Rajesh M. Valanparambil1, Yovany Moreno2, Armando Jardim2 , Timothy G. Geary2 and Mary M.
Stevenson1. 1Department of Medicine and 2Institute of Parasitology McGill University.
Immunomodulatory proteins derived from a gastrointestinal nematode as novel therapies for immunemediated diseases.
Infection with Heligmosomoides polygyrus (Hp), a gastrointestinal nematode of mice, potently
suppresses immune responses to unrelated antigens irrespective of their CD4+ Th cell affinity.
Previously, we showed that Hp-derived excretory-secretory products (HpES) modulate the antigen
presenting function of dendritic cells to suppress Th1 and Th2 responses and induce regulatory T cells.
This mechanism is considered to be responsible for the immunomodulatory effects of this parasite on
immune responses to unrelated antigens including immune-mediated diseases, such as inflammatory
bowel disease (IBD), multiple schlerosis (MS), and lung allergy. To identify and characterize the
molecule(s) in HpES that have immunomodulatory properties, we performed HPLC (size exclusion
chromatography) to separate HpES proteins based on molecular weight. The immunosuppressive activity
of the separated proteins was assessed by measuring IL-12p70 secretion by bone marrow-derived
dendritic cells (BMDC) pre-treated with ES fractions prior to simulation with CpG-ODN, a TLR9 ligand.
We identified 12 fractions that suppressed IL-12p70 induction by CpG-ODN. These fractions were
pooled and subjected to ion-exchange chromatography using an anionic exchange column. Testing of
these fractions on BMDC stimulated with CpG-ODN showed that 3 of the fractions suppressed IL-12p70
secretion. Analysis of these fractions by LC-MS/MS identified a total of 9 candidate proteins. Our goal is
to further characterize, clone, and purify the candidate proteins identified, to confirm their
immunomodulatory effects on DC polarization of Th cells in vitro and in vivo, and to test their
therapeutic potential in mouse models of IBD, MS, and lung allergy. (Supported by CIHR and NSERC).