Comparison of Recombinant Trypanosoma cruzi Peptide Mixtures versus Multiepitope Chimeric Proteins as Sensitizing Antigens for Immunodiagnosis

CAMUSSONE CECILIA; GONZALEA VERÓNICA; BELLUZO M SOLEDAD; PUJATO NAZARENA; RIBONE MARÍA; LAGIER CLAUDIA; MARCIPAR IVÁN

Clinical and Vaccine Immunology

American Society for Microbiology

Año: 2009 vol. 19 p. 899 - 905

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} p.MsoBodyText, li.MsoBodyText, div.MsoBodyText {margin:0cm; margin-bottom:.0001pt; text-align:justify; line-height:150%; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The aim of this work was to determine the best strategy to display antigens (Ags) on immunochemical devices, to improve the test selectivity and sensitivity. We evaluated comparatively 5 Trypanosoma cruzi antigenic recombinant peptides, chose the 3 more sensitive, built up chimeras bearing these selected Ags, and systematically compared by enzyme-linked immunosorbent assay the performance of the assortments of those peptides with that of the multiepitope constructions bearing all those peptides lineally fused. The better-performing Ags compared included peptides homologous to the previously described T. cruzi flagelar repetitive antigen (here named RP1), the shed acute-phase antigen (RP2), B13 (RP5), and the chimeric recombinant proteins CP1 and CP2, bearing repetitions of RP1-RP2 and RP1-RP2-RP5, respectively. The diagnostic performance of these Ags was assessed by the discrimination efficiency  (mean optical density value of the positive serum samples tested over the cutoff value), compared with each other either alone, in mixtures or as peptide-fused chimeras, and with that of total parasite homogenate (TPH). The  obtained for CP1 and CP2 were 25% and 52% higher than those of their individual-Ags mixtures, respectively. CP2 was the only antigen that showed enhanced discrimination efficiency between Chagas’ positive- and negative samples, when compared with TPH. This study highlights the convenience of performing immunochemical assays using hybrid, single-molecule, chimeric Ags instead of peptide mixtures. CP2 preliminary tests rendered 98.6% sensitivity when evaluated with a 141-Chagas’ positive serum panel, and 99.4% specificity, as assessed with a 164-Chagas’ negative serum panel containing 15 samples from individuals infected with Leishmania ssp.