Figure I.

(a) Dendritic cell (DC) grazing on the surface of an attenuated schistosomulum (S) in a skin-draining lymph node primes the immune system for a Th1 response. (The tissue was not post-fixed in uranyl acetate to stabilise the membranocalyx.) Scale bar = 1 µm. (b) Intimate contact between the schistosomulum tegument (T) and pulmonary capillary endothelium (EN) may facilitate transfer of surface proteins to the interstitial spaces as vesicles (V) mediating transcytosis are evident at the luminal surface. Bar = 0.25 µm. (c) Challenge schistosomulum (S) in the lungs of a vaccinated mouse surrounded by an inflammatory focus largely composed of lymphocytes and monocytes. A pleural infiltrate (P) is also evident on the lung surface. The focus impedes migration and deflects some larvae into the alveoli, rather than killing them by cytolytic mechanisms. Scale bar = 50 µm.