Interactions among zinc deficiency, energy restriction, immunity and Heligmosomoides polygyrus (Nematoda) infection in mice were investigated. Mice were fed zinc-sufficient (Zn+: 60mg zinc/kg diet), zinc-deficient (Zn$-$: 0.75 mg/kg) or pair-fed (PF) diets. Liver and serum zinc concentrations were reduced in Zn$-$ mice, but zinc content of worms was unaffected by host diet. Both zinc deficiency and energy restriction accelerated worm maturation during a primary infection, but zinc deficiency caused stunting of female worms. Energy restriction led to a anteriorad distribution of worms along the intestine whereas zinc deficiency led to a posteriorad distribution. Enhanced parasite survival in Zn$-$ and PF mice was associated with a decreased immune response in both primary and challenge infections. In the primary infection, spleen cell production of interleukin-4 (IL-4) and interferon-gamma (IFN-$ gamma$), peripheral eosinophilia and serum levels of IgE and IgG1 were reduced by zinc deficiency, whereas the reduced delayed type hypersensitivity (DTH) response and impaired interleukin-5 (IL-5) production were attributed to energy restriction. In the challenge infection, reduced antibody levels (total IgE and IgG1, parasite-specific IgG1 and IgG3) and eosinophilia were attributed to zinc deficiency whereas the higher worm numbers were attributed to a combined effect of zinc deficiency and energy restriction. Although the absolute number of spleen cells was reduced in both Zn$-$ and PF mice, neither deficiency altered the proportion of the cell subpopulations. In vitro functional assays in response to parasite antigen (Ag) revealed that T cell proliferation was reduced by a direct effect of zinc deficiency on T cells, and by the effects of energy restriction on antigen presenting cells (APC). Impaired cytokine production in Zn$-$ mice was more complex. Zinc deficiency reduced T cell function (IL-4 production), energy restriction decreased T cell (IFN-$ gamma$ productio
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.40251 |
| Date | January 1996 |
| Creators | Shi, Hai Ning |
| Contributors | Scott, M. E. (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 | Doctor of Philosophy (Institute of Parasitology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001506060, proquestno: NN12483, Theses scanned by UMI/ProQuest. |
Page generated in 0.0021 seconds