title: Interaction of an opportunistic fungus Purpureocillium lilacinum with human macrophages and dendritic cells.
abstract: BACKGROUND
  Purpureocillium lilacinum is emerging as a causal agent of hyalohyphomycosis that is refractory to antifungal drugs; however, the pathogenic mechanisms underlying P. lilacinum infection are not understood. In this study, we investigated the interaction of P. lilacinum conidia with human macrophages and dendritic cells in vitro.
  
  
  METHODS
  Spores of a P. lilacinum clinical isolate were obtained by chill-heat shock. Mononuclear cells were isolated from eight healthy individuals. Monocytes were separated by cold aggregation and differentiated into macrophages by incubation for 7 to 10 days at 37°C or into dendritic cells by the addition of the cytokines human granulocyte-macrophage colony stimulating factor and interleukin-4. Conidial suspension was added to the human cells at 1:1, 2:1, and 5:1 (conidia:cells) ratios for 1h, 6h, and 24h, and the infection was evaluated by Giemsa staining and light microscopy.
  
  
  RESULTS
  After 1h interaction, P. lilacinum conidia were internalized by human cells and after 6h contact, some conidia became inflated. After 24h interaction, the conidia produced germ tubes and hyphae, leading to the disruption of macrophage and dendritic cell membranes. The infection rate analyzed after 6h incubation of P. lilacinum conidia with cells at 2:1 and 1:1 ratios was 76.5% and 25.5%, respectively, for macrophages and 54.3% and 19.5%, respectively, for cultured dendritic cells.
  
  
  CONCLUSIONS
  P. lilacinum conidia are capable of infecting and destroying both macrophages and dendritic cells, clearly demonstrating the ability of this pathogenic fungus to invade human phagocytic cells.
authors.affiliation: Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
authors.forename: Mariana Lima Perazzini
authors.initials: ML
authors.lastname: Peixoto
authors.affiliation: Laboratório de Biopatógenos e Ativação Celular, Universidade Federal Fluminense, Niterói, RJ.
authors.forename: Dilvani Oliveira
authors.initials: DO
authors.lastname: Santos
authors.affiliation: Laboratório de Biopatógenos e Ativação Celular, Universidade Federal Fluminense, Niterói, RJ.
authors.forename: Ivy de Castro Campos de
authors.initials: Ide C
authors.lastname: Souza
authors.affiliation: Laboratório de Biopatógenos e Ativação Celular, Universidade Federal Fluminense, Niterói, RJ.
authors.forename: Eloah Christina Lyrio
authors.initials: EC
authors.lastname: Neri
authors.affiliation: Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
authors.forename: Danielly Correa Moreira de
authors.initials: DC
authors.lastname: Sequeira
authors.affiliation: Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
authors.forename: Paula Mello
authors.initials: PM
authors.lastname: De Luca
authors.affiliation: Laboratório de Taxonomia, Bioquímica e Bioprospecção de Fungos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil.
authors.forename: Cíntia de Moraes
authors.initials: Cde M
authors.lastname: Borba
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000502:physiology*; D003713:Dendritic Cells / Q000382:microbiology*; D006801:Humans; D008264:Macrophages / Q000382:microbiology*; D010587:Phagocytosis; D013997:Time Factors