title: The influence of ecto-nucleotidases on Leishmania amazonensis infection and immune response in C57B/6 mice.
abstract: Previous results from our laboratory and from the literature have implicated the expression of ecto-nucleotidases in the establishment of Leishmania infection. In the present study we evaluated the correlation between ecto-nucleotidasic activity and the infectivity of L. amazonensis promastigotes that were kept in culture for short or extended numbers of passages, a condition that is known to decrease parasite infectivity. We also analyzed the immune response associated with the infection by these parasites. As expected, we found that long-term cultured parasites induce the development of smaller lesions than the short-term cultured counterparts. Interestingly, long-term cultured parasites presented reduced ecto-nucleotidasic activity. In addition, cells recovered from animals infected with long-term cultured parasites produced higher amounts of IFN-gamma and have smaller parasite load, after 8weeks of infection. Furthermore, after 1week of infection, there is increased expression of the chemokine CCL2 mRNA in animals infected with short-term cultured parasites. Finally, infection of peritoneal macrophages by these parasites also shows marked differences. Thus, while short-term cultured parasites are able to infect a greater proportion of macrophages, cells infected by long-term cultured parasites express higher amounts of CXCL10 mRNA, which may activate these cells to kill the parasites. We suggest that the enzymes involved in metabolism of extracellular nucleotides may have an important role in infection by L. amazonensis, by acting directly in its adhesion to target cells and by modulating host cell chemokine production.
authors.affiliation: Departamento de Ciências Biológicas - ICEB/NUPEB, Universidade Federal de Ouro Preto, Morro do Cruzeiro, MG, Brazil.
authors.forename: Miriam Conceição
authors.initials: MC
authors.lastname: de Souza
authors.forename: Elisângela Aparecida
authors.initials: EA
authors.lastname: de Assis
authors.forename: Rodrigo Saar
authors.initials: RS
authors.lastname: Gomes
authors.forename: Eduardo de Almeida
authors.initials: Ede A
authors.lastname: Marques da Silva
authors.forename: Maria Norma
authors.initials: MN
authors.lastname: Melo
authors.forename: Juliana Lopes Rangel
authors.initials: JL
authors.lastname: Fietto
authors.forename: Luís Carlos Crocco
authors.initials: LC
authors.lastname: Afonso
mesh_terms: D000818:Animals; D018932:Chemokine CCL2 / Q000096:biosynthesis; D054357:Chemokine CXCL10 / Q000096:biosynthesis; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism; D007891:Leishmania / Q000201:enzymology / Q000276:immunology* / Q000472:pathogenicity*; D007896:Leishmaniasis / Q000469:parasitology / Q000473:pathology; D008264:Macrophages / Q000469:parasitology; D051379:Mice; D008810:Mice, Inbred C57BL; D009708:Nucleotidases / Q000096:biosynthesis*; D015800:Protozoan Proteins / Q000096:biosynthesis*; D012692:Serial Passage; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D018932:Chemokine CCL2; D054357:Chemokine CXCL10; D015800:Protozoan Proteins; D037521:Virulence Factors; D007371:Interferon-gamma; D009708:Nucleotidases