Energy restriction and zinc deficiency impair the functions of murine T cells and antigen-presenting cells during gastrointestinal nematode infection.
This study examined whether the impaired immune responses in zinc deficient- and/or energy-restricted mice exposed to a challenge infection of Heligmosomoides polygyrus might be associated with reduced numbers of spleen cells, altered proportions of spleen cell subpopulations and/or altered function of the T cells or antigen-presenting cells (APC). Female BALB/c mice were given free access to either a zinc-sufficient (60 mg zinc/kg diet, Zn+) or a zinc-deficient diet (0.75 mg zinc/kg diet, Zn-) or were pair-fed (PF) the zinc-sufficient diet. Significant differences in parasite burdens were observed. Worm numbers were lowest in Zn+ mice, intermediate in the PF mice and highest in the Zn- mice, showing that both zinc deficiency and energy restriction reduced protective immunity against the gastrointestinal nematode H. polygyrus. Although the absolute numbers of spleen cells were reduced in both Zn- and energy-restricted (PF) mice, neither deficiency altered the phenotypic distribution of the subpopulations of positive marker cells in the spleen. In vitro functional assays using a 1:1 ratio of APC:T cells showed that T-cell proliferation in response to parasite antigen (Ag) was impaired by a dietary effect of zinc deficiency on T cells and of energy restriction and zinc deficiency on APC function. Consequences of the nutritional deficiencies on cytokine production in response to parasite antigen were more complex: zinc deficiency reduced T-cell function [interleukin-4 and interleukin-5 (IL-4 and IL-5) production], and both nutritional deficits depressed APC functions [IL-4, IL-5, and interferon-gamma (IFN-gamma) production] and T-cell function (IFN-gamma production). Thus, this study showed that zinc deficiency and energy restriction played identifiably distinct roles in regulating host immune responses against the gastrointestinal nematode H. polygyrus.
Shi
H N
HN
Institute of Parasitology, Macdonald Campus of McGill University, Ste. Anne de Bellevue, QC H9X 3V9, Canada.
Scott
M E
ME
Stevenson
M M
MM
Koski
K G
KG
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D002149:Energy Intake; D005260:Female; D005434:Flow Cytometry; D005767:Gastrointestinal Diseases / Q000469:parasitology*; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D009349:Nematode Infections / Q000276:immunology*; D009752:Nutritional Status; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D015032:Zinc / Q000172:deficiency*
D015848:Interleukin-5; D015847:Interleukin-4; D007371:Interferon-gamma; D015032:Zinc