Figure 1.

Macrophage depletion alters the host response to S. haematobium eggs in the bladder. A) Treatment protocol for mice undergoing egg injection and macrophage depletion. Mice received either control liposomes or LC given i.p. on d −1, bladder wall injection with control liposomes mixed with 1000 S. haematobium eggs, or LC mixed with 1000 eggs on d 0, followed by intravesical administration of control liposomes or LC on d 7 and 12. Mice were killed on d 14. B) Macrophage depletion of egg-injected bladders leads to sonographically apparent changes in granulomata. Mice underwent transabdominal microultrasonography on d 5 post-bladder wall injection (regimen shown in A). Granulomata are visible as highly echogenic masses within the ovoid bladder wall. Egg-injected bladders demonstrated smaller granulomata with hypoechoic peripheral zones after LC treatment. C) Macrophage depletion of egg-injected bladders leads to histologically apparent disruption in granuloma architecture. Typical histologic appearance of H&E staining of bladders 14 d postegg injection is shown. LC treatment of egg-injected bladders (regimen shown in A) leads to multiple paucicellular areas in granulomata and the lamina propria compared to controls. D) Macrophage depletion of egg-injected bladders leads to decreased granuloma infiltration by multiple nonmacrophage leukocyte subsets. Mice were killed on d 14 after egg injection and treatment with clodronate-loaded or control liposomes (regimen shown in A) and bladders harvested, homogenized into single cell suspensions, and subjected to flow cytometry specific for B cells, T cells, macrophages (Mϕ), AAMs, eosinophils (Eos), and neutrophils (Neu). Significance was assessed using a Student’s 2-tailed t test to compare both groups. Data shown are pooled from 3 experiments. *P < 0.05; **P < 0.01; ***P < 0.005.