DEVELOPMENT AND VAL I D ATION OF A GLYCOCONJUGATE MAGNETICS BEADS-BASEDASSAY FOR HUMAN BRUCELLOSIS

CIOCCHINI AE; REY SERANTES DA; MELLI LJ; DEODATO B; WALLACH J; FELDMAN MF; UGALDE JE; COMERCI DJ

Mendoza

Congreso; XLVIII Reunión Anual SAIB; 2012

Argentine Society for Biochemistry and Molecular Biology Research

The O-polysaccharide (OPS) of Brucella spp. is a homopolymer of N-formylperosamine identical to the OPS from Yersinia enterocolitica O:9. We took advantage of this similarity to explore the application of a recombinant Y. enterocolitica O:9 OPS-protein conjugate (OPS-AcrA) as a novel antigen for diagnosis of human brucellosis. In this work, we have developed, optimized and validated an indirect immunoassay using OPS-AcrA coupled to magnetic beads. OPS-AcrA was produced in Y. enterocolitica O:9 cells co-expressing the OTase PglB of Campylobacter jejuni and the protein acceptor AcrA. Introduction of PglB in Y. enterocolitica resulted in the transfer of the OPS from its lipid carrier to AcrA. The assay was validated using a panel of characterized serum samples obtained from healthy individuals and patients of different clinical groups. To determine the cutoff values a receiver-operating characteristic analysis was performed. The cutoff value that concurrently optimizes sensitivity and specificity was 13.20% which resulted in a diagnostic sensitivity and specificity of 100% and 98.81%, respectively; a cutoff value of 16.15% resulted in a test sensitivity of 93.48% and a test specificity of 100%. Due to the low cost in terms of production of the antigen, reduced incubation time, and simplicity we propose the glycoconjugate-beads assay as a Point-Of-Care test for diagnosis of brucellosis.