title: Cryptococcus neoformans induces antimicrobial responses and behaves as a facultative intracellular pathogen in the non mammalian model Galleria mellonella.
abstract: Cryptococcus neoformans is an encapsulated opportunistic fungal pathogen that is found in multiple niches in the environment and that can cause fatal meningoencephalitis in susceptible patients, mainly HIV+ individuals. Cryptococcus also infects environmental hosts such as nematodes, insects and plants. In particular, C. neoformans can kill the lepidopteran Galleria mellonella, which offers a useful tool to study microbial virulence and drug efficacy. Galleria mellonella immunity relies on innate responses based on melanization, accumulation of antimicrobial peptides, and cellular responses as phagocytosis or multicellular encapsulation. In this work we have investigated the immune response of G. mellonella during cryptococcal infection. We found that G. mellonella infected with C. neoformans had a high lytic activity in their hemolymph. This response was temperature- and capsule-dependent. During interaction with phagocytic cells, C. neoformans behaved as an intracellular pathogen since it could replicate within hemocytes. Non-lytic events were also observed. In contrast to Candida species, C. neoformans did not induce melanization of G. mellonella after infection. Finally, passage of C. neoformans through G. mellonella resulted in changes in capsule structure as it has been also reported during infection in mammals. Our results highlight that G. mellonella is an optimal model to investigate innate immune responses against C. neoformans.
authors.affiliation: a Mycology Reference Laboratory ; National Center for Microbiology ; Instituto de Salud Carlos III ; Carretera Majadahonda-Pozuelo, Km2 ; Majadahonda , 28220 , Madrid , Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Trevijano-Contador
authors.forename: Inés
authors.initials: I
authors.lastname: Herrero-Fernández
authors.forename: Irene
authors.initials: I
authors.lastname: García-Barbazán
authors.forename: Liliana
authors.initials: L
authors.lastname: Scorzoni
authors.forename: Cristina
authors.initials: C
authors.lastname: Rueda
authors.forename: Suélen Andreia
authors.initials: SA
authors.lastname: Rossi
authors.forename: Rocío
authors.initials: R
authors.lastname: García-Rodas
authors.forename: Oscar
authors.initials: O
authors.lastname: Zaragoza
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism; D003453:Cryptococcosis / Q000276:immunology / Q000382:microbiology; D003455:Cryptococcus neoformans / Q000276:immunology / Q000472:pathogenicity*; D004195:Disease Models, Animal; D006434:Hemocytes / Q000382:microbiology; D006458:Hemolymph / Q000276:immunology* / Q000382:microbiology; D007113:Immunity, Innate / Q000276:immunology; D009036:Moths / Q000276:immunology* / Q000382:microbiology*
chemical_list: D023181:Antimicrobial Cationic Peptides
keywords: Cryptococcus neoformans; Galleria mellonella; antimicrobial peptides; hemocytes; intracellular pathogenesis; melanin