Design and application of GB virus C (GBV-C) peptide microarrays for diagnosis of GBV-C/HIV-1 co-infection

The main objectives of the design of GB virus C (GBV-C) peptide microarrays are the miniaturisation of antigen–antibody interaction assays, the simultaneous analysis of several peptide sequences and the reduction in the volume of serum required from patients since this always represents a limiting factor in studies to develop new systems for diagnosing human diseases. We herein report the design of a microarray immunoassay based on synthetic peptides derived from the GBV-C E2 protein to evaluate their diagnostic value in detecting anti-E2 antibodies in HIV-1 patients. To this end, peptide microarrays were initially prepared to identify the most relevant epitopes in the GBV-C E2 protein. Thus, 124 peptides composed of 18 amino acids covering the whole E2-protein sequence, with 15 residue overlaps, were spotted in triplicate onto γ-aminopropyl silane-functionalised adsorbent binding slides. The procedure to select the E2 protein epitopes was carried out using serum samples from HIV-1-infected patients. The samples had previously been tested for the presence or absence of GBV-C anti-E2 antibodies by means of the Abbott test. Thus, 11 specific epitopes in the GBV-C E2 protein were identified. Subsequently, peptide antigen microarrays were constructed using the E2 epitopes identified to detect GBV-C anti-E2 antibodies in the serum of HIV-1-infected patients with no known GBV-C co-infection. The 11 peptides selected identified anti-E2 GBV-C antibodies among HIV-1-infected patients, and a reactivity of 47 % was established. The potential antigenic peptides selected could be considered a useful tool for designing a new diagnostic system based on peptide microarrays to determine anti-GBV-C E2 antibodies in the serum of HIV-1-infected patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-012-6585-3) contains supplementary material, which is available to authorized users.