A DTU-dependent blood parasitism and a DTU-independent tissue parasitism during mixed infection of Trypanosoma cruzi in immunosuppressed mice

Abstract

Trypanosoma cruzi (Tc) diversity is determined by different biological, genetic, and biochemical markers and has been grouped into six discrete typing units (DTUs) or taxonomic groups (TcI-TcVI). This variability, coupled with natural reinfection or the hosts' immunosuppression, may play an important role in the pathogenesis of Chagas disease. Therefore, we evaluated the blood and tissue parasitism and genetic profile of mice coinfected with the TcII (JG) strain and TcI AQ1-7 (AQ) or MUTUM (MT) strains during the acute and chronic phases of the disease and during immunosuppression. T. cruzi blood populations in mixed infections were clearly associated with the TcII strain during acute and chronic phases or during immunosuppression. However, in tissues, the parasite populations were distributed according to the strain and the stage of infection. TcII populations overlapped TcI strains during the acute phase; in contrast, during chronic phase, both TcI strains were more prevalent than the TcII strain. The immunosuppression induced selective exacerbation of parasite populations, leading to reactivation of the TcII strain when associated with the AQ, but not with MT strain. Thus, a differential distribution of T. cruzi populations in blood and tissues with overlapping according to the stage of infection and strain used was observed. Blood parasitism was associated with the DTU TcII and tissue parasitism with a specific parasite strain and not with DTUs. Finally, to our knowledge, this is the first study to analyze subpatent blood parasitism and to simultaneously identify different T. cruzi populations in tissues and blood.

The TcI and TcII Trypanosoma cruzi experimental infections induce distinct immune responses and cardiac fibrosis in dogs

“…In the chronic phase, inflammation in the heart was balanced by tissue rearrangement and fibrosis, whereas Col infection at the chronic phase showed characteristics of inflammation. Sales-Campos et al (2014) noted that in mixed infection with TcI and TcII, parasitism in the acute phase was similar in composition to that of the inoculum, whereas in the chronic phase, TcI was prevalent.…”

Immunomodulation byTrypanosoma cruzi: Toward Understanding the Association of Dendritic Cells with Infecting TcI and TcII Populations

“…The four selected strains were as follows: AQ1.7, isolated from Triatoma sordida captured in the city of Agua Quente, BA; MUTUM, isolated from Panstrongylus megistus captured in the city of Uberaba, MG; 1849, isolated from an HIV+ patient presenting the cardiodigestive form of Chagas disease; and 2369, isolated from an HIV+ patient presenting the neurological form of Chagas disease. The AQ1.7 and MUTUM strains are classified as belonging to the DTU TcI [ 21 ], and strains 1849 and 2369 are classified as belonging to the DTU TcII (E. Lages-Silva, personal communication). The epimastigotes were thawed and placed in a culture of LLC-MK2 cell monolayers in LIT medium.…”

Trypanosoma cruzi strains cause different myocarditis patterns in infected mice

“…This observation is in sharp contrast with the data in humans, where patients infected with TcV strains have been shown to suffer cardiac pathology . More recently, some authors have associated mixed infection with different DTUs with severity of inflammation and tissular tropism (Sales-Campos et al, 2014;Silvina et al, 2014). For our study, we have selected strains with very different biological behavior both in vitro and in vivo.…”