The ESX-1 Substrate PPE68 Has a Key Function in ESX-1-Mediated Secretion in Mycobacterium marinum.

Mycobacteria use specialized type VII secretion systems (T7SSs) to secrete proteins across their diderm cell envelope. One of the T7SS subtypes, named ESX-1, is a major virulence determinant in pathogenic species such as Mycobacterium tuberculosis and the fish pathogen Mycobacterium marinum. ESX-1 secretes a variety of substrates, called Esx, PE, PPE, and Esp proteins, at least some of which are folded heterodimers.

EphA2-Dependent Internalization of Conidia in A549 Lung Cells Is Modulated by DHN-Melanin.

Dectin-1 and ephrin type-A receptor 2 (EphA2) receptors recognize β-glucan present in the fungal cell wall. Inhibition of Dectin-1 with the monoclonal 2a11 antibody was shown to reduce internalization of conidia of the human pathogen into epithelial cells. In this study, we investigated the role of the EphA2 receptor present on A549 epithelial type II lung cells in the interaction with conidia.

Expression profile analysis reveals that Aspergillus fumigatus but not Aspergillus niger makes type II epithelial lung cells less immunological alert.

Background: Aspergillus fumigatus is the main causative agent of aspergillosis. Infections rarely occur in immunocompetent individuals, indicating efficient clearance of conidia by pulmonary defense mechanisms. Other aspergilli like Aspergillus niger also cause infections but to a much lesser extent.