Comprehensively assess the humoral immune response to Coccidioides infection using a new high-resolution, proteome-wide antibody profiling assay in patients with and without coccidioidal meningitis.

Known protein and predicted protein coding regions of the C. immitis and C. posadasii genomes were computationally tiled into overlapping 50 amino acid segments and collapsed on 95% sequence similarity. Oligonucleotides were synthesized, cloned, and packaged into T7 bacteriophage so the encoded peptides would be displayed on the phage surface. Multiple rounds of immunoprecipitation with patient-matched cerebrospinal fluid (CSF) and serum were performed (n=20 patients), and immunoprecipitated phage were sequenced. Peptides were counted by aligning sequences to the synthetic Coccidioides peptide library. Peptide enrichment was calculated relative to uninfected and no template controls.

To assess the quality of the new Coccidioides phage display library, the library was sequenced. On average, 94% of the 202,919 designed Coccidioides peptides were displayed. Preliminary immunoprecipitations with coccidioidal meningitis CSF enriched multiple proteins, including two known extracellular antigens: SOWgp and a CFEM domain containing extracellular membrane protein.