Figure 5

Strain-dependent SAG2A polymorphisms in the C-terminal end alter protein conformation and regulatory features. (A) The consensus tree of SAG2A from the three clonal strains (I, II, III) of Toxoplasma gondii and the orthologue expressed in Neospora caninum. Alignment of the immunodominant epitope region shows that type II SAG2A displays a single additional glycine (position 142) within its IUP domain sequence. (B) Modeling of SAG2A from type I/III strains with the epitope region highlighted within the C-terminal end. The addition of glycine is responsible for significant changes in the SAG2A structure in type II strains, creating a predicted coil. (C) Bone marrow-derived macrophages (BMMs) and (D) Bone marrow-derived dendritic cells (BMDCs) were previously exposed to different parasite:cell ratios (multiplicity of infection – MOI) with RH and Me49 strain tachyzoites, in the presence of A4D12 monoclonal antibody or irrelevant IgG for 24 h. BMMs activation were promoted by LPS (10 ng/ml) + IFN-γ (100 ng/ml), 48 h prior to determination of nitrite levels. BMDC activation was promoted by LPS (1 μg/ml), 24 h prior to determination of IL-12p40 levels. Results are presented as mean ±SEM. Dashed lines indicate mean values for experimental controls following description. * Statistical significance (p < 0.05) related to antibody treatments.