Vitamin E Scaffolds of pH-Responsive Lipid Nanoparticles as DNA Vaccines in Cancer and Protozoan Infection.

DNA vaccinations are promising strategies for treating diseases that require cellular immunity (i.e., cancer and protozoan infection). Here, we report on the use of a liposomal nanocarrier (lipid nanoparticles (LNPs)) composed of an SS-cleavable and pH-activated lipidlike material (ssPalm) as an in vivo DNA vaccine. After subcutaneous administration, the LNPs containing an ssPalmE, an ssPalm with vitamin E scaffolds, elicited a higher gene expression activity in comparison with the other LNPs composed of the ssPalms with different hydrophobic scaffolds. Immunization with the ssPalmE-LNPs encapsulating plasmid DNA that encodes ovalbumin (OVA, a model tumor antigen) or profilin (TgPF, a potent antigen of Toxoplasma gondii) induced substantial antitumor or antiprotozoan effects, respectively. Flow cytometry analysis of the cells that had taken up the LNPs in draining lymph nodes (dLNs) showed that the ssPalmE-LNPs were largely taken up by macrophages and a small number of dendritic cells. We found that the transient deletion of CD169+ macrophages, a subpopulation of macrophages that play a key role in cancer immunity, unexpectedly enhanced the activity of the DNA vaccine. These data suggest that the ssPalmE-LNPs are effective DNA vaccine carriers, and a strategy for avoiding their being trapped by CD169+ macrophages will be a promising approach for developing next-generation DNA vaccines.

Cytokine storm in aged people with CoV-2: possible role of vitamins as therapy or preventive strategy.

BACKGROUND: In December 2019, a novel human-infecting coronavirus, SARS-CoV-2, had emerged. The WHO has classified the epidemic as a "public health emergency of international concern". A dramatic situation has unfolded with thousands of deaths, occurring mainly in the aged and very ill people. Epidemiological studies suggest that immune system function is impaired in elderly individuals and these subjects often present a deficiency in fat-soluble and hydrosoluble vitamins. METHODS: We searched for reviews describing the characteristics of autoimmune diseases and the available therapeutic protocols for their treatment. We set them as a paradigm with the purpose to uncover common pathogenetic mechanisms between these pathological conditions and SARS-CoV-2 infection. Furthermore, we searched for studies describing the possible efficacy of vitamins A, D, E, and C in improving the immune system function. RESULTS: SARS-CoV-2 infection induces strong immune system dysfunction characterized by the development of an intense proinflammatory response in the host, and the development of a life-threatening condition defined as cytokine release syndrome (CRS). This leads to acute respiratory syndrome (ARDS), mainly in aged people. High mortality and lethality rates have been observed in elderly subjects with CoV-2-related infection. CONCLUSIONS: Vitamins may shift the proinflammatory Th17-mediated immune response arising in autoimmune diseases towards a T-cell regulatory phenotype. This review discusses the possible activity of vitamins A, D, E, and C in restoring normal antiviral immune system function and the potential therapeutic role of these micronutrients as part of a therapeutic strategy against SARS-CoV-2 infection.

Regulatory role of vitamin E in the immune system and inflammation.

Vitamin E, a potent lipid-soluble antioxidant, found in higher concentration in immune cells compared to other cells in blood, is one of the most effective nutrients known to modulate immune function. Vitamin E deficiency has been demonstrated to impair normal functions of the immune system in animals and humans, which can be corrected by vitamin E repletion. Although deficiency is rare, vitamin E supplementation above current dietary recommendations has been shown to enhance the function of the immune system and reduce risk of infection, particularly in older individuals. The mechanisms responsible for the effect of vitamin E on the immune system and inflammation have been explored in cell-based, pre-clinical and clinical intervention studies. Vitamin E modulates T cell function through directly impacting T cell membrane integrity, signal transduction, and cell division, and also indirectly by affecting inflammatory mediators generated from other immune cells. Modulation of immune function by vitamin E has clinical relevance as it affects host susceptibility to infectious diseases such as respiratory infections, in addition to allergic diseases such as asthma. Studies examining the role of vitamin E in the immune system have typically focused on α-tocopherol; however, emerging evidence suggests that other forms of vitamin E, including other tocopherols as well as tocotrienols, may also have potent immunomodulatory functions. Future research should continue to identify and confirm the optimal doses for individuals at different life stage, health condition, nutritional status, and genetic heterogeneity. Future research should also characterize the effects of non-α-alpha-tocopherol vitamin E on immune cell function as well as their potential clinical application. © 2018 IUBMB Life, 71(4):487-494, 2019.

Immune boosting role of vitamin E against pulmonary tuberculosis.

Tuberculosis is one of the leading causes of mortality in Pakistan which is linked with malnutrition and weak immunity. Such people are more prone to chronic infections including TB. The current study aimed to assess the effect of supplementation of Vitamin E on the immune status of human subjects against pulmonary tuberculosis. A total of 80 patients with pulmonary TB were divided into treatment group (vitamin E) and control group (Anti-tuberculosis regime). Presence of acid fast bacilli in sputum sample, Erythrocyte sedimentation rate, total leucocytes counts, body mass index and mid arm muscle circumference (MAMC) were recorded as per standard protocol. Levels of vitamin E, IgG, IgM and T-Cell count were determined before and after treatment. The results showed that 16% males and 33% females were underweight who consumed 1145 kcal energy instead of 2270 kcal per day and 19.5 gram protein instead of 78.6 grams. A non significant effect of vitamin E on ESR and TLC values was observed but significant increase in level of immunoglobulins (IgG, IgM) and T-cell types (CD4+ and CD8+) was observed in patients as compared to control group. Results indicate that vitamin E plays important role in enhancing immunity of patients against TB.

Vitamin E deficiency depressed fish growth, disease resistance, and the immunity and structural integrity of immune organs in grass carp (Ctenopharyngodon idella): Referring to NF-κB, TOR and Nrf2 signaling.

This study investigated the effects of dietary vitamin E on growth, disease resistance and the immunity and structural integrity of head kidney, spleen and skin in grass carp (Ctenopharyngodon idella). The fish were fed six diets containing graded levels of vitamin E (0, 45, 90, 135, 180 and 225 mg/kg diet) for 10 weeks. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila. The results showed that compared with optimal vitamin E supplementation, vitamin E deficiency caused depressed growth, poor survival rates and increased skin lesion morbidity in grass carp. Meanwhile, vitamin E deficiency decreased lysozyme and acid phosphatase activities, complement component 3 and complement component 4 contents in the head kidney, spleen and skin of grass carp (P < 0.05). Moreover, vitamin E deficiency down-regulated antimicrobial peptides (Hepcidin, liver-expressed antimicrobial peptide-2A, -2B, ß-defensin), IL-10, TGFß1, IκBα, TOR and S6K1 mRNA levels (P < 0.05) and up-regulated IL-1ß, IL-6, IL-8, IFN-γ2 and TNFα, NF-κB p65, IKKα, IKKß and 4EBP1 (not in the head kidney) mRNA levels (P < 0.05). In addition, vitamin E deficiency caused oxidative damage, decreased superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and glutathione reductase (GR) activities, and down-regulated the mRNA levels of antioxidant enzymes and signaling molecules Nrf2 (P < 0.05). Vitamin E deficiency also induced apoptosis by up-regulating capase-2, -3, -7, and -8 mRNA levels in the head kidney, spleen and skin of grass carp. In conclusion, this study indicated that dietary vitamin E deficiency depressed fish growth, impaired the immune function and disturbed the structural integrity of the head kidney, spleen and skin in grass carp, but optimal vitamin E supplementation can reverse those negative effects in fish. The optimal vitamin E requirements for young grass carp (266.39-1026.63 g) to achieve optimal growth performance and disease resistance based on the percent weight gain (PWG) and skin lesion morbidity were estimated to be 116.2 and 130.9 mg/kg diet, respectively. Meanwhile, based on immune indicator (LA activity in the head kidney) and antioxidant indicator (protection of spleen against MDA), the optimal vitamin E requirements for young grass carp were estimated to be 123.8 and 136.4 mg/kg diet, respectively.

Suppression of NLRP3 inflammasome by γ-tocotrienol ameliorates type 2 diabetes.

The Nod-like receptor 3 (NLRP3) inflammasome is an intracellular sensor that sets off the innate immune system in response to microbial-derived and endogenous metabolic danger signals. We previously reported that γ-tocotrienol (γT3) attenuated adipose tissue inflammation and insulin resistance in diet-induced obesity, but the underlying mechanism remained elusive. Here, we investigated the effects of γT3 on NLRP3 inflammasome activation and attendant consequences on type 2 diabetes. γT3 repressed inflammasome activation, caspase-1 cleavage, and interleukin (IL) 1ß secretion in murine macrophages, implicating the inhibition of NLRP3 inflammasome in the anti-inflammatory and antipyroptotic properties of γT3. Furthermore, supplementation of leptin-receptor KO mice with γT3 attenuated immune cell infiltration into adipose tissue, decreased circulating IL-18 levels, preserved pancreatic ß-cells, and improved insulin sensitivity. Mechanistically, γT3 regulated the NLRP3 inflammasome via a two-pronged mechanism: 1) the induction of A20/TNF-α interacting protein 3 leading to the inhibition of the TNF receptor-associated factor 6/nuclear factor κB pathway and 2) the activation of AMP-activated protein kinase/autophagy axis leading to the attenuation of caspase-1 cleavage. Collectively, we demonstrated, for the first time, that γT3 inhibits the NLRP3 inflammasome thereby delaying the progression of type 2 diabetes. This study also provides an insight into the novel therapeutic values of γT3 for treating NLRP3 inflammasome-associated chronic diseases.

Effect of dietary vitamin E on growth, muscle composition, hematological and immunological parameters of sub-yearling beluga Huso huso L.

This study was designed to determine the effect of dietary vitamin E on growth, some hematological and immunological parameters and muscle proximate analysis of beluga Huso huso. Experimental fish were fed practical diets supplemented with 0, 25, 50, 100, 200 and 400 mg Dl-all-rac-α-tocopherol acetate kg diet(-1) for 8 weeks. 360 fish (mean initial weight 49.7 ± 0.1 g) were distributed into eighteen 785 L circular concrete tanks and each diet was fed to triplicate groups of fish. At the end of experiment (8 weeks), growth parameters such as final weight (FW), weight gain (WG), total length (TL), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), condition factor (CF), hepatosomatic index (HSI), muscle composition, and some physiological indicators, including hematological and immunological parameters, such as hematocrit (Hct), total leukocyte count (WBC), lymphocyte, neutrophil, eosinophil and monocyte, cortisol, glucose, erythrocyte fragility, lysozyme and complement activity were determined. FW, WG, SGR, PER and CF in fish fed unsupplemented vitamin E were significantly lower than those fish fed the other five diets. However FW and PER in fish fed control diet had not significant differences with fish fed at 400 mg kg(-1). FCR were significantly higher in fish fed control diet than other groups. TL and survival rate had no significant differences among fish groups. HSI in fish fed 0 and 25 mg vitamin E kg diet(-1) were significantly lower than the other treatments. Muscle composition analysis showed no significant differences among the treatments. Erythrocyte fragility, Hct, WBC, lymphocyte, neutrophil, eosinophil and monocyte, lysozyme and complement activities were not significant. Also cortisol and glucose concentrations had not significant differences between treatments. Results indicated that vitamin E had no significantly effect on muscle proximate analysis, hematological and immunological parameters of sub-yearling beluga but has a direct effect on growth performance of beluga sturgeon and this vitamin is an essential nutrient required for normal growth in this species.

Immune-boosting role of vitamins D, C, E, zinc, selenium and omega-3 fatty acids: Could they help against COVID-19?

The world is currently in the grips of the coronavirus disease (COVID-19) pandemic, caused by the SARS-CoV-2 virus, which has mutated to allow human-to-human spread. Infection can cause fever, dry cough, fatigue, severe pneumonia, respiratory distress syndrome and in some instances death. COVID-19 affects the immune system by producing a systemic inflammatory response, or cytokine release syndrome. Patients with COVID-19 have shown a high level of pro-inflammatory cytokines and chemokines. There are currently no effective anti-SARS-CoV-2 viral drugs or vaccines. COVID-19 disproportionately affects the elderly, both directly, and through a number of significant age-related comorbidities. Undoubtedly, nutrition is a key determinant of maintaining good health. Key dietary components such as vitamins C, D, E, zinc, selenium and the omega 3 fatty acids have well-established immunomodulatory effects, with benefits in infectious disease. Some of these nutrients have also been shown to have a potential role in the management of COVID-19. In this paper, evidence surrounding the role of these dietary components in immunity as well as their specific effect in COVID-19 patients are discussed. In addition, how supplementation of these nutrients may be used as therapeutic modalities potentially to decrease the morbidity and mortality rates of patients with COVID-19 is discussed.

The immunoregulatory role of vitamins A, D and E in patients with primary Sjogren's syndrome.

OBJECTIVE: The aim of the present study was to investigate the immunomodulating role of fat-soluble vitamins in 25 patients with primary SS (pSS) and 15 healthy individuals. METHODS: Plasma levels of vitamins A, D and E were determined by HPLC. Peripheral NK, NK T cells, T-cell subsets, B cells, IL-10 producing Tr1 cells, CD4(+)CD25(+) Treg cells and Th17 were determined by flow cytometry. Various Th1- and Th2-soluble cytokines were assessed by ELISA, whereas intracytoplasmic cytokines (IFN-gamma, IL-4, -10 and -17) were measured by flow cytometry. Correlation was assessed between vitamin levels and immunological and clinical parameters. RESULTS: Vitamin A levels did not differ between patients and controls, yet in patients with extraglandular manifestations (EGMs) a significant decrease in vitamin A levels was apparent compared with pSS patients without EGMs (P = 0.005). Vitamin E levels were increased in patients compared with controls (P = 0.004), whereas vitamin D levels were similar in pSS and control subjects. In patients, vitamin A showed a positive correlation with both NK cell (P = 0.038) and Th17 cell (P = 0.025), and a negative correlation with Schirmer's test values (P = 0.035). Positive correlation was found between vitamin E and NK cells (P = 0.043), Th1 cells (P = 0.049) and the Th1/Th2 ratio (P = 0.043). In the control group, we found correlation between vitamin E and serum IL-10 levels (P = 0.003). CONCLUSIONS: Our data suggest that fat-soluble vitamins may be important in immunoregulatory processes in patients with pSS.

NUTRITION AND HEALTH: COMPANION ANIMAL APPLICATIONS: Functional nutrition in livestock and companion animals to modulate the immune response.

Advances in the understanding of how the immune system functions in response to diet have altered the way we think about feeding livestock and companion animals on both the short (weeks/months) and long-term (years) timelines; however, depth of research in each of these species varies. Work dedicated to understanding how immune function can be altered with diet has revealed additional functions of required nutrients such as vitamins D and E, omega-3 polyunsaturated fatty acids (PUFA), and minerals such as zinc, while feed additives such as phytogenics and probiotics add an additional layer of immunomodulating potential to modern diets. For certain nutrients such as vitamin D or omega-3 PUFA, inclusion above currently recommended levels may optimize immune function and reduce inflammation, while for others such as zinc, additional pharmacological supplementation above requirements may inhibit immune function. Also to consider is the potential to over-immunomodulate, where important functions such as clearance of microbial infections may be reduced when supplementation reduces the inflammatory action of the immune system. Continued work in the area of nutritional immunology will further enhance our understanding of the power of nutrition and diet to improve health in both livestock and companion animals. This review collects examples from several species to highlight the work completed to understand how nutrition can be used to alter immune function, intended or not.

Immunological and pathological effects of vitamin E with Fetomune Plus® on chickens experimentally infected with avian influenza virus H9N2.

Avian influenza virus (AIV) H9N2 infection causes economic losses on poultry farms, and immunostimulants are essential for improving chicken immunity. This study evaluated the immunological and pathological effects of vitamin E with Fetomune Plus® (a commercial product based on a yeast extract and vitamins) on chickens experimentally infected with AIV H9N2. Three groups of white Hy-Line chicks were included. The G1 group was kept as an uninfected untreated control, the G2 group was intranasally infected with the AIV H9N2 strain (0.5 ml of 106 50% egg infectious dose (EID50)), and the G3 group was infected and treated with vitamin E (200 mg/kg of diet) and Fetomune Plus® (1 ml/liter of drinking water) for four weeks. The gene expression of interferon-gamma (IFN-γ), interleukin (IL)-6, and IL-2 was determined at 3, 5 and 7 days post-infection (PI). Virus shedding titers and rates and haemagglutination inhibition (HI) antibody titers were detected. Clinical signs, mortalities and post-mortem lesions were recorded. The birds were weighed, and relative organ weights were calculated. Tissue specimens were taken for histopathological examination and immunohistochemistry (IHC). The expression of IFN-γ in the duodenum revealed a significant increase in G2 compared to G3 at 3 days PI, while the duodenal and splenic expression of IL-6 was significantly increased in G2 compared to G3 at 5 days PI. IL-2 was overexpressed in the duodenum in G3 compared to G2 at 3 and 5 days PI. A significant decrease (P ≤ 0.05) in the virus shedding titer and an increase in the HI titers were detected in G3 compared to G2. The clinical signs and the mortality rate were clearly appeared in G2 than in G3. By IHC, lower H9N2 staining intensity was observed in the examined organs from G3 than in those from G2. In conclusion, as a first report, vitamin E with Fetomune Plus® supplementation for four weeks could improve the immunological and pathological effects of H9N2 infection on chickens.

Role of antioxidants and trace elements in health and immunity of transition dairy cows.

A number of antioxidants and trace minerals have important roles in immune function and may affect health in transition dairy cows. Vitamin E and beta-carotene are important cellular antioxidants. Selenium (Se) is involved in the antioxidant system via its role in the enzyme glutathione peroxidase. Inadequate dietary vitamin E or Se decreases neutrophil function during the perpariturient period. Supplementation of vitamin E and/or Se has reduced the incidence of mastitis and retained placenta, and reduced duration of clinical symptoms of mastitis in some experiments. Research has indicated that beta-carotene supplementation may enhance immunity and reduce the incidence of retained placenta and metritis in dairy cows. Marginal copper deficiency resulted in reduced neutrophil killing and decreased interferon production by mononuclear cells. Copper supplementation of a diet marginal in copper reduced the peak clinical response during experimental Escherichia coli mastitis. Limited research indicated that chromium supplementation during the transition period may increase immunity and reduce the incidence of retained placenta.

Influence of immunomodulation on the development of Listeria monocytogenes infection in aged guinea pigs.

We investigated the impact of immunomodulation on the development of listeriosis within an aged population of guinea pigs after an intragastric challenge with Listeria monocytogenes. Supplementation with vitamin E for 35 days significantly increased the level of cytotoxic T cells (CD8(+)), while treatment with cyclosporin A resulted in a 25% decrease of CD8(+) T cells. In the animals receiving the low dose (10(2) CFU) of L. monocytogenes, 50% of the control-group animals became infected. Only 22% of animals receiving the orthomolecular dose of vitamin E became infected, whereas animals that were immunosuppressed had an infection rate of 89%. In the immunosuppressed group three animals (16%) developed listerial infection with a quantifiable bacterial level of 0.3-3 log CFU g(-1) of organ in the spleen and liver. In the high-dose study, the population of L. monocytogenes was consistently 1 log CFU g(-1) lower in the spleen or liver of the vitamin E-supplemented group, compared with the control and cyclosporin A-treated animals. At day 4, a significant increase in the levels of CD8(+) during listerial infection occurred in vitamin E-supplemented animals, suggesting an increased ability to produce CD8(+) T cells. The results suggest that immunomodulation of the host can influence listerial infection within an aged population of guinea pigs.

Investigating the potential role of vitamin E in modulating the immunosuppressive effects of tylvalosin and florfenicol in broiler chickens.

Tylvalosin (TVS) is a third-generation macrolide drug used for prophylaxis and treatment of mycoplasma, however; it is supposed to possess an immunosuppressive effect. In the current study, the immunosuppressive effect of TVS and florfenicol (FFC) and the potential immunomodulatory role of Vit E were investigated. The experiment included one day old chick groups treated with either TVS, FFC, Vit E, TVS/Vit E, FFC/Vit E and control non-treated group. Chicks were vaccinated with inactivated H9N2 avian influenza (AI) vaccine and humoral antibody titers to viral antigen as well as innate immunity (serum lysozyme activity and nitric oxide levels) were evaluated. Total and differential leucocytic counts, serum liver enzymes level, blood leucocytic DNA damage and cellular area percentages within the lymphoid organs were also screened. Treatment with TVS and FFC significantly decreased immune response of chickens while treatment with Vit E improved the humoral immune response at 4 and 5weeks post-vaccination. Vit E also significantly increased the cellular immune response. The combination of Vit E with either TVS or FFC modulated their immunosuppressive effect and resulted in mild immunostimulatory effects. TVS alone induced a genotoxic effect on chickens' blood leucocytes and the genotoxicity was inhibited by combination of TVS with Vit E. Histopathology revealed that chickens treated with either TVS or FFC exhibited toxic effect on the lymphatic tissues.

Immunomodulatory therapy for chronic hepatitis B virus infection.

Hepatitis B virus (HBV) is one of the most prevalent viral pathogens of man with around 350 million chronically infected patients. It has been postulated that in persistently infected individuals the HBV-specific immune response is too weak to eliminate HBV from all infected hepatocytes, but sufficiently strong to continuously destroy HBV-infected hepatocytes and to induce chronic inflammatory liver disease. The primary aim in the treatment of chronic hepatitis B is to induce sustained disease remission and prevent serious complications like liver failure and/or hepatocellular carcinoma. The recent emergence of drug-resistant HBV mutants and post-treatment relapse as a consequence of nucleoside analogue monotherapy emphasizes that the principal goal should be to stimulate a successful immune response. In this paper we will focus on the immune response to HBV and we will review reported data on immunotherapeutic strategies like immunomodulatory drugs (cytokines and Thymic derivates) and vaccine therapies using currently available recombinant anti-HBV vaccines, lipopeptide-based T cell vaccine and newly developed genetic vaccines.

Vitamin C in breast milk may reduce the risk of atopy in the infant.

OBJECTIVE: To assess the effects of maternal dietary and supplement intake of vitamins C and E on breast milk antioxidant composition (vitamin C, alpha-tocopherol and beta-carotene) and their protective potential against the development of atopy in the infant. DESIGN, SUBJECTS AND METHODS: Mothers with atopic disease were recruited at the end of gestation and maternal sensitization was assessed by skin-prick testing. The 4-day food records of the mothers and breast milk samples were collected at the infants' age of 1 month. Infants' atopy was defined by the presence of atopic dermatitis during the first year of life and a positive skin-prick test reaction at 12 months of age (n=34). RESULTS: Maternal intake of vitamin C in diet but not as supplement was shown to determine the concentration of vitamin C in breast milk. A higher concentration of vitamin C in breast milk was associated with a reduced risk of atopy in the infant (OR=0.30; 95% CI 0.09-0.94; P=0.038), whereas alpha-tocopherol had no consistent relationship with atopy. The group at risk of suboptimal vitamin C supply from breast milk was identified as infants whose mothers suffer from food hypersensitivity. CONCLUSION: A maternal diet rich in natural sources of vitamin C during breastfeeding could reduce the risk of atopy in high-risk infants.

Effect of functional food ingredients: vitamin E modulation of cardiovascular diseases and immune status in the elderly.

Increased accumulation of free radicals over time reduces the effectiveness of antioxidant defense mechanisms and heightens the vulnerability of older individuals to a variety of oxidative insults and associated pathologic conditions. Both nutritive and nonnutritive components of foods may slow declines in certain body functions. Ingestion of vitamin E, an antioxidant nutrient, in amounts above current recommendations may reduce the risk of cardiovascular disease, enhance immune status, and otherwise modulate important degenerative conditions associated with aging. Early adoption of proper dietary habits helps adults to maintain quality of life as they age. Increased intake of vitamin E through selection of foods with large amounts of that vitamin and daily consumption of 5-8 servings of fruit and vegetables may reduce risk for cardiovascular disease and improve immune function in later life.

Nutrition factors in relation to cellular and regulatory immune variables in a free-living elderly population.

Aging is associated with a greater susceptibility to nutrition deficiencies and to progressive senescence of the immune system. To test whether nutrition status contributes to the immunologic changes observed in elderly individuals, we examined the relationship between nutrition status and in vitro indices of immune responses in 82 healthy, free-living elderly individuals. Nutrition status was assessed by anthropometric measurements, 7 d food records, and blood concentrations of selected nutrients. Using regression analyses, we found that none of the nutrition factors was associated with cytotoxic activity of natural killer (NK) cells against the leukemic cell line K562. However, our results suggest that the dietary intakes of vitamins E and D negatively influenced the activity of interleukin 2 (IL-2) measured by a bioassay in which the CTLL cell line was used. An association may exist between particular aspects of nutrition status and regulation of immune response by IL-2. The need for further studies is emphasized.

Immune response to influenza vaccine in healthy elderly: lack of association with plasma beta-carotene, retinol, alpha-tocopherol, or zinc.

Immunity and nutritional status are compromised with age, yet the relationship between them is unclear. Immune responses and plasma micronutrient levels of 61 healthy elderly (mean 81 years) and 27 young (mean 27 years) were assessed before and after immunization with trivalent influenza vaccine (FLU). FLU-induced proliferation and IFN-gamma levels of elderly were lower than young before and after immunization. Proliferation and IFN-gamma levels increased after immunization of young, but not elderly. FLU-induced IL-6 and IL-10 levels did not change after immunization of either group. While antibody titers to all three FLU components increased after vaccination of young and elderly, post-vaccination titers of elderly were lower than young. Although plasma retinol and zinc levels of young and elderly were similar before and after vaccination, elderly had higher plasma beta-carotene and alpha-tocopherol levels at both assessments that increased after vaccination. Importantly, plasma micronutrient levels were comparable for elderly with or without intact (titers >/=40 and fourfold rise post-vaccination) antibody responses after vaccination. These results suggest that differences in these plasma micronutrients (1) are not required to observe decreased FLU responses of healthy elderly compared to young and (2) are not associated with differences in antibody responses among healthy elderly.

Vitamin E status and immune function.

Evidence from animal and human studies indicates that vitamin E plays an important role in the maintenance of the immune system. Even a marginal vitamin E deficiency impairs the immune response, while supplementation with higher than recommended dietary levels of vitamin E enhances humoral and cell-mediated immunity. The current RDA level of vitamin E prevents clinical deficiency syndrome but in some situations, especially in older subjects or in a disease state, fails to maintain optimal host defense. The immunological parameters reviewed are all sensitive to changes in the availability of vitamin E and, therefore, may reflect the vitamin E status of a given individual more accurately than conventional methods.