Antibody maturation in Trypanosoma cruzi-infected rats

The study of antibody avidity changes during infection has improved the und erstanding of the pathologic processes involved in several infectious disea ses. In some infections, like toxoplasmosis, this information is being used for diagnostic purposes. Results of the evolution of antibody avidity for different specific antigens in Trypanosome cruzi-infected rats are presente d. A Western blotting technique, combined with avidity analysis to identify antigens that elicit high-avidity antibodies, is suggested. In this system , antibodies showed high avidity values only during the chronic phase of in fection and only in relation to antibodies against 21-, 33-, 41-, 42-, 56-, 58-, 66-, and 72-kDa antigens, Finally, a 97-kDa T. cruzi antigen, which w as recognized by high-avidity antibodies and occurred in noninfected rats, was identified. These results allow us to evaluate the different antigens i n chagasic infection. Our results show that with the correct choice of anti gen it is possible to detect differences in maturation of antibodies and to discriminate, in an experimental model, between recent (acute) and chronic infections.