NK cells

Vitamin A deficiency reduces the number of circulating NK cells and impairs NK cell cytolytic activity. NK cells play a role in anti-viral and anti-tumour immunity that is not major histocompatibility complex (MHC)-restricted, and they are involved in the regulation of immune responses. In experimental animal models, vitamin A deficiency reduced the number of NK cells in the spleen (Nauss and Newberne, 1985 Bowman et al., 1990) and peripheral blood (Zhao et al., 1994). The cytolytic activity of...

Suggestive evidence of oral tolerance in humans

The concept of oral tolerance is mainly based on feeding experiments in rodents and has a long history (Brandtzaeg, 1996a). The understanding of this mucosally-induced down-regulatory or suppressive phenomenon has been hampered by an overwhelming mechanistic complexity. Identifiable experimental variables include genetics, age, dose and timing of post-natal feeding, anti-genic structure and composition of fed protein, epithelial barrier integrity and the degree of concurrent local immune...

References

Alcantara, O., Javors, M. and Boldt, D.H. (1991) Induction of protein kinase C mRNA in cultured lymphoblastoid T-cell by iron-transferrin but not soluble iron. Blood 77, 1290-1297. Alcantara, O., Obeid, L., Hannun, Y., Ponka, P and Boldt, D.H. (1994) Regulation of protein kinase C (PKC) by iron effect of different iron compounds on PKC-beta and PKC-alpha expression and role of the 5' flanking region of the PKC-beta gene in the response to ferric transferrin. Blood 84, 3510-3517. Bagchi, K.,...

Hierarchy of Selenium Supply in Selenium Deficiency

When Se intake is limited there is a clear hierarchy of Se supply, both to different tissues and to different selenoenzymes within a tissue. Thus, it appears that regulatory mechanisms exist, which ensure that, in Se deficiency, Se levels are maintained in certain priority organs and selenoproteins. Se is well retained by brain, endocrine and reproductive organs, indicating the relative importance of the trace element for the biological functions of these organs. In contrast, Se is lost rapidly...

Critical role of breastfeeding

Immune Componeent Breastfeeding

When much of the transferred maternal IgG has been catabolized around 2 months of age, the infant becomes still more dependent on antibodies from breast milk for specific humoral immunity. At least 90 of the pathogens attacking humans use the mucosae as portals of entry mucosal infections are in fact a major killer of children below the age of 5 years, being responsible for more than 14 million deaths of children annually in developing countries. Diarrhoeal disease alone claims a toll of 5...

Introduction and Overview

Nutrients are primary factors in the regulation of the human immune response. Both macronutrients and micronutrients derived from the diet affect immune-system function through actions at several levels in the gastrointestinal tract, thymus, spleen, regional lymph nodes and immune cells of the circulating blood (Chandra, 1997 Cunningham-Rundles and Lin, 1998 Wallace et al., 2000 Cunningham-Rundles, 2001). Effects at one level may be opposed or modified at another level. Thus, the development of...

Immunoregulation and Stimulation by Probiotics Laboratory and Clinical Studies

Although the primary site of immunological signalling is at the gut mucosal interface, there is evidence that the immunomodulatory effects of probiotics can be expressed systemically. Typically, this is manifested by changes in leucocyte or humoral function, which can be assessed by ex vivo assays. To date, several compartments of the immune system have been identified as affected by probiotic delivery, including lymphocyte function proliferation, cytokine secretion and cellular cytotoxicity...

Changes in eicosanoid synthesis

Anti Tumour Neutrophil

A key link between fatty acids, inflammation and immune function is a group of bioactive mediators termed eicosanoids prostaglandins, leucotrienes, thromboxanes , which are synthesized from 20-carbon PUFAs Fig. 4.4 . The two Fig. 4.4. Outline of synthesis of eicosanoids from 20-carbon n-6 and n-3 polyunsaturated fatty acids. COX, cyclo-oxygenase DGLA, dihomo-7-linolenic acid EPA, eicosapentaenoic acid HETE, hydroxyeicosatetraenoic acid LOX, lipoxygenase LT, leucotriene PG, prostaglandin TX,...

Mechanism of the Effect of Oxidants and Antioxidants on Inflammation and Immune Function

Otz Glutathione

There is a growing body of evidence that antioxidants suppress inflammatory components of the response to infection and trauma and enhance components related to cell-mediated immunity see Hughes, Chapter 9, Prasad, Chapter 10, and McKenzie et al., Chapter 12, this volume . The reverse situation applies when antioxidant defences become depleted. The oxidant molecules produced by the immune system to kill invading organisms may activate at least two important families of proteins that are...

Measles

Vitamin A supplementation reduces the morbidity and mortality from acute measles in infants and children in developing countries. Children with low circulating vitamin A concentrations had higher mortality from measles in a study from Kinshasa, Zaire Markowitz et al., 1989 . An early clinical trial from London showed that vitamin A supplementation could reduce mortality in children with acute measles Ellison, 1932 . Clinical trials showed that high-dose vitamin A reduces morbidity and mortality...

The Cell Biology of Zinc with Relevance to the Immune System

Treatment of lymphocytes with mitogens results in a fairly rapid increase in cellular Zn see Zalewski, 1996 Shankar and Prasad, 1998 Prasad, 2000a . These findings are consistent with studies indicating a requirement for Zn during the mid to late G1 phase of the cell cycle in promotion of thymidine kinase expression Chesters et al., 1993 and in another less well-defined step involved in cell transition to S phase. Activated lymphocytes take up Zn via multiple mechanisms, including receptors for...

Taurine and Immune Function

Taurine, along with sulphate, can be regarded as a biochemical end-product of cysteine metabolism. However, it is apparent that taurine also plays a role in immune function. It is the most abundant free nitrogenous compound often incorrectly classified as an amino acid in cells. It is a membrane stabilizer and regulates calcium flux, thereby controlling cell stability. It has been shown to possess antioxidant properties and to regulate the release of pro-inflammatory cytokines in hamsters, rats...

Role of Glutamine in the Pathogenesis of Type Diabetes

Since glutamine appears to act to promote lymphocyte activity, it has been proposed that increased availability of glutamine could play a role in the patho-genesis of some autoimmune conditions, such as type 1 diabetes Wu et al., 1991 . Indeed, the administration of the anti-glutamine-utilization drug acivicin delayed or stopped the progression of the disease in diabetes-prone rats Misra et al., 1996 . Addition of the glutaminase inhibitor 6-diazo-5-oxo-norleucine to macrophages before exposure...

Importance of homoeostatic immune regulation

It may seem paradoxical that mucosal disorders, such as inflammatory bowel disease IBD and coeliac disease, appear to depend, at least initially, on putative Th1-cell-driven pathogenic mechanisms Scott et al., 1997 Brandtzaeg et al., 1999d , while atopic IgE-mediated allergy originates from Th2-cell responses Brandtzaeg, 1997b Corry and Kheradmand, 1999 , which generate the essential cytokines IL-4 and IL-13 early phase as well as IL-3, IL-5 and granulocyte-macrophage colony-stimulating factor...

Endocrine effects of arginine

Elevated plasma levels of arginine have been found to correlate with increased secretion of various hormones, including prolactin and growth hormone from the pituitary, insulin, glucagon, insulin-like growth factor 1 IGF-1 and adrenal catecholamines see Barbul, 1996 . These hormones, in turn, can affect the functioning of the immune system. While the powerful secretagogue action of arginine is largely unexplained, a direct cholinergic effect, membrane depolarization by this highly cationic...

Factors affecting ThTh differentiation

CD8 T-cells are predestined to mature into cytotoxic T-cells. However, Th1 and Th2 cells develop from a common CD4 T-cell precursor. Differentiation of precursor Th-cells is determined by genetic and environmental factors influential at the time of T-cell antigen recognition. Several factors influencing Th1 Th2 polarization have been proposed and demonstrated, but the most potent factor is the local cytokine milieu present at the time of T-cell activation. The most potent cytokine promoting...

Integration and regionalization

Balt Immune Function

Lymphoid cells are located in three distinct compartments in the gut organized gut-associated lymphoid tissue GALT , the lamina propria and the surface epithelium. GALT comprises the Peyer's patches, the appendix and numerous solitary lymphoid follicles, especially in the large bowel O'Leary and Sweeney, 1986 . All these lymphoid structures are believed to represent inductive sites for intestinal immune responses Brandtzaeg et al., 1999a . The lamina propria and epithelial compartment...

Linoleic and alinolenic acids and acquired immune function

Essential fatty-acid deficiency is reported to decrease thymus and spleen weight and suppress cell-mediated immune responses and antibody production for references, see Kelley and Daudu, 1993 Calder 1998a . However, a large number of studies in rats, mice, rabbits, chickens and monkeys have reported lower mitogen-stimulated lymphocyte proliferation and antibody production following the feeding of diets rich in linoleic acid maize, sunflower or safflower oils , compared with feeding high-fat...

L Role of Iron in Immunity and Infection

Surendra Baliga2 1 Division of Hematology Oncology, Department of Pediatrics, Louisiana State University Health Sciences Center, Box T8-1, 1542 Tulane Avenue, New Orleans, LA 70112, USA 2Department of Pediatrics, College of Medicine, University of South Alabama, 2451 Fillingim Street, Mobile, AL 36617, USA Iron is the fourth most common element on earth and is one of the most studied nutrients in human health see Yip and Dallman, 1996 . Iron exists in two main forms...

Thymulin

Thymulin is a nine-peptide hormone Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn secreted by thymic epithelial cells. Zn is bound to thymulin in a 1 1 stoi-chiometry via the side-chain of asparagine and the hydroxyl groups of the two serines. The binding of Zn results in a conformational change, which produces the active form of thymulin. Thymulin binds to high-affinity receptors on T-cells and promotes T-cell maturation, cytotoxicity and interleukin IL -2 production see Shankar and Prasad, 1998 ....

The secretory antibody system and its function

Diagram Gut Lumen Lamina Propria

The remarkable magnitude of GALT as an inductive site for B-cells is documented by the fact that more than 80 of all Ig-producing blasts and plasma cells in an adult are located in the intestinal lamina propria Brandtzaeg et al., 1999a . As mentioned above, most such terminally differentiated mucosal B-cells immunocytes produce J-chain-containing dimers and some larger polymers of IgA, collectively called pIgA. These polymers as well as pentameric IgM with J chain are efficiently transported...

Glutamine Metabolism by Cells of the Immune System

Malic Enzyme

The possible fates of glutamine carbon are shown in Fig. 6.4. One possible rate-determining step in the pathway of glutamine utilization is that catalysed by the enzyme phosphate-dependent glutaminase hereafter referred to as glutaminase , which is found within mitochondria. The activity of glutaminase is high in all lym-phoid organs examined, including lymph nodes, spleen, thymus, Peyer's patches and bone marrow Ardawi and Newsholme, 1985 , and in lymphocytes Ardawi, 1988a Keast and Newsholme,...

Harsharnjit S Gill

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The Tcell receptor

Each T-cell possesses approximately 30,000 antigen-specific T-cell receptor TCR molecules on its surface, each with the same antigen specificity. Unlike B-cell immunuoglobulin molecules, TCR is always surface-bound, is not secreted and does not undergo any form of isotype switching or somatic hypermutation. The TCR Fig. 1.2 comprises two transmembrane glycoprotein chains, linked by a disulphide bond. A single a and a single p chain associate to form the majority 90 of TCRs. However, 10 of...