EXPERIMENTAL TRYPANOSOMA-RANGELI INFECTION IN A MURINE MODEL

Trypanosoma rangeli experimental murine infections were performed in o rder to study parasitemias and anti-parasite antibody levels. Three gr oups of mice were used: a) mice infected with metatrypomastigotes deri ved from infected bugs; b) mice which received four reinoculations of metatrypomastigotes and c) mice immunosuppressed with cyclophosphamide . The results showed that bloodstream parasites can be found from the first day post inoculation reaching a peak at day 5 or 7 and then star t to decline. Parasites disappeared completely from the circulation af ter 20-25 days. However in the imunosuppressed group, parasites were f ound in blood up to 45 days post infection. The humoral immune respons e was monitored using an ELISA test and low levels of specific IgG and IgM immunoglobulins were found. However the IgG titers were lower tha n the IgM. One could conclude that IgM was the predominant immunoglobu lin isotype induced in a T. rangeli experimental infection because the highest titers were observed in the reinoculated group. IgM antibodie s also showed the most prominent crossreactivities with T. cruzi antig ens.