Figure 1.
Bladder wall injection of S. haematobium eggs results in synchronous granuloma formation.
Intramural injection of S. haematobium eggs results in rapid and localized injection site response followed by progressive expansion and consolidation over several weeks (serial micro-ultrasonography of a single representative animal, A–D; histology, E–H). Lymphoid follicles in H are marked with arrowheads. Scale bars for panels E, I, J, and L (lower right hand corner for each) are 100 microns long. Immunohistochemical characterization demonstrates central macrophage granuloma formation around injected eggs (arrows) with peripheral accumulation of other inflammatory cells (I–K, anti-CD68 brown). Epithelioid cells (activated macrophages) are indicated with arrowheads. Egg injection also induces early and sustained urothelial hyperplasia with reactive nuclear changes (L–O).
Figure 2.
S. haematobium egg-injected bladders develop fibrosis and urinary dysfunction.
Egg-injected bladders demonstrate histologically-apparent fibrosis within granulomata beginning at post-injection day 7 (A, Masson's trichrome stain, collagen stains blue). Later time points demonstrate increased collagen staining area and intensity (B). Total bladder soluble collagen content correlates with histologic evaluation (C). Egg-injected mice demonstrate increased urinary frequency (1 week post injection, D).
Figure 3.
S. haematobium egg-injected bladders demonstrate a local Type 2 immune response.
Egg-injected bladders feature elevated levels of the Type 2-associated cytokines IL-4, IL-13, and eotaxin (A) without significant changes in TH1- or TH17-associated cytokines (e.g. IFN-γ [B] and IL-17 [C], respectively). Cytokines and chemokines associated with innate immune activation (e.g. KC, TNF-α, MIP-1α, MCP-3, [D]) are persistently elevated relative to control. The immunosuppressive cytokines IL-10 and TGF-β were not clearly differentially regulated in egg- versus control-injected mice (E).
Figure 4.
S. haematobium egg-injected bladders accumulate a mixed inflammatory infiltrate dominated by eosinophils and neutrophils.
Congruent with histologic evaluation, serial flow cytometric analyses of single cell suspensions made from egg-injected bladders demonstrate progressive accumulation of (A) eosinophils (SiglecF+CCR3+), (B) neutrophils (CD11b+Gr-1+), (C) B cells (B220+), and—to a lesser extent— (D) T cells (CD3+).
Figure 5.
S. haematobium egg-injected mice demonstrate Type 2 immune responses in draining lymph nodes.
Pelvic lymph nodes from egg-injected mice demonstrate persistently elevated expression of Type 2-associated cytokines (e.g. IL-4) without corresponding increases in the TH1-associated cytokines IFN-γ and IL-12. The TReg-associated marker FoxP3 is suppressed late in the experimental time course, while the immunosuppressive cytokines IL-10 and TGF-β remain unchanged. IL-17 was not detected (N.D.).
Figure 6.
S. haematobium egg-injected mice display systemic Type 2 cytokine and immunoglobulin responses.
Egg-injected mice demonstrate elevated serum levels of Type 2-associated cytokines (e.g. IL-5) with decreased or unchanged serum levels of TH1- and TH17-associated cytokines (e.g. IFN-γ and IL-17, respectively, [A]). The Type 2 bias in systemic cytokine expression parallels increased IgE production (B).
Table 1.
Assayed proteins.