Immunoproteomic study of Candida albicans hyphal secretome for the identification of diagnostic biomarker candidates of invasive candidiasis

ABSTRACT: Candida albicans is an opportunistic pathogen and a commensal fungus of the mucosa from many healthy patients. Invasive candidiasis (IC) has high levels of morbidity and mortality that are attributed to some extent to the difficulty in its early diagnosis. Diverse and immunogenic proteins with roles such as virulence and immune evasion are secreted by this pathogen. Immunoproteomics is an important technique for the assessment of antibody reactivities to immunogenic proteins and our group previously developed an algorithm to predict the clinical outcome in IC patients. With the ultimate purpose of discovering new biomarkers of IC, immunoproteomics was applied for the analysis of the serological response to hyphal C. albicans extracellular proteins. Gel-free proteomic analysis was performed by LC-MS/MS for the detection of the secreted proteins and 301 proteins were identified. As expected, gene ontology analysis in cellular component showed enrichment in proteins from extracellular region, cell wall, cell surface, cell periphery and intracellular region. Importantly, 46.5% of the intracellular proteins identified were also annotated in extracellular region. Furthermore, from the extracellular proteins identified here, 44 proteins were previously found to be immunogenic against human sera. To carry out immunoproteomic analysis, secreted proteins were separated by two-dimensional gel electrophoresis, electroblotted onto nitrocellulose membranes, and tested by Western blotting with three distinct pools of human sera: P1 (12 IC patients), P2 (11 patients with Candida infection associated with catheters) and P3 (11 patients without IC). A higher reactivity pattern was observed in P1 and P2 in comparison with P3. So far, Glx3 was immunogenic to P1 and P2 but not to P3. Eno1, Pgk1 and Pra1 were found to be more immunoreactive to both P1 and P2 than to the P3. This approach will contribute to a better and faster diagnosis of this life-threatening fungal infection.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Candida Albicans Sc5314

SUBMITTER: Concha Gil  

LAB HEAD: Concha Gil

PROVIDER: PXD013933 | Pride | 2021-07-05

REPOSITORIES: Pride