The influence of antioxidant nutrients on viral infection

N-Acetylcysteine and Its Immunomodulatory Properties in Humans and Domesticated Animals

N-acetylcysteine (NAC), an acetylated derivative of the amino acid L-cysteine, has been widely used as a mucolytic agent and antidote for acetaminophen overdose since the 1960s and the 1980s, respectively. NAC possesses antioxidant, cytoprotective, anti-inflammatory, antimicrobial, and mucolytic properties, making it a promising therapeutic agent for a wide range of diseases in both humans and domesticated animals. Oxidative stress and inflammation play a major role in the onset and progression of all these diseases. NAC's primary role is to replenish glutathione (GSH) stores, the master antioxidant in all tissues; however, it can also reduce levels of pro-inflammatory tumor necrosis factor-alpha (TNF-∝) and interleukins (IL-6 and IL-1β), inhibit the formation of microbial biofilms and destroy biofilms, and break down disulfide bonds between mucin molecules. Many experimental studies have been conducted on the use of NAC to address a wide range of pathological conditions; however, its effectiveness in clinical trials remains limited and studies often have conflicting results. The purpose of this review is to provide a concise overview of promising NAC usages for the treatment of different human and domestic animal disorders.

Mitochondria Dysfunction at the Heart of Viral Myocarditis: Mechanistic Insights and Therapeutic Implications

The myocardium/heart is the most mitochondria-rich tissue in the human body with mitochondria comprising approximately 30% of total cardiomyocyte volume. As the resident "powerhouse" of cells, mitochondria help to fuel the high energy demands of a continuously beating myocardium. It is no surprise that mitochondrial dysfunction underscores the pathogenesis of many cardiovascular ailments, including those of viral origin such as virus-induced myocarditis. Enteroviruses have been especially linked to injuries of the myocardium and its sequelae dilated cardiomyopathy for which no effective therapies currently exist. Intriguingly, recent mechanistic insights have demonstrated viral infections to directly damage mitochondria, impair the mitochondrial quality control processes of the cell, such as disrupting mitochondrial antiviral innate immune signaling, and promoting mitochondrial-dependent pathological inflammation of the infected myocardium. In this review, we briefly highlight recent insights on the virus-mitochondria crosstalk and discuss the therapeutic implications of targeting mitochondria to preserve heart function and ultimately combat viral myocarditis.

Western Dietary Pattern Antioxidant Intakes and Oxidative Stress: Importance During the SARS-CoV-2/COVID-19 Pandemic

The importance of balanced dietary habits, which include appropriate amounts of antioxidants to maintain the immune system, has become increasingly relevant during the current SARS-CoV-2/COVID-19 pandemic, because viral infections are characterized by high oxidative stress. Furthermore, the measures taken by governments to control the pandemic have led to increased anxiety, stress, and depression, which affect physical and mental health, all of which are influenced by nutritional status, diet, and lifestyle. The Mediterranean diet (MD), Atlantic diet (AD), and the Dietary Guidelines for Americans all provide the essential vitamins, minerals, and phenolic compounds needed to activate enzymatic and nonenzymatic antioxidant responses. However, viral pandemics such as the current COVID-19 crisis entail high oxidative damage caused by both the infection and the resultant social stresses within populations, which increases the probability and severity of infection. Balanced dietary patterns such as the MD and the AD are characterized by the consumption of fruit, vegetables, legumes, olive oil, and whole grains with low intakes of processed foods and red meat. For a healthy lifestyle in young adults, the MD in particular provides the required amount of antioxidants per day for vitamins D (0.3-3.8 μg), E (17.0 mg), C (137.2-269.8 mg), A (1273.3 μg), B-12 (1.5-2.0 μg), and folate (455.1-561.3 μg), the minerals Se (120.0 μg), Zn (11.0 mg), Fe (15.0-18.8 mg), and Mn (5.2-12.5 mg), and polyphenols (1171.00 mg) needed to maintain an active immune response. However, all of these diets are deficient in the recommended amount of vitamin D (20 μg/d). Therefore, vulnerable populations such as elders and obese individuals could benefit from antioxidant supplementation to improve their antioxidant response. Although evidence remains scarce, there is some indication that a healthy diet, along with supplemental antioxidant intake, is beneficial to COVID-19 patients.

Early nutritional supplementation in non-critically ill patients hospitalized for the 2019 novel coronavirus disease (COVID-19): Rationale and feasibility of a shared pragmatic protocol

OBJECTIVES

Beginning in December 2019, the 2019 novel coronavirus disease (COVID-19) has caused a pneumonia epidemic that began in Wuhan, China, and is rapidly spreading throughout the whole world. Italy is the hardest hit country after China. Considering the deleterious consequences of malnutrition, which certainly can affect patients with COVID-19, the aim of this article is to present a pragmatic protocol for early nutritional supplementation of non-critically ill patients hospitalized for COVID-19 disease. It is based on the observation that most patients present at admission with severe inflammation and anorexia leading to a drastic reduction of food intake, and that a substantial percentage develops respiratory failure requiring non-invasive ventilation or even continuous positive airway pressure.

METHODS

High-calorie dense diets in a variety of different consistencies with highly digestible foods and snacks are available for all patients. Oral supplementation of whey proteins as well as intravenous infusion of multivitamin, multimineral trace elements solutions are implemented at admission. In the presence of 25-hydroxyvitamin D deficit, cholecalciferol is promptly supplied. If nutritional risk is detected, two to three bottles of protein-calorie oral nutritional supplements (ONS) are provided. If <2 bottles/d of ONS are consumed for 2 consecutive days and/or respiratory conditions are worsening, supplemental/total parenteral nutrition is prescribed.

CONCLUSION

We are aware that our straight approach may be debatable. However, to cope with the current emergency crisis, its aim is to promptly and pragmatically implement nutritional care in patients with COVID-19, which might be overlooked despite being potentially beneficial to clinical outcomes and effective in preventing the consequences of malnutrition in this patient population.

Amelioration of oxidative stress using N-acetylcysteine in canine parvoviral enteritis

Previously, antioxidants have not been evaluated for treatment of parvoviral diarrhea in dogs. In this study, antioxidant potential of N‐acetylcysteine (NAC) in dogs infected with canine parvovirus with a nonblinded randomized clinical trial has been carried out. A total 18 parvo‐infected dogs were randomly divided into two groups: nine parvo‐infected dogs were treated with supportive treatment and nine parvo‐infected dogs were treated with NAC along with supportive treatment. Simultaneously, nine healthy dogs were kept as healthy control. In parvo‐infected dogs, marked hemoconcentration, leucopenia, neutropenia and oxidative stress were noticed compared to healthy dogs. The NAC treatment progressively improved the leukocyte, neutrophil, monocyte, and eosinophil counts over the time in parvovirus‐infected dogs compared to dogs that received only supportive treatment. In addition, NAC treatment significantly improved glutathione S‐transferase (GST) activity and decreased nitrite plus nitrate (NOx) and malondialdehyde (MDA) concentrations on day 3 and 5 compared to supportive treatment in parvo‐infected dogs. However, supportive treatment alone failed to ameliorate oxidative stress in the infected dogs till day 5. The results of this study suggest that NAC represents a potential additional treatment option that could be considered to improve the health condition and minimize the duration of hospitalization in case of canine parvoviral diarrhea.

Glucose-6-phosphate dehydrogenase--beyond the realm of red cell biology

Glucose-6-phosphate dehydrogenase (G6PD) is critical to the maintenance of NADPH pool and redox homeostasis. Conventionally, G6PD deficiency has been associated with hemolytic disorders. Most biochemical variants were identified and characterized at molecular level. Recently, a number of studies have shone light on the roles of G6PD in aspects of physiology other than erythrocytic pathophysiology. G6PD deficiency alters the redox homeostasis, and affects dysfunctional cell growth and signaling, anomalous embryonic development, and altered susceptibility to infection. The present article gives a brief review of basic science and clinical findings about G6PD, and covers the latest development in the field. Moreover, how G6PD status alters the susceptibility of the affected individuals to certain degenerative diseases is also discussed.

Methamphetamine reduces human influenza A virus replication

Methamphetamine (meth) is a highly addictive psychostimulant that is among the most widely abused illicit drugs, with an estimated over 35 million users in the world. Several lines of evidence suggest that chronic meth abuse is a major factor for increased risk of infections with human immunodeficiency virus and possibly other pathogens, due to its immunosuppressive property. Influenza A virus infections frequently cause epidemics and pandemics of respiratory diseases among human populations. However, little is known about whether meth has the ability to enhance influenza A virus replication, thus increasing severity of influenza illness in meth abusers. Herein, we investigated the effects of meth on influenza A virus replication in human lung epithelial A549 cells. The cells were exposed to meth and infected with human influenza A/WSN/33 (H1N1) virus. The viral progenies were titrated by plaque assays, and the expression of viral proteins and cellular proteins involved in interferon responses was examined by Western blotting and immunofluorescence staining. We report the first evidence that meth significantly reduces, rather than increases, virus propagation and the susceptibility to influenza infection in the human lung epithelial cell line, consistent with a decrease in viral protein synthesis. These effects were apparently not caused by meth’s effects on enhancing virus-induced interferon responses in the host cells, reducing viral biological activities, or reducing cell viability. Our results suggest that meth might not be a great risk factor for influenza A virus infection among meth abusers. Although the underlying mechanism responsible for the action of meth on attenuating virus replication requires further investigation, these findings prompt the study to examine whether other structurally similar compounds could be used as anti-influenza agents.

Proteome alterations in primary human alveolar macrophages in response to influenza A virus infection

To obtain a global picture of how alveolar macrophages respond to influenza A virus (IAV) infection, we used a quantitative proteomics method to systematically examine protein expression in the IAV-infected primary human alveolar macrophages. Of the 1214 proteins identified, 43 were significantly up-regulated and 63 significantly down-regulated at >95% confidence. The expression of an array of interferon (IFN)-induced proteins was significantly increased in the IAV-infected macrophages. The protein with the greatest expression increase was ISG15, an IFN-induced protein that has been shown to play an important role in antiviral defense. Concomitantly, quantitative real-time PCR analysis revealed that the gene expression of type I IFNs increased substantially following virus infection. Our results are consistent with the notion that type I IFNs play a vital role in the response of human alveolar macrophages to IAV infection. In addition to the IFN-mediated responses, inflammatory response, apoptosis, and redox state rebalancing appeared also to be major pathways that were affected by IAV infection. Furthermore, our data suggest that alveolar macrophages may play a crucial role in regenerating alveolar epithelium during IAV infection.

Prodrug approach for increasing cellular glutathione levels

Reduced glutathione (GSH) is the most abundant non-protein thiol in mammalian cells and the preferred substrate for several enzymes in xenobiotic metabolism and antioxidant defense. It plays an important role in many cellular processes, such as cell differentiation, proliferation and apoptosis. GSH deficiency has been observed in aging and in a wide range of pathologies, including neurodegenerative disorders and cystic fibrosis (CF), as well as in several viral infections. Use of GSH as a therapeutic agent is limited because of its unfavorable biochemical and pharmacokinetic properties. Several reports have provided evidence for the use of GSH prodrugs able to replenish intracellular GSH levels. This review discusses different strategies for increasing GSH levels by supplying reversible bioconjugates able to cross the cellular membrane more easily than GSH and to provide a source of thiols for GSH synthesis.

The requirement of reactive oxygen intermediates for lymphocytic choriomeningitis virus binding and growth

Multiple viruses induce reactive oxygen intermediate (ROI) generation during infection that plays an important role in growth. We have examined the importance of ROI during lymphocytic choriomeningitis virus (LCMV) infection of immortalized BHK-21 cells and murine peritoneal macrophages. Within 15 min of virus addition, intracellular ROI levels increased. To examine the contribution of ROI to LCMV infection, cells were pretreated with antioxidant prior to virus addition. Antioxidant treatment inhibited low and high MOI growth of virus. The requirement for ROI was greatest during the initial phase of infection, as antioxidant treatment after 6 h post infection had a weaker inhibitory effect. Furthermore, antioxidant treatment of cells inhibited virus binding, while treatment of virus stocks with N-ethyl malemide, which blocks free thiols, eliminated infectious virus. This illustrates that ROI are critical to the regulation of virus binding and growth and has important implications for understanding the infectivity of related viruses.

In vitro effects of selenium deficiency on West Nile virus replication and cytopathogenicity

Background

Selenium (Se) deficiency plays an important role in viral pathogenesis. To understand the effects of Se deficiency on West Nile virus (WNV) infection, we analyzed cytopathogenicity, apoptosis and viral replication kinetics, using a newly developed Se-deficient cell culture system.

Results

Both Vero and SK-N-SH cells grown in Se-deficient media exhibited a gradual loss of glutathione peroxidase (GPx1) activity without any significant effect on cell growth and viability. In SK-N-SH cells, Se deficiency had no effect on the expression of key antioxidant enzymes, including manganese- and copper-zinc superoxide dismutase (MnSOD and CuZnSOD), catalase and inducible nitric oxide synthase, whereas Vero cells demonstrated a significant increase in the expression of MnSOD and an overall increase in oxidative stress (OS) at day 7 post-induction of Se deficiency. At 2 days after infection with WNV, CPE and cell death were significantly higher in WNV-infected Se-deficient Vero cells, compared to WNV-infected control cells. Furthermore, WNV-induced apoptosis was significantly heightened in Se-deficient cells and was contributed by loss of mitochondrial membrane potential and increased caspase activity. However, no significant difference was found in WNV copy numbers between control, Se-adequate and Se-deficient cell cultures.

Conclusion

Overall results demonstrate that the in vitro Se-deficient model can be used to study responses of WNV to this essential nutrient. Although Se deficiency has no in vitro effect on WNV replication kinetics, adequate Se is presumably critical to protect WNV-infected cells against virus-induced cell death.

Glucose-6-phosphate dehydrogenase--from oxidative stress to cellular functions and degenerative diseases

Glucose-6-phosphate dehydrogenase (G6PD), the first and rate-limiting enzyme of the pentose phosphate pathway, is indispensable to maintenance of the cytosolic pool of NADPH and thus the cellular redox balance. The role of G6PD as an antioxidant enzyme has been recognized in erythrocytes for a long time, as its deficiency is associated with neonatal jaundice, drug- or infection-mediated hemolytic crisis, favism and, less commonly, chronic non-spherocytic hemolytic anemia. To a large extent, advances in the field were made on the pathophysiology of G6PD-deficient erythrocytes, and the molecular characterization of different G6PD variants. Not until recently did numerous studies cast light on the importance of G6PD in other aspects of the physiology of both cells and organisms. Deficiency in G6PD activity, and hence a disturbance in redox homeostasis, can lead to dysregulation of cell growth and signaling, anomalous embryonic development, altered susceptibility to viral infection as well as increased susceptibility to degenerative diseases. The present review covers recent developments in this field. Additionally, molecular characterization of G6PD variants, especially those frequently found in Taiwan and Southern China, is also addressed.

Undernutrition can affect the invading microorganism

Undernutrition or malnutrition adversely affects host defenses against many invading microorganisms, thereby increasing the severity of infection. Studies of RNA viruses (e.g., coxsackievirus B and influenzavirus) have shown that selenium or vitamin E deficiency in mice increases disease severity and results in stable genomic changes in the virus that increase virulence. Changes in H3N2 influenzavirus were predominantly in the ordinarily stable M1 matrix protein. Whether this represents selection of already-existing variants or direct effects on viral RNA is unclear. Related questions include whether undernutrition in persons who acquire infection with influenzavirus H5N1 could promote genomic changes during infection that result in greater virulence and higher case-fatality rates, and whether undernutrition could help create the multiple mutations needed to instigate human-to-human transmission. These possibilities emphasize the importance of alleviating world poverty and malnutrition. In addition, these findings suggest that the neglected area of undernutrition affecting invading microorganisms merits intensive investigation in humans and experimental models.

Noma (cancrum oris)

Noma is an opportunistic infection promoted by extreme poverty. It evolves rapidly from a gingival inflammation to grotesque orofacial gangrene. It occurs worldwide, but is most common in sub-Saharan Africa. The peak incidence of acute noma is at ages 1-4 years, coinciding with the period of linear growth retardation in deprived children. Noma is a scourge in communities with poor environmental sanitation. It results from complex interactions between malnutrition, infections, and compromised immunity. Diseases that commonly precede noma include measles, malaria, severe diarrhoea, and necrotising ulcerative gingivitis. The acute stage responds readily to antibiotic treatment. The sequelae after healing include variable functional and aesthetic impairments, which require reconstructive surgery. Noma can be prevented through promotion of national awareness of the disease, poverty reduction, improved nutrition, promotion of exclusive breastfeeding in the first 3-6 months of life, optimum prenatal care, and timely immunisations against the common childhood diseases.

The Relevance of Selenium to Immunity, Cancer, and Infectious/Inflammatory Diseases

Selenium is an essential trace element involved in several key metabolic activities via selenoproteins, enzymes that are essential to protect against oxidative damage and to regulate immune function. Selenium also may have other health benefits unrelated to its enzymatic functions. It may provide important health benefits to people whose oxidative stress loads are high, such as those with inflammatory or infectious diseases like rheumatoid arthritis or human immunodeficiency virus/acquired immunodeficiency syndrome, or who are at high risk for cancers, particularly prostate cancer. Some studies have generated compelling evidence that selenium is beneficial, either alone or in conjunction with other micronutrients. Additional data from large clinical trials that provide the highest level of evidence will be key to determining the benefits accrued at various selenium intake levels. When the strength of the evidence becomes sufficient, clinical health professionals will need to use dietary and clinical assessment methods to ensure that people at increased risk for cancer or inflammatory and infectious diseases can be appropriately advised about selenium intake.

Impairment of conjunctival glutathione secretion and ion transport by oxidative stress in an adenovirus type 5 ocular infection model of pigmented rabbits

Conjunctival epithelial cells of pigmented rabbits secrete reduced glutathione (GSH) into the apical (mucosal) fluid. The aim of the current study was to determine the effect of oxidative stress resulting from viral infection and that of GSH supplementation on redox status, GSH, and ion transport in freshly excised conjunctival tissues and epithelial cell layers in primary culture (RCEC) of adenovirus type 5 (Ad5)-infected rabbits. Lipid peroxidation (LPO) products, nitric oxide (NO), and expression of nitric oxide synthase (NOS2) were quantitated as a function of time after viral inoculation. Unidirectional fluxes of [3H]GSH and changes in short-circuit current (Isc) from mucosal supplementation of Ad5-inoculated conjunctival tissues with GSH and glutathione monoethyl ester (GSH-MEE) were also measured. Ad5 inoculation significantly decreased conjunctival GSH level by 19, 45, 48, and 50% at 8, 24, 48, and 72 h postinfection, respectively. LPO product and NO levels increased significantly (2- and 100-fold, respectively) above that of uninfected controls on Day 3 post-Ad5 inoculation, and co-treatment with GSH-MEE and tocopherol succinate abolished this effect. NO levels showed a progressive increase post-Ad5 inoculation, reaching 0.22 +/- 0.06, 8.12 +/- 0.91, and 2.05 +/- 0.65 microM on Days 1, 3, and 5, respectively, and the highest level was observed on the day of maximal viral replication (Day 3). A very significant induction of the expression of NOS2 on Days 1, 3, and 5 post-Ad5 inoculation was observed. Uninfected control conjunctival tissues displayed a net serosal-to-mucosal GSH flux (Jsm), where the mucosal-to-serosal flux (Jms) was approximately 14 pmol h(-1) cm(-2) and the Jsm was approximately 22 pmol h(-1) cm(-2). In Ad5-inoculated rabbits similar GSH flux was observed in both the sm and ms directions, and the net GSH flux was negligible. Isc and potential difference (PD) across conjunctival tissues of Ad5-inoculated rabbits decreased by > or = 50% compared with control, while the transepithelial electrical resistance (TEER) remained unchanged. Mucosal, but not serosal, superfusion of GSH or GSH-MEE in Ad5-inoculated conjunctival tissues increased the Isc by up to 40% in approximately 100 min. Our results show that net secretion of GSH across rabbit conjunctiva is totally blocked after Ad5 inoculation and active ion transport rate decreased by approximately 50%. Decreased net GSH secretion into mucosal fluid after Ad5 infection may have resulted from a decreased intracellular GSH pool due to oxyradical-induced changes in redox status and lower active ion transport. Mucosal treatment of Ad5-infected conjunctival tissues with pharmacological levels of GSH appears to transstimulate mucosal GSH secretion and restore active ion transport activity, suggesting a potentially useful therapeutic regimen for ocular infections.

Vitamin E as an antioxidant of the lung: mechanisms of vitamin E delivery to alveolar type II cells

Oxidants play an important role in the development of acute and chronic lung injuries. Alveolar surfactant is the first target of air-borne oxidants. Surfactant contains, besides dipalmitoyl phosphatidylcholine, cholesterol and polyunsaturated phospholipids that play an important functional role. Therefore, vitamin E could be important for protecting surfactant lipids against oxidation and subsequent lung injury. Alveolar type II cells play a central role in synthesis and secretion of surfactant lipids and also supplement the surfactant with vitamin E during intracellular assembly. High density lipoprotein (HDL) is the primary source of vitamin E for type II cells. The uptake of vitamin E by specific lipid transfer is mediated by at least three HDL-specific receptors (scavenger receptor BI, membrane dipeptidase, and HDL-binding protein-2). In addition, cubilin and megalin mediate in a cooperative manner HDL-holoparticle uptake by alveolar type II cells. A temporary vitamin E deficiency induces a reversible change of the expression of pro- and antiinflammatory markers and of markers defining apoptosis, and reduces surfactant lipid synthesis in alveolar type II cells. These metabolic changes of type II cells may prime the lung to develop clinically manifest injury in response to an additional insult, e.g., hyperoxia.

Oro-facial gangrene (noma/cancrum oris): pathogenetic mechanisms

Cancrum oris (Noma) is a devastating infectious disease which destroys the soft and hard tissues of the oral and para-oral structures. The dehumanizing oro-facial gangrenous lesion affects predominantly children ages 2 to 16 years, particularly in sub-Saharan Africa, where the estimated frequency in some communities varies from 1 to 7 cases per 1000 population. The risk factors are poverty, malnutrition, poor oral hygiene, residential proximity to livestock in unsanitary environments, and infectious diseases, particularly measles and those due to the herpesviridae. Infections and malnutrition impair the immune system, and this is the common denominator for the occurrence of noma. Acute necrotizing gingivitis (ANG) and oral herpetic ulcers are considered the antecedent lesions, and ongoing studies suggest that the rapid progression of these precursor lesions to noma requires infection by a consortium of micro-organisms, with Fusobacterium necrophorum (Fn) and Prevotella intermedia (Pi) as the suspected key players. Additional to production of a growth-stimulating factor for Pi, Fn displays a classic endotoxin, a dermonecrotic toxin, a cytoplasmic toxin, and a hemolysin. Without appropriate treatment, the mortality rate from noma is 70-90%. Survivors suffer the two-fold afflictions of oro-facial mutilation and functional impairment, which require a time-consuming, financially prohibitive surgical reconstruction.

A review of latest research findings on the health promotion properties of tea

Important progress has been made in the past five years concerning the effects of green and black tea on health. Experimentation with new accurate tools provide useful information about the metabolism of tea components in the body, their mode of action as antioxidants at the cellular level and their protective role in the development of cancer, cardiovascular disease and other pathologies. The use of tea components as nutraceuticals and functional foods are also discussed.

Immunological dysregulation of lung cells in response to vitamin E deficiency

Vitamin E supplementation exhibits anti-inflammatory properties. In the lung, the beneficial effects of vitamin E supplementation on inflammation and infections are well documented, but potential consequences of alimentary vitamin E deficiency to the immunological status of lung cells are not known. It is unclear if temporary vitamin E deficiency exhibits deleterious consequences or can be compensated for by other cellular antioxidants. To address this question, the alimentary vitamin E supply to rats was modified. We then investigated the effects on major histocompatibility molecule (MHC) class II, cell adhesion molecules, interleukin (IL)10, tumor necrosis factor (TNF)alpha in various lung cells. The constitutive expression of MHC class II, intercellular adhesion molecule (ICAM)-1, L-selectin, alpha5-integrin, and CD 166, was demonstrated by flow cytometry on type II pneumocytes, alveolar macrophages, and on co-isolated lymphocytes. Vitamin E depletion increased ICAM-1 and CD166 on type II cells and macrophages, whereas the expression of L-selectin increased only on macrophages. Furthermore, the vitamin E depletion increased the cellular content and secretion of IL10 in type II cells, but decreased the content and secretion of TNFalpha. Vitamin E depletion decreased the cellular vitamin E content, but did not change the activity of antioxidant enzymes (catalase, superoxide dismutase) and the glutathion (GSH)/oxidized glutathion (GSSG) ratio in alveolar type II cells. The shift of protein kinase C (PKC) from the cytosol to membranes indicates that a PKC-dependent signaling pathway may be involved in the change of the immunological status of type II cells. All these effects were reversed by vitamin E repletion. In summary, these results are clearly compatible with the view that a temporary vitamin E deficiency induces a reversible immunological dysregulation in alveolar type II cells and lung macrophages. This deficiency might predispose the lung to develop acute or chronic inflammation.

The selenium-coxsackievirus connection: chronicle of a collaboration

This review provides a historical account of a collaboration established between a nutritionist and a virologist to investigate the interrelationship of host nutritional status and viral virulence. The parties to this collaboration consider themselves specialists in the fields of antioxidant nutrition and viral immunology, respectively. The advantages of such talent pooling are discussed (rapid startup, well-focused experimentation, ability to visualize the "big picture"), as are some of the disadvantages (limited common scientific vocabulary, proper apportioning of credit, lack of institutional infrastructure to house such efforts). The common perception that some of the most exciting science occurs when the advancing edges of two disparate disciplines intersect is borne out by this project because host nutriture was shown for the first time to influence the genetic make-up of an invading viral pathogen. Encouragement of joint cooperative ventures should have a high priority as demanded by increasingly difficult scientific problems and as desired by scientists themselves who wish to see their research progress more quickly.

Effects of dietary antioxidants on the immune function of middle-aged adults

The immune system is highly reliant on accurate cell-cell communication for optimal function, and any damage to the signalling systems involved will result in an impaired immune responsiveness. Oxidant-mediated tissue injury is a particular hazard to the immune system, since phagocytic cells produce reactive oxygen species as part of the body's defence against infection. Adequate amounts of neutralizing antioxidants are required, therefore, to prevent damage to the immune cells themselves. Many antioxidants can be obtained directly from the diet (e.g. ascorbic acid, alpha-tocopherol, carotenoids and polyphenolic flavonoids) or require micronutrients as integral components (e.g. Se in the metalloenzyme glutathione peroxidase (EC 1.11.1.9)). Numerous epidemiological studies have found strong associations between diets rich in antioxidant nutrients and a reduced incidence of cancer, and it has been suggested that a boost to the body's immune system by antioxidants might, at least in part, account for this. Although more striking effects have been observed in the elderly, there is also evidence that antioxidant nutrients can modify cell-mediated immune responses in younger individuals. Indeed, it might be essential to have an adequate intake of antioxidant nutrients from an early age in order to help prevent the development of, or at least delay the onset of, several degenerative disorders. The present paper will review the effects of specific nutrients on immune function in young to middle-aged human subjects, focusing on the antioxidant vitamins C and E, and on Se. A further review, dealing more specifically with the effects of carotenoids on human immune function, will be presented at a forthcoming meeting of the Nutrition Society.