Immunization with recombinant Trypanosoma cruzi ribosomal P2beta protein induces changes in the electrocardiogram of immunized mice.

Abstract

Molecular expression cloning techniques revealed that patients with severe chronic Chagas heart disease showed a strong humoral response against the cloned C-terminal portion of the Trypanosoma cruzi ribosomal P2beta protein, previously named JL5. The main linear epitope of this polypeptide was mapped to the 13 C-terminal amino acid sequence EEEDDDMGFGLFD (named R13), which is almost identical to the mammalian ribosomal P consensus sequence EESDDDMGFGLFD (named H13). Enzyme-linked immunosorbent assay measurements demonstrated that sera from patients with chronic Chagas heart disease presented a very specific anti-P humoral response with high anti-R13, but low H13 antibody levels. We attempted to develop an animal model that would reproduce, at least partially, two features of the human infection: (1) the serological pattern of the anti-P response, and (2) specific cardiac symptoms. To this effect, mice were immunized with T. cruzi P2beta recombinant protein. Immunization reproduced the typical anti-P antibody profile defined for chronic infections, but did not induce cardiac inflammatory lesions. However, it altered significantly the electrocardiograms of immunized mice. It is suggested that this assay represents a functional test for assessing the biological activity of antibodies against T. cruzi ribosomal P protein on cardiac muscle.