IMMUNE RESPONSE DYNAMICS OF Experimentally Infected Dogs with Trypanosoma cruzi “Y” strain

Abstract

The aim of this study was to evaluate the dynamics of humoral immune response of two dogs experimentally infected with Trypanosoma cruzi "Y" strain, in order to identify the seroconvertion and the antibody titles variation. Animal’s blood samples were collected weekly, during 56 weeks and indirect immunofluorescence test (IIF) was carried out for anti-T.cruzi antibodies detection. On the first week after inoculation antibodies were not detected in any animals. One dog produced antibodies with gradual titers increase after the second week, achieving a maximum titer of 1,280 after four weeks of inoculation. Titers declined between the fourth and fifth weeks, ranging from 80 to 320 up to the 56^th week. In the other dog, antibodies output peak was verified between the 11^th and 13^th weeks and then titers started to decrease. Soon after, a new peak was observed between the 22^nd and 23^rd weeks, with a maximum titer of 640. From the 25^th week on, it was verified a stabilization tendency, with titers ranging from 80 to 320. In the last week, titer was kept in 80 in both dogs. This study shows that dogs experimentally inoculated with T. cruzi "Y" strain develops a quick immune response, and produce high antibodies titles. Considering the ethical limits of an experimental design, these animals can be used as experimental models in studies of the natural history and immunopathology of Chagas disease, and also for antiserum production.