Immunization of Mice with aTrypanosoma cruzi-Like Strain Isolated from a Bat: Predictive Factors for Involvement of Eosinophiles in Tissue Damage

Abstract

The granules of eosinophiles are cytotoxic to Trypanosoma cruzi trypomastigote and amastigote forms and to several cell types of the host, revealing their role in either parasite elimination or the production of tissue lesions. In this study, we evaluated the biological characteristics of T. cruzi infection that are responsible for the increase in tissue eosinophile levels in mice previously immunized with a bat isolated T. cruzi-like strain that does not infect mice. Nonisogeneic mice were divided into 24 groups that received from zero to three inoculations of T. cruzi-like RM1 strain, with or without adjuvant, followed by challenge with T. cruzi VIC or JG strains. Uni- and multivariate comparisons were performed comparing the tissue eosinophile levels with the parasitemia peak, severity of myositis in skeletal muscle, phase of infection, and the immunization strategies induced by the T. cruzi-like strain (adjuvant, number of reinoculations, and parasites). Although the severity of inflammation was higher in the acute phase, the score of tissue eosinophiles was similar in the acute and chronic phases of infection. In addition, there was a positive correlation among eosinophile levels and parasitemia peak. In the chronic phase, a greater eosinophile count was accompanied by an augmentation of myositis. Regardless of the phase of infection, we observed a positive correlation between the intensity of eosinophile infiltration and the number of sensitizations with T. cruzi-like strain. The multivariate analysis showed that the peak of parasitemia, number of inoculations with the T. cruzi-like strain, and severity of myositis were associated with greater tissue eosinophilia, in comparison with adjuvant, T. cruzi strains used in the challenge or tissue parasitism. Therefore, tissue eosinophile levels proved to be an important parameter in the pathogenesis of experimental Chagas disease in the acute and chronic phases of infection and might be related to reinfections, parasite multiplication ability, and severity of inflammatory process.

Different Infective Forms Trigger Distinct Immune Response in Experimental Chagas Disease

“…Despite the importance of eosinophils have been demonstrated in 80 years, there have been few recent studies involving the participation of these cells in Chagas disease. Nascentes et al (2010) [24] to assess the participation of eosinophils in tissue damage in mice infected by VIC and JG strains of T. cruzi , also observed a higher number of eosinophils coincided with parasitemia peak in both strains used. Moreover, the number of eosinophils in the heart tissue was lower than in the skeletal muscle tissue.…”

Multiparametric and semiquantitative scoring systems for the evaluation of mouse model histopathology - a systematic review

“…One recently published scoring system evaluated the extent of Trypanosoma -induced myositis [104] while the other scoring system was developed to quantify the extent of ischemia-induced muscle necrosis by the parameters necrosis, infiltration and hemorrhage [105]. …”

Biomarkers and Their Possible Functions in the Intestinal Microenvironment of Chagasic Megacolon: An Overview of the (Neuro)inflammatory Process

“…The presence of eosinophils in the in vitro and/or in vivo CD study models in humans was associated with protozoan destruction and control, tissue damage, and inflammatory process maintenance in both the acute and chronic phases of the disease [162][163][164][165][166][167][168]. In addition, this cell type was correlated with intestinal fibrosis in the nerve plexus and muscle layers of patients with megacolon, regions that showed an increased level of eosinophils compared to that in noninfected people and infected patients without megacolon [13].…”