Cryptosporidium parvum infection rapidly induces a protective innate immune response involving type I interferon.
Type II interferon (IFN), IFN-gamma, is important in innate immunity to the intestinal protozoan parasite Cryptosporidium species, which infects epithelial cells (enterocytes). This investigation is, to our knowledge, the first to characterize the role of type I IFN in innate immunity to this parasite. Pretreatment of human or murine enterocyte cell lines with IFN-alpha/beta inhibited parasite development, and we identified that a key mechanism of cytokine action was to prevent parasite invasion of enterocytes. IFN-alpha/beta was rapidly expressed by infected murine enterocytes and also by bone marrow-derived dendritic cells that were exposed to live parasites. Treatment of neonatal severe combined immunodeficiency mice with anti-IFN-alpha/beta neutralizing antibodies before infection increased oocyst reproduction, as measured at the peak of infection, and parasite numbers in gut epithelium were also increased 2 days after infection. The latter observation correlated with strong intestinal expression of both IFN-alpha and IFN-beta messenger RNA within 24 h after infection. Treatment with anti-IFN-alpha/beta, however, did not reduce early expression of IFN-gamma. These findings identify a novel early innate host response against Cryptosporidium parvum involving IFN-alpha/beta.
Barakat
Farah M
FM
Queen Mary University of London, Institute of Cell and Molecular Science, Centre for Gastroenterology, Barts and the London School of Medicine and Dentistry, 4 Newark Street, London, United Kingdom.
McDonald
Vincent
V
Foster
Graham R
GR
Tovey
Michael G
MG
Korbel
Daniel S
DS
D000818:Animals; D018938:Caco-2 Cells; D003457:Cryptosporidiosis / Q000276:immunology*; D016785:Cryptosporidium parvum / Q000276:immunology*; D020895:Enterocytes / Q000276:immunology* / Q000469:parasitology; D006801:Humans; D007113:Immunity, Innate; D016898:Interferon-alpha / Q000235:genetics / Q000276:immunology*; D016899:Interferon-beta / Q000235:genetics / Q000276:immunology*; D051379:Mice; D012333:RNA, Messenger
D016898:Interferon-alpha; D012333:RNA, Messenger; D016899:Interferon-beta