Peptide based diagnostics: Are random-sequence peptides more useful than tiling proteome sequences?

Krupa Arun Navalkar, Stephen Johnston, Phillip Stafford

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Diagnostics using peptide ligands have been available for decades. However, their adoption in diagnostics has been limited, not because of poor sensitivity but in many cases due to diminished specificity. Numerous reports suggest that protein-based rather than peptide-based disease detection is more specific. We examined two different approaches to peptide-based diagnostics using Coccidioides (aka Valley Fever) as the disease model. Although the pathogen was discovered more than a century ago, a highly sensitive diagnostic remains unavailable. We present a case study where two different approaches to diagnosing Valley Fever were used: first, overlapping Valley Fever epitopes representing immunodominant Coccidioides antigens were tiled using a microarray format of presynthesized peptides. Second, a set of random sequence peptides identified using a 10,000 peptide immunosignaturing microarray was compared for sensitivity and specificity. The scientific hypothesis tested was that actual epitope peptides from Coccidioides would provide sufficient sensitivity and specificity as a diagnostic. Results demonstrated that random sequence peptides exhibited higher accuracy when classifying different stages of Valley Fever infection vs. epitope peptides. The epitope peptide array did provide better performance than the existing immunodiffusion array, but when directly compared to the random sequence peptides, reported lower overall accuracy. This study suggests that there are competing aspects of antibody recognition that involve conservation of pathogen sequence and aspects of mimotope recognition and amino acid substitutions. These factors may prove critical when developing the next generation of high-performance immunodiagnostics.

Original languageEnglish (US)
Pages (from-to)10-21
Number of pages12
JournalJournal of Immunological Methods
Volume417
DOIs
StatePublished - Feb 1 2015

Keywords

  • Immunoassay
  • Immunodiagnostic
  • Immunosignature
  • Valley Fever

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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