Acute Toxoplasma gondii infection modulates systemic immune response against allergen in a murine model of allergic airway inflammation

FENOY, I; CHIURAZZI, R; CASTERA, F;; MARTIN, V; GOLDMAN, A

Congreso; First French-Argentine Immunology Congress FAIC; 2010

Sociedad Argentina de Inmunología

We previously showed that acute infection with T.gondii blocks the development of allergic lung inflammation. OVA-sensitization during acute phase results in lower levels of OVA-specific IgE, IgG1 and Th2 cytokines from thoracic lymph nodes (LN). The increase in OVA-specific IgG2a and IFN-γ levels from OVA stimulated LN cells suggests that parasite infection induces a shift towards a Th1 response. Nevertheless, regulatory mechanisms could also be implicated since increases in TGF-β levels are detected. IL-10 behaves as a typical Th2 cytokine. The aim of the present study was to evaluate the systemic levels of Th1, Th2 and regulatory cytokines. Adult BALB/c mice were ip sensitized and aerosol challenged with OVA(O). One week before sensitization, the experimental group (OT) was orally infected with cysts from Beverly strain. Two days post challenge, splenocytes were in vitro stimulated with OVA or total lysate T.gondii antigen (TLA) and supernatant cytokine levels were evaluated. Sensitization during acute T.gondii infection induced a systemic decrease in OVA specific IL-4 (pg/ml: N:ND; T:ND; O:1341±198a; OT: 469±252) and IL-10 (pg/ml: N:ND; T: 28±28; O: 642±7 c; OT: 371±193c). An increase in allergen specific IFN-γ levels in OT compared to the O group was detected (pg/ml: N:ND; T:ND; O: 106±27a; OT: 322±4a). TGF-β levels showed no significant diferences. Nevertheless, a trend toward increased TGF-β production was observed in the OT group (OD: N: 0,02±0,09; T:0,06±0,02; O: 0,07±0,03; OT: 0,13±0,05). IFN-g and IL-10 levels in the infected groups stimulated with TLA are those expected for the immune response against T.gondii (IFNg pg/ml: N: 57±57; T: 850±67b; O: 13±4; OT: 694±235b; IL-10: N: 133±93; T: 720±265; O: 29±15; OT: 748±295). (Mean±SEM. a P<0,05 vs all groups; b P<0,05 vs N y O; c P<0,05 vs N y T. ND: not detected). These results show that systemic cytokine profile correlates with the one observed in lung draining LN