Chagas disease is a severe inflammatory syndrome caused by infection with a protozoan parasite, Trypanosoma cruzi. Although transmission occurs mostly through an intermediate insect host, the infection is silent and chronic carriers pose a significant risk through the transfer of infected products made from donated blood of these individuals to blood recipients. Up to 500,000 new cases and 66,000 deaths are reported annually in countries in South and Central America where the parasite lives. The combination of immigration and expansion of the range where the parasite host lives is, however, leading to large numbers of infected individuals in countries that until recently did not have Chagas disease. The United States is foremost amongst these. Control and prevention of Chagas disease relies on the accurate detection of infection. Improvements in the currently available diagnostics are required. In our research we have found a novel way to identify pieces of the parasite (certain proteins) that could be used as components of a new diagnostic test. Since they have the ability to tightly bind antibodies from infected individuals and are often selected from a variety of individual diagnostic leads, we stitch them together as ?multiple antibody-binding epitopes? to enhance the diagnostic power. These ?polyproteins? maximize the ability to react with infected serum, enabling the new test. We have used computational searches to identify a number of novel diagnostic candidates in T. cruzi and our preliminary data indicate several that hold promise as important components with a new diagnostic test. The research in this proposal will develop an improved and cost- effective diagnostic test to permit screening for T. cruzi infection / Chagas disease. The proposed research will proceed in two steps: In step 1 we will optimize and tightly define the production parameters of two lead polyproteins. In step 2 we will integrate these diagnostic leads into a format consistent with use in standard reference laboratories/ blood centers as well distribute them to our extensive network of collaborators in a wide variety of T. cruzi-endemic regions for further evaluation. If successful, in the phase II application, prototype tests and adjunct test formats will be produced and extensively evaluated as potential commercial tests.
A cost-effective test with enhanced specificity and sensitivity that could readily be integrated into reference laboratories for the detection of T. cruzi infection in mass screening programs would greatly aid in the fight against this deadly disease and help protect donated blood and organ supply. By optimizing the manufacture of candidate fusion proteins, establishing technical parameters within a test format and evaluating against samples from multiple T. cruzi-endemic regions this phase I proposal will allow progress toward a commercial test leading to an improvement in global health.
