Protein deficiency may increase susceptibility to gastrointestinal (GI) parasitic infections, possibly as a result of impaired systemic and/or intestinal effector responses induced by downregulation of Th2 cytokines and/or upregulation of Th1 cytokines. To test this hypothesis, female BALB/c mice (n = 18/diet) were fed a control (24%), marginal (7%), or deficient (3%) protein diet and given a challenge infection with the GI nematode, Heligmosomoides polygyrus. The 3% mice had higher worm burdens at 1, 2 and 4 weeks post-challenge infection (pci), lower increases in serum IgE, reduced intestinal eosinophilia, and depressed mucosal mast cell proliferation and activation at 1 to 2 weeks pci. To determine whether these suppressed effector responses in the 3% mice were associated with altered spleen and mesenteric lymph node (MLN) cytokine profiles, cells were restimulated in vitro with parasite antigen and cytokine concentrations were measured. Deficient MLN cells secreted significantly less IL-4 and more IFN-gamma at 1--2 weeks pci than did control MLN cells. Deficient spleen cells also secreted more IFN-gamma at 2 weeks pci compared with control spleen cells. From RT-PCR analyses, the 3% mice also had lower IL-4 mRNA expression in spleen and MLN at 1--2 weeks pci. Our study supports the hypothesis that protein deficiency exacerbates the survival of a GI nematode parasite by decreasing IL-4 (Th2) and increasing IFN-gamma (Th1) early in the infection, leading to reduced gut and systemic Th2 effector responses.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20576 |
| Date | January 1998 |
| Creators | Ing, Rebecca Yat Loo, 1971- |
| Contributors | Scott, Marilyn E. (advisor), Koski, Kristine G. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Institute of Parasitology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001643069, proquestno: MQ44186, Theses scanned by UMI/ProQuest. |
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