“Understanding anti-parasitic immune responses by adding complexity to infection model”

Venue: The Murray Room CTIR 2.84 

Host: Dr Henry McSorley

Abstract 

The intestinal roundworm Heligmosomoides bakeri causes chronic infection in susceptible (C57Bl/6) mice; however, repeat (trickle) infection confers immunity and facilitates worm clearance. We show that this acquired immunity is associated with a strong local Th2 response, notably the enhanced production of intestinal granulomas containing eosinophils and macrophages bound to parasite-specific antibody. 

In the natural world rather than the laboratory setting, immune environments are more nuanced. We examined the impact of a mixed Th1 (inflammatory)/Th2 (wound healing) environment on trickle infection-induced immunity. The mixed immune environment resulted in high worm burdens and lower granuloma numbers. Granulomas had decreased proportions of key immune cells (eosinophils and macrophages) and an absence of antibody. Parasite-specific antibodies were also absent from the draining lymph nodes. These data confirm the importance of intestinal granulomas and parasite-specific antibody as worm clearance mechanisms. Our result also highlight why it may be more difficult to clear worms in the field than in the laboratory.