Kinetic of TLR2, TLR4 and cytokine gene expression during Trypanosoma cruzi acute infection in BALB/c and C57 BL/6 mice

EUGENIO ANTONIO CARRERA-SILVA; ROXANA CANO; NATALIA GUIÑAZÚ; MARÍA DEL PILAR AOKI; ANDREA PELLEGRINI; SUSANA GEA

Córdoba, Argentina

Congreso; VII Latin American Congress of Immunology; 2005

Asociación Latinoamericana de Inmunología

Toll like receptor (TLR) family is responsible for initiating acute immune response against pathogens by induction of proinflammatory cytokines. Our aim was to analyze the parasitemia-survival and the kinetic of TLR2, TLR4, TNFa, IL-6, IL-12, IL-10 and TGFb gene expression in splenocytes from infected BALB/c and C57BL/6. Mice (n=10 each) were ip infected with 5x103 trypomastigotes (Tulahuen). The histological study of heart, liver and spleen was also performed. Parasitemia was higher in BALB/c than in C57BL6 (4x106 versus 1x106parasites/ml at the peak), and mortality reached 40% and 85% respectively until 24 days post infection (dpi). TLR2 messenger showed an up-regulation at 24 dpi in C57BL/6 whereas TLR4-mRNA displayed a down-regulation in both strains compared to uninfected mice. IL-12, IL-6 and TNF mRNA showed the major changes, IL-12 increased in C57BL/6 and decreased in BALB/c. IL6 mRNA was up-regulated until 21 dpi, while TNFa messenger was up-regulated over the infection progress only in C57BL/6. On day 14, high levels of TNFa were also found in sera from C57BL/6 and BALB/c. In myocardium amastigote nests were observed earlier in BALB/c. Inflammatory infiltrates in heart and liver were found more frequently in C57BL/6. In acute T. cruzi infection, C57BL/6 showed a TLR2 mRNA up-regulation associated with an inflammatory cytokine profile and a higher number of cellular infiltrates.