title: Triatoma infestansCalreticulin: Gene Cloning and Expression of a Main Domain That Interacts with the Host Complement System.
abstract: Triatoma infestansis an important hematophagous vector of Chagas disease, a neglected chronic illness affecting approximately 6 million people in Latin America. Hematophagous insects possess several molecules in their saliva that counteract host defensive responses. Calreticulin (CRT), a multifunctional protein secreted in saliva, contributes to the feeding process in some insects. Human CRT (HuCRT) andTrypanosoma cruziCRT (TcCRT) inhibit the classical pathway of complement activation, mainly by interacting through their central S domain with complement component C1. In previous studies, we have detected CRT in salivary gland extracts fromT. infestansWe have called this molecule TiCRT. Given that the S domain is responsible for C1 binding, we have tested its role in the classical pathway of complement activation in vertebrate blood. We have cloned and characterized the complete nucleotide sequence of CRT fromT. infestans, and expressed its S domain. As expected, this S domain binds to human C1 and, as a consequence, it inhibits the classical pathway of complement, at its earliest stage of activation, namely the generation of C4b. Possibly, the presence of TiCRT in the salivary gland represents an evolutionary adaptation in hematophagous insects to control a potential activation of complement proteins, present in the massive blood meal that they ingest, with deleterious consequences at least on the anterior digestive tract of these insects.
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Katherine
authors.initials: K
authors.lastname: Weinberger
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Norberto
authors.initials: N
authors.lastname: Collazo
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Aguillón
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: María Carmen
authors.initials: MC
authors.lastname: Molina
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rosas
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Jaime
authors.initials: J
authors.lastname: Peña
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Javier
authors.initials: J
authors.lastname: Pizarro
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Ismael
authors.initials: I
authors.lastname: Maldonado
authors.affiliation: Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile.
authors.forename: Pedro E
authors.initials: PE
authors.lastname: Cattan
authors.affiliation: Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Werner
authors.initials: W
authors.lastname: Apt
authors.affiliation: Programa Disciplinario de Inmunología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile. aferreira_uchile@yahoo.com.
authors.forename: Arturo
authors.initials: A
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D037282:Calreticulin / Q000235:genetics*; D002645:Chickens / Q000469:parasitology; D003001:Cloning, Molecular; D003172:Complement C1 / Q000276:immunology; D003165:Complement System Proteins / Q000276:immunology*; D015870:Gene Expression; D006790:Host-Parasite Interactions / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014224:Triatoma / Q000235:genetics*
chemical_list: D037282:Calreticulin; D003172:Complement C1; D003165:Complement System Proteins