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Results for “Immune function”

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At least 1,639 records · Page 91Linked to original sources
PubMed1976

Age-associated involution of cellular immune function. I. Accelerated decline of mitogen reactivity of spleen cells in adult thymectomized mice.

Autoimmune-susceptible (A/J and C57BL/6J) and nonautoimmune-susceptible (DBA/1J) strains of mice were adult thymectomized (aTx). Groups of mice treated by aTx, aTx and 330 rads (R), aTx and 650 R, and 330 R OR 650 R only, were compared to normal age-matched control (normal and sham Tx) mice. T cell functions were then followed as measured by in vitro spleen cell responsiveness to the T cell mitogens phytohemagglutinin (PHA) and staphylococcal enterotoxin B (SEB) in a long-term study. A decline in spleen cell responsiveness with natural aging up to 18 months of age was seen to PHA in all three strains and to SEB in A/J and C57BL/J mice. Adult Tx alone was followed by an accelerated decline in spleen cell responsiveness to PHA and SEB in all three strains of mice. Irradiation combined with aTx-reduced spleen cell responsiveness to SEB in A/J and DBA/1J mice. Irradiation with or without aTx diminished the bone marrow stem cell pool as measured by exogenous colony-forming units, and the hematocrit of all three strains of mice. Thus, the natural decline in cellular immunity with aging was accelerated by aTx in both autoimmune-susceptible and non-autoimmune-susceptible strains of mice. These results emphasize that physiologic thymic function(s) must continue throughout life in order to maintain T cell function.

Aging↗
PubMedDate not supplied

Neurosurgical stress and immune function.

The present study was carried out in 31 neurosurgical patients with unaffected consciousness and concerned by the severity of their condition. The severity of stress was established by the comparison between the pre- and postoperative peripheral blood lymphocyte populations and subpopulations (B, T, Th lymphocytes, serum complement and circulating immune complexes). The peripheral blood lymphocyte populations and subpopulations were determined by the technique of sheep red blood cell rosette. Circulating immune complexes were determined by precipitation of polyethylene glycol (PEG, M = 6000) whereas the serum complement by the usual 50% hemolytic method. Our data show that the decrease in Th cells and the consecutive diminution of antibody production is a cause of lower resistance against cancer and infections.

Adult↗
PubMed1994

Immunoglobulin levels and cellular immune function in lead exposed workers.

The immunological status of lead acid battery workers with blood lead levels and urinary delta-aminolevulinic acid (ALA-U) concentrations ranging from safe to toxic levels has been examined and compared with those of non-exposed, age and sex matched controls. No differences in the serum concentrations of IgG, IgA and IgM between the populations were observed and there existed no correlation between blood lead level or ALA-U concentrations and serum immunoglobulin levels. In addition assessment was made of the capacity of peripheral blood mononuclear cells to respond to the mitogen phytohaemagglutinin (PHA), a correlate of T cell function. As before, there was no difference between exposed and control populations and no correlation between reactivity and blood lead concentration. Our data suggest that chronic exposure to lead fail to compromise lymphocyte function in man.

Aminolevulinic Acid↗
PubMed1987

Nutrition and immune function in the geriatric population.

Aging in experimental animals and in man is associated with a significant defect of helper/inducer T-lymphocytes. This quantity deficiency is paralleled by a qualitative deficiency of T-lymphocyte number and function. Similar defects have been observed in protein calorie malnutrition and zinc deficiency, and there is evidence that both may exist in the aged ill and perhaps even in aged healthy individuals. Nutritional support improves the immune defect in aged ill patients and it may be of value in improving this deficiency, even when administered to aged healthy subjects.

Age Factors↗
PubMed1989

Effect of CI-949 and CI-959 on immune function and lymphoid organs in rats.

The immunotoxic properties of two experimental antiallergic drugs, CI-949 and CI-959, were investigated. Wistar rats were gavaged once (CI-949) or twice (CI-959) daily for 21 days with the drugs. Immunotoxicity was assessed using the enzyme-linked immunoabsorbant assay (ELISA) for humoral immunity, a delayed-type hypersensitivity (DTH) procedure for cell-mediated immunity, and natural killer cell (NKC) activity to evaluate spontaneous cytotoxicity. Ratios of body weight to spleen, thymus, liver and kidney weights were determined. Routine histopathology was performed on lymphoid tissue and other body organs. Although 100 mg/kg/day of CI-949 had some stimulating effect on antibody production and NKC cytotoxicity, no consistent immunomodulation was apparent. Except for a significant increase in liver weight at the 100 mg/kg dose of CI-949, no other toxic effects were observed. In contrast to CI-949, CI-959 significantly (P less than 0.05) suppressed antibody production at the 100 mg/kg dose and impaired the DTH reaction, although not significantly. Natural killer cell cytotoxicity was unaffected by 100 mg/kg CI-959. Decreased body weight and histopathological lesions were observed in the thymus and spleen of rats administered 100 mg/kg CI-959. These lesions ranged from mild to severe lymphoid depletion which was also reflected in significantly (P less than 0.05) reduced spleen and thymus organ weight to body weight ratios. Since 100 mg/kg of CI-959 produced toxicological and pathological alterations in the exposed rats, these data suggest that CI-959 is not highly or specifically immunotoxic at dosages lower than those that alter conventional toxicological parameters used in new drug testing programs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

Contribution of respiratory burst activity to innate immune function and the effects of disease status and agent on chemiluminescence responses by ruminant phagocytes in vitro.

The mechanisms of interaction between phagocytes and different bacteria that help resolve lung infections or contribute to lung pathology are poorly defined. Alveolar phagocytes (resident macrophages and recruited neutrophils) make a major contribution to innate immunity by mounting a respiratory burst that helps kill internalised bacteria. However, this ability may be altered during or after exposure to infection. This review considers the application and limitations of a variety of analytical methods for oxygen-dependent mechanisms of respiratory burst in phagocytes initiated by soluble and particulate activators. Particular reference is given to the study in vitro of phagocytes from healthy and diseased ruminants during either natural infection with Mycobacterium avium paratuberculosis or experimental infection with Pasteurella multocida or Mannheimia haemolytica.

Animals↗
PubMed2006

Gliotoxin-mediated suppression of innate and adaptive immune functions directed against Listeria monocytogenes.

Gliotoxin is an immunosuppressive apoptogenic mycotoxin produced by a number of fungi including important human pathogens as Aspergillus fumigatus. In order to elucidate the potential role of gliotoxin as immunoevasive fungal virulence factor we studied the effects of gliotoxin on the innate and adaptive T cell-mediated immune response against the facultatively intracellular bacterium Listeria monocytogenes. Gliotoxin induced apoptosis of bone marrow-derived macrophages, dendritic cells and CD8 T cells in a dose- and cell type-dependent manner. In vitro the apoptogenic effect of gliotoxin correlated with a strong reduction of TNF-alpha and interleukin (IL)-12 production by dendritic cells and bone marrow-derived macrophages infected with L. monocytogenes and in the case of infected macrophages also in reduced NO-production and recognition by L. monocytogenes-specific CD8 T cells. Further gliotoxin pre-treatment of CD8 T cells reduced target cell lysis. In vivo, treatment of mice with gliotoxin increased the bacterial burden during the innate and the adaptive phase of primary L. monocytogenes infection. Taken together, these results demonstrate the suppressive effects of gliotoxin on the innate and also on the adaptive T cell-mediated antilisterial immunity.

Animals↗
PubMed1990

Augmentation of mouse immune functions by dietary restriction: an investigation up to 1 year of age.

Mice fed a 40% restricted diet until 1 year of age showed a 35% drop in body weight and markedly lower weights in the central lymphoid organs such as spleen and thymus than those of unrestricted mice. In contrast, the percentage of splenic Thy 1.2+ T cells was dramatically increased by dietary restriction. Splenic Ly 1+ T cells were also increased in the restricted mice. Spleen cells of the restricted mice revealed significantly higher responses not only in macrophage (MP)-dependent responses such as concanavalin A response and mixed-lymphocyte reaction but also in MP-independent T cell responses to recombinant interleukin 2 even at 1 year of age. These results strongly suggest that dietary restriction causes an enrichment of Thy 1.2+ T cells in spleen and augments the functions of T cells in mice.

Age Factors↗
PubMed1987

Immune function: relationship of nutrition and disease control. Vitamin A and beta-carotene on host defense.

Even though the protective role played by vitamin A and beta-carotene against numerous diseases has been clearly demonstrated, the exact mechanism by which they afford this protection is not completely understood. Impairment of the animal's immune system resulting from the vitamin deficiency may account for increased susceptibility to infection. This article attempts to draw from available information on the effects of vitamin A and beta-carotene on specific and nonspecific host defense mechanisms as they relate to disease.

Animal Diseases↗