Type I interferons provide additive signals for murine regulatory B cell induction by Schistosoma mansoni eggs

The helminth Schistosoma mansoni (S. mansoni) induces a network of regulatory immune cells, including interleukin (IL)-10-producing regulatory B (Breg) cells. However, the signals required for the development and activation of Breg cells are not well characterized. Recent reports suggest that helminths induce type I interferons (IFN-I), and that IFN-I drives the development of Breg cells in humans. We therefore assessed the role of IFN-I in the induction of Breg cells by S. mansoni. Mice chronically infected with S.mansoni or intravenously injected with S.mansoni soluble egg antigen (SEA) developed a systemic IFN-I signature. Recombinant IFNα enhanced IL-10 production by Breg cells stimulated with S. mansoni soluble egg antigen (SEA) in vitro, while not activating Breg cells by itself. IFN-I signalling also supported ex vivo IL-10 production by SEA-primed Breg cells but was dispensable for activation of S. mansoni egg-induced Breg cells in vivo. These data indicate that while IFN-I can serve as a co-activator for Breg cell IL-10 production, they are unlikely to participate in the development of Breg cells in response to S. mansoni eggs. This article is protected by copyright. All rights reserved.