Immunoproteomic Identification of <i>Scedosporium boydii</i> Antigens with Potential Diagnostic Interest in Cystic Fibrosis Patients

Fungal infections caused by <i>Scedosporium</i>/<i>Lomentospora</i> species are a significant threat to patients with cystic fibrosis (pwCF), ranking as the second most common filamentous fungi in their airways after <i>Aspergillus</i>. Current serodiagnostic methods, such as counterimmunoelectrophoresis and ELISA using crude extracts, lack standardization and commercial availability and often show cross-reactivity with other fungi. This study aimed to identify specific <i>Scedosporium boydii</i> antigens with potential for serodiagnosis in pwCF. An immunoproteomic approach combining two-dimensional polyacrylamide gel electrophoresis, Western blot, and mass spectrometry was used to analyze the antigenic profile of <i>S. boydii</i> against sera from pwCF with positive cultures for <i>Scedosporium</i>/<i>Lomentospora</i> (Scedo+) and mice intravenously infected with these fungi. We identified 22 proteins specifically recognized by sera from pwCF Scedo+ and mice infected with <i>S. boydii</i>, but not by sera from pwCF or mice infected with <i>Aspergillus</i> spp. or uninfected controls. These proteins are primarily involved in metabolism and exhibit catalytic activity. The most prevalent antigens were the heat shock protein 70, 6-phosphogluconate dehydrogenase, 3-ketoacyl-CoA thiolase, and phosphoenolpyruvate carboxykinase, recognized by 67-81% of pwCF Scedo + sera with minimal cross-reactivity to negative samples. This work identifies promising candidates for the specific serodiagnosis of <i>Scedosporium</i>/<i>Lomentospora</i> infections in pwCF. Data are available via ProteomeXchange (PXD053392).