RESUMO
Aspergillus flavus, a ubiquitous and saprophytic fungus, is the second most common cause of aspergillosis worldwide. Several mechanisms contribute to the establishment of the fungal infection. Extracellular vesicles (EVs) have been described as "virulence factor delivery bags" in several fungal species, demonstrating a crucial role during the infection. In this study, we evaluated production of A. flavus EVs and their immunomodulatory functions. We verified that A. flavus EVs induce macrophages to produce inflammatory mediators, such as nitric oxide, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-1ß. Furthermore, the A. flavus EVs enhance phagocytosis and killing by macrophages and induce M1 macrophage polarization in vitro In addition, a prior inoculation of A. flavus EVs in Galleria mellonella larvae resulted in a protective effect against the fungal infection. Our findings suggest that A. flavus EVs are biologically active and affect the interaction between A. flavus and host immune cells, priming the innate immune system to eliminate the fungal infection. Collectively, our results suggest that A. flavus EVs play a crucial role in aspergillosis.IMPORTANCE Immunocompromised patients are susceptible to several fungal infections. The genus Aspergillus can cause increased morbidity and mortality. Developing new therapies is essential to understand the fungal biology mechanisms. Fungal EVs carry important virulence factors, thus playing pivotal roles in fungal pathophysiology. No study to date has reported EV production by Aspergillus flavus, a fungus considered to be the second most common cause of aspergillosis and relevant food contaminator found worldwide. In this study, we produced A. flavus EVs and evaluated the in vitro immunomodulatory effects of EVs on bone marrow-derived macrophages (BMDMs) and in vivo effects in a Galleria mellonella model.
Assuntos
Aspergillus flavus/imunologia , Diferenciação Celular/imunologia , Vesículas Extracelulares/imunologia , Macrófagos/fisiologia , Animais , Aspergilose/imunologia , Aspergilose/prevenção & controle , Aspergillus flavus/patogenicidade , Polaridade Celular , Imunomodulação , Larva/microbiologia , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mariposas/microbiologiaRESUMO
A glycoprotein preparation containing 70% carbohydrates and 30% proteins was isolated from the mycelium of two strains of Aspergillus flavus and fractionated by ConA-Sepharose affinity chromatography. An immunodominant 35-kDa antigen was detected in a ConA-bound fraction (B fraction). It contained mannose and galactose in a 1.4:1.0 ratio. This antigen seems to be able to elicit an antibody response in patients with aspergillosis and in rabbits immunized with A. flavus whole cells. The carbohydrate units of the BF fraction appeared to be responsible for the antigenicity, since treatment with periodate removed most of the antibody binding capacity.
Assuntos
Anticorpos Antifúngicos/imunologia , Aspergilose/imunologia , Aspergillus flavus/imunologia , Glicoproteínas/imunologia , Epitopos Imunodominantes/imunologia , Animais , Anticorpos Antifúngicos/sangue , Glicoproteínas/química , Glicoproteínas/isolamento & purificação , Humanos , Immunoblotting , Epitopos Imunodominantes/química , Epitopos Imunodominantes/isolamento & purificação , Masculino , CoelhosRESUMO
Aspergillosis became an important opportunistic mycosis during the last years, with a great variety of clinical manifestations. To contribute to the replenishing of this mycosis serodiagnosis, biologic reactives (antigens and antisera) were prepared from strains of the species Aspergillus niger, Aspergillus flavus and Aspergillus terreus for their use in immunoprecipitation assays. The reactives were assessed by double immunospreading versus a reference commercial system; satisfactory results were obtained, and this guarantees the widening of the aspergillosis serodiagnosis in the Mycology Laboratory of the "Pedro Kourí" the Tropical Medicine Institute (IPK) with important imports savings.