title: Phylogeny and immune evasion: a putative correlation for cerebral Pseudallescheria/Scedosporium infections.
abstract: Representatives of the genus Pseudallescheria (anamorph: Scedosporium) are saprobes and the aetiologic agent of invasive mycosis in humans. After dissemination, the central nervous system (CNS) is one of the most affected organs. Prerequisites for the survival of Pseudallescheria/Scedosporium in the host are the ability to acquire nutrients and to evade the immune attack. The cleavage of complement compounds via the secretion of fungal proteases might meet both challenges since proteolytic degradation of proteins can provide nutrients and destroy the complement factors, a fast and effective immune weapon in the CNS. Therefore, we studied the capacity of different Pseudallescheria/Scedosporium species to degrade key elements of the complement cascade in the cerebrospinal fluid and investigated a correlation with the phylogenetic background. The majority of the Pseudallescheria apiosperma isolates tested were demonstrated to efficiently eliminate proteins like complement factors C3 and C1q, thus affecting two main components of a functional complement cascade, presumably by proteolytic degradation, and using them as nutrient source. In contrast, the tested strains of Pseudallescheria boydii have no or only weak capacity to eliminate these complement proteins. We hypothesise that the ability of Pseudallescheria/Scedosporium strains to acquire nutrients and to undermine the complement attack is at least partly phylogenetically determined.
authors: Institute of Microbiology, Leopold-Franzens-University Innsbruck, Innsbruck, Austria.
authors: Johannes
authors: J
authors: Rainer
authors: Günter
authors: G
authors: Rambach
authors: Josef
authors: J
authors: Kaltseis
authors: Magdalena
authors: M
authors: Hagleitner
authors: Silvia
authors: S
authors: Heiss
authors: Cornelia
authors: C
authors: Speth
mesh_terms: D001927:Brain Diseases / Q000276:immunology / Q000382:microbiology; D020314:Central Nervous System Fungal Infections / Q000276:immunology / Q000382:microbiology; D015922:Complement C1q / Q000134:cerebrospinal fluid / Q000276:immunology; D003176:Complement C3 / Q000134:cerebrospinal fluid / Q000276:immunology; D003165:Complement System Proteins / Q000134:cerebrospinal fluid*; D006801:Humans; D057131:Immune Evasion; D009181:Mycoses / Q000134:cerebrospinal fluid / Q000276:immunology / Q000382:microbiology; D010802:Phylogeny; D011541:Pseudallescheria / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D021681:Scedosporium / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*
chemical_list: D003176:Complement C3; D015922:Complement C1q; D003165:Complement System Proteins