaria,04510,Coyoacán,Distrito Federal,México.
authors.forename: M
authors.initials: M
authors.lastname: Cabrera-Bravo
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology*; D005658:Fungi / Q000276:immunology*; D006790:Host-Parasite Interactions; D054884:Host-Pathogen Interactions; D007304:Insect Viruses / Q000276:immunology*; D014225:Triatominae / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology / Q000821:virology
keywords: Triatomine; antimicrobial peptides; haemocyte; nitric oxide; pathogens; phenoloxidase