Abstract
Infectious cercariae of Schistosoma mansoni gain entry to the mammalian host through the skin where they induce a transient inflammatory influx of mononuclear cells. Some of these cells have antigen-presenting cell function (MHCII+) and have been reported to migrate to the skin-draining lymph nodes (sdLN) where they have the potential to prime CD4+ cells of the acquired immune response. Here, in mice exposed to vaccinating radiation-attenuated schistosome larvae, which induce high levels of protective immunity to challenge infection, we describe the parasite-induced migration of Langerhans cells (LCs) from the epidermal site of immunisation to the sdLN using a specific monoclonal antibody that recognises langerin (CD207). CD207+ cells with dendritic morphology were abundant in the epidermis at all times and their migration into the dermis was detected soon after vaccination. All CD207+ LCs were MHCII+ but not all MHCII+ cells in the skin were CD207+. LCs migrated from the dermis in enhanced numbers after vaccination, as detected in dermal exudate populations recovered after in vitro culture of skin biopsies. Elevated numbers of CD207+ LCs were also detected in the sdLN from 24h to 4 days after vaccination. However, compared with other dermal-derived antigen-presenting cells that were CD207−MHCII+ or CD207−CD11c+, the relative numbers of CD207+ cells in the dermal exudate population and in the sdLN were very small. Furthermore, the migration of CD207+ cells after exposure to ‘protective’ radiation-attenuated, compared with ‘non-protective’ normal cercariae, was similar in terms of numbers and kinetics. Together, these studies suggest that CD207+ LCs are only a minor component of the antigen-presenting cell population that migrates from the epidermis and they are unlikely to be important in the priming of protective CD4+ cells in the sdLN.
Highlights
Schistosomiasis is a parasitic disease affecting over 200 million people in many parts of the developing world but as yet an effective vaccine has not been developed
For the first time to our knowledge, we show that schistosome larvae induce the migration of CD207+ Langerhans cells (LCs) from the site of immunisation to the skin-draining lymph nodes (sdLN)
Using the rat mAb F929F3 which recognises a cytoplasmic epitope of CD207, we confirm that LCs are a relatively common cell within the epidermis and they form an evenly distributed network across the epidermal surface (Valladeau et al, 2002; Stoitzner et al, 2003)
Summary
Schistosomiasis is a parasitic disease affecting over 200 million people in many parts of the developing world but as yet an effective vaccine has not been developed. Infection of the mammalian host occurs by penetration of the skin by free-swimming larvae present in contaminated water. Once infective cercariae locate host skin, they enter the stratified epidermis, aided by the secretion of enzymes from the parasites’ acetabular glands (Salter et al, 2002). The schistosome larvae move through the skin until they reach the epidermal–dermal basement membrane, which acts as a barrier prior to their entry into the dermis. The timing of parasite migration through the skin is not agreed (McKerrow and Salter, 2002; Curwen and Wilson, 2003), studies in the mouse suggest that penetration of the epidermis occurs within 30 min and the majority.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
