Scedosporium prolificans immunomes against human salivary immunoglobulin A

• Improvement of a workflow for protein extraction from Scedosporium prolificans.
• Immunomic study of proteins reacting with healthy human salivary Immunoglobulin A.
• Functional study of the antigens showed differences between conidia and hyphae.
• Conidial surface was stronger recognized by sIgA than hyphae.

The filamentous fungus Scedosporium prolificans is an emerging multidrug resistant pathogen related to serious infections mainly affecting immunocompromised individuals. Considering that it is frequently isolated from anthropic environments and penetrates mainly through the airways, the human mucosal immune system may play an important protective role against S. prolificans. To advance in the search for biomarkers and targets both for diagnosis and treatment, we analysed the S. prolificans immunomes recognized by human salivary Immunoglobulin A. Using indirect immunofluorescence, it was observed that conidia were strongly recognized, while hyphae were not. By 2-D immunoblotting and peptide mass fingerprinting, 25 immunodominant antigens in conidia and 30 in hyphae were identified. These included catalase, putative glyceronetransferase, translation elongation factor-1α, serine/threonine protein kinase, putative superoxide dismutase, putative mitochondrial cyclophilin 1 and peptidyl-prolyl cis-trans isomerase in conidiospores, and putative Hsp60, ATP synthase β chain, 40S ribosomal protein S0, citrate synthase and putative ATP synthase in hyphae. The functional study showed that metabolism – and protein fate – related enzymes were the most abundant antigens in conidia, whereas metabolism – , translation – , or energy production – related enzymes were in hyphae. The immunogenic proteins identified are proposed as candidates for the development of novel diagnostic tools or therapeutic strategies.

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