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C J McNeill

Publications and source records attributed to C J McNeill.

5 recordsLinked to original sources
PubMed1983

Dietary lipid modulation of immune responsiveness.

The influence of dietary fat concentration and saturation on blastogenesis, cytotoxicity, antibody response and fatty acid composition of murine splenic lymphocytes was studied. Blastogenesis of lymphocytes from dietarily manipulated mice in response to alloantigens from control mice was significantly greater for those mice fed a diet containing minimal essential fatty acids (EFA) as the only fat source (EFA control) than those fed an EFA-deficient diet. When the dietary fat concentration was increased, blastogenic response decreased compared to the EFA control diet. Lymphocyte-mediated cytotoxicity against allogeneic melanoma cells was greater for mice receiving diets with EFA only than for those deficient in EFA. However, cytotoxicity responses of mice fed additional polyunsaturated fat (PUF) decreased as concentration increased, whereas responses of mice fet the saturated fat (SF) diets decreased only when the dietary fat concentration was greater than 8%. As compared to diets with EFA control, direct plaque-forming cell (PFC) response was decreased for mice fed high levels of PUF and increased for mice fed high levels of SF; however, no difference in the percentage of IgM-positive cells was observed. These changes in PFC response were inversely related to the levels of linoleic acid in the lymphocyte. Thus, high levels of dietary fat, and particularly PUF, suppress lymphocyte functions when EFA requirements are met, whereas low levels (EFA control) intensify these responses. EFA deficiency, however, suppress some lymphocyte responses. Thus, dietary lipids differentially modulate the levels of T- and B-cell responsiveness.

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PubMed1980

Influence of dietary fat concentration and saturation on immune ontogeny in mice.

Dietary fat modulation of immune responsiveness was studied using a murine model subjected to prenatal and postnatal dietary manipulation. The weight of lymphoid associated organs, particularly the spleen, thymus and liver were significantly influenced by dietary fat saturation and concentration whereas other organs studied were not influenced by this manipulation. The serum immunoglobulins IgG1 and IgG2, but not IgM or IgA, increased in mice fed the polyunsaturated fat (PUF) diet as compared to the levels in those mice fed the saturated fat (SF) diet. While dietary manipulation generally did not influence the peripheral differential blood cell counts, the percentage of immunoglobulin positive splenic cells changed with dietary manipulation; the percentage of T cells, however, was not influenced by the experimental diets. In contrast, T-cell blastogenesis was influenced by both saturation and concentration of dietary fat whereas B-cell transformation was influenced by neither variable. Changes in T-cell responses were manifested through changes in the lymphocytes, and not cell numbers; PUF, particularly high levels, suppresses lymphocyte blastogenesis whereas low levels or a deficiency of PUF intensify this response. It is concluded that dietary fats influence the modulation and level of immune function.

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PubMed1979

Effects of low dietary protein concentration and energy deprivation on lymphocyte transformation in melanoma-bearing mice.

Temporal changes in lymphocyte blastogenesis were studied using spleen cells from syngeneic melanoma-bearing and control mice fed various levels of purified diets containing 6, 10 or 30% casein. T-cell blastogenesis was stimulated by the presence of the tumor and these responses changed with the duration of feeding. In addition, protein concentration did not affect T-cell transformation but the level of energy intake influenced concanavalin A induced DNA synthesis. In contrast, the growing melanoma did not influence B-cell transformation whereas a very low level of dietary protein, a low level of energy intake and duration of the dietary manipulation influenced these cells. Tumor weights were generally not affected by the diet except in mice receiving a very low level of energy intake. Thus, we have found that B-cell responses were affected more than those of T-cells and that moderate protein deficiency did not enhance cellular immune responses in syngeneic tumor-bearing and control mice.

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