Mexican Trypanosoma cruziT. cruzi I Strains with Different Degrees of Virulence Induce Diverse Humoral and Cellular Immune Responses in a Murine Experimental Infection Model

Abstract EN

It is has been shown that the majority of T.

cruzi strains isolated from Mexico belong to the T.

cruzi I (TCI).

The immune response produced in response to Mexican T.

cruzi I strains has not been well characterized.

In this study, two Mexican T.

cruzi I strains were used to infect Balb/c mice.

The Queretaro (TBAR/MX/0000/Queretaro)(Qro) strain resulted in 100% mortality.

In contrast, no mortality was observed in mice infected with the Ninoa (MHOM/MX/1994/Ninoa) strain.

Both strains produced extended lymphocyte infiltrates in cardiac tissue.

Ninoa infection induced a diverse humoral response with a higher variety of immunoglobulin isotypes than were found in Qro-infected mice.

Also, a stronger inflammatory TH1 response, represented by IL-12p40, IFNγ, RANTES, MIG, MIP-1β, and MCP-1 production was observed in Qro-infected mice when compared with Ninoa-infected mice.

We propose that an exacerbated TH1 immune response is a likely cause of pathological damage observed in cardiac tissue and the primary cause of death in Qro-infected mice.