Rapid induction of IgE responses to a worm cysteine protease during murine pre-patent schistosome infection
1 Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
2 Universidade Vale do Rio Doce (UNIVALE), Governador Valadares, Minas Gerais, Brazil
3 Fundação Nacional de Saúde - FUNASA/BH, Belo Horizonte, Minas Gerais, Brazil
4 Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences (QB3), University of California, San Francisco, 1700 4th St., San Francisco, CA 94158, USA
5 NIH/NIAID/LPD, 4 Center Drive, Building 4, Room B1-06, Bethesda, MD 20892, USA
6 1471 Hopkins Street, Berkeley, CA 94702, USA
7 Leiden Malaria Research Group, Leiden University Medical Centre, afd. Parasitologie, Albinusdreef 2, Kamer P4-35, 2333 ZA Leiden, Netherlands
BMC Immunology 2010, 11:56 doi:10.1186/1471-2172-11-56Published: 15 November 2010
During the pre-patent stage of infection, juvenile Schistosoma blood flukes co-opt signals from the adaptive immune system to facilitate parasite development, but the types of responses that are induced at this early stage of infection, and the parasite antigens they target, have not been characterized.
Through analysis of experimental pre-patent infections, we show that the S. mansoni cysteine protease SmCB1 is rapidly targeted by an antigen-specific IgE response. The induction of this response is independent of schistosome eggs as infection with male or female worms alone also induced SmCB1-specific IgE. We also show that the SmCB1-specific IgE response is dependent on cognate CD4+ T cell help and IL-4, suggesting that pre-patent Th2 responses provide T cell help for the SmCB1-specific IgE response. Finally, exposed human subjects also produced IgE against SmCB1.
Our data demonstrate that, like eggs, schistosome worms also induce functional type 2 responses and that a parasite cysteine protease is an inducer of type 2 responses during the early stages of schistosome infection.