Immune system cellular aspects

Several comprehensive reviews of the immunotoxicity of TCDD have been published.13 Therefore, the goal of this chapter is to highlight the most recent developments in the field, with particular attention given to studies that provide new insight into the possible cellular and molecular mechanisms of PHAH immunotoxicity. New data that address three less-studied aspects of TCDD immunotoxicity will also be reviewed, including altered innate responses, toxicity to the developing immune system, and deregulation of anamnestic immune responses. 

The majority of patients with Burkitt s lymphoma showed an intact delayed hypersensitivity response to DCNB and lymphocyte transformation to phytohemagglutinin was also normal in the majority of patients (Z3). Fass et al. (F2) reported that 12 patients with Burkitt s lymphoma when tested with autologous tumor extracts showed measurable cellular responses of the host against his own tumor. In contrast to patients with Burkitt s lymphoma who have impaired antibody production but normal cellular immunity, patients with other forms of neoplasia of the reticuloendothelial system frequently have impairment of both the humoral and cellular aspects of immunity. 

Bone marrow suppression that affects white blood cells more than platelets is the major dose-limiting toxicity. Maximal suppression of blood cell count occurs 10 to 14 days after drug administration recovery is generally seen 21 to 28 days after injection. Cyclophosphamide reduces the number of circulating lymphocytes and impairs the function of both humoral and cellular (i.e., B and T cell) aspects of the immune system. Chronic therapy increases the risk of infections. Nausea may occur a few hours after administration. Alopecia is more common than with other mustards. 

Viruses use a large variety of mechanisms to evade cellular defense mechanisms. Almost every aspect of the innate or adaptive immune systems provides some opportunity for evasion.)) The rapid... 

The effect of stress on the endocrine and immune systems depends upon its duration and severity. Following acute stress, the rise in ACTH in response to the release of corticotrophin releasing factor (CRF) from the hypothalamus results in a rise in the synthesis and release of cortisol from the adrenals. The increase in the plasma cortisol concentration results in a temporary suppression of many aspects of cellular immunity. Due to the operation of an inhibitory feedback mechanism, stimulation of the central glucocorticoid receptors in the hypothalamus and pituitary causes a decrease in the further release of CRF, thereby decreasing the further... 

The potential association between the immune system and mood disorders has become a major topic of interest in biological psychiatry in the past decade. In general, three immune measures have been examined, namely white blood cell counts, functional measures of cellular immunity such as natural killer cell activity and immune cell markers as exemplified by human lymphoctye antigen (HLA). The cumulative data from these studies suggests that depressed patients have a decreased number of lymphocytes, reduced mitogen-induced lymphocyte proliferation and a reduction in the number of natural killer cells. However, this does not apply to all depressed patients. Furthermore, not all aspects of immune function... 

Methods for assessing or modeling of the responses of the human immune system to vaccines are critical components of any effort to understand the relationship between immunogenicity and either a positive or a negative outcome of vaccination. Decades of research have yielded many useful in vitro methods that enable the isolation and molecular dissection of selected components (modulators or cell types) of an immune system, whether mouse or human. While of hmited scope biologically, these systems have elucidated the modulators and cell types responsible for certain facets of humoral or cellular immunity. These systems have also been employed to define the roles that modulators and specific cell types play in particular aspects of an immune response. Missing, until recently, was an in vivo setting in which to study the human immune system. 

There are two important aspects to the immunity process those that operate on the cellular level and those that operate on the molecular level. In addition, we have to look at whether the immune system is acquired or whether it is always present. We shall discuss these two aspects in turn. 

The focus of this review was to look at the position of natural products in antifungal research and role of coumarins in this respect. In addition, we tried to consider other aspects of coumarin compoimds with major bioactivities as well. Natural products have served as an important source of drug for centuries, as about half of the pharmaceuticals in today s market are derived from natural products [322] In addition, they have had a significant role in identifying new biomedical cellular/molecular targets and act as biochemical probes, therefore, more attention should be paid to this field of research by scientists and pharmaceutical companies. In this article, we tried to present potentials of coumarins for such attentions. Moreover, Mother Nature has provided us with many new ideas in drug discovery itself. Combinatorial chemistry, wherein a molecular scaffold is substituted with a variety of substituents, was initiated as a close mimic of synthesis of different antibodies by the immune system [323]. 

NK cells are important constituents of the primary natural immune system. NK cell function is modulated by the surface expression of MHC molecules. Unlike T cells, NK cells form a first line of defense and kill target cells without prior sensitization. In addition, stimulatory and inhibitory receptors signal and control NK cell function. Therefore, it is plausible that herpesviruses also address this aspect of natural immunity. The status of this emerging field of research is presented in two reviews. An even more recent addition to the field is the recognition of the importance of chemokines, cytokines and their receptors. As expected from a virus which has co-speciated with the host, herpesviruses use this information and divert it to their advantage. For a virus it makes no difference whether the cell itself responds to virus infection, e.g. by apoptosis or any other type of internal cellular antiviral regulation, or whether the reaction is systemic and involves several specialized cells. It is therefore not surprising that viruses have also found principles to avoid induced cell death. 

Coconut oil has been demonstrated to have anti-inflammatory, analgesic and fever-reducing properties. This plays a good role in removal of toxins from cells. It is thought to curb inflammation of cells by improving cellular function. The cells become more efficient in removing toxins. Bruce Fife (Fife, 2013), in Coconut Cures lists fifteen toxins neutralized in part or whole by coconut oil. These include aflatoxin, E. co//endotoxin, and MSG. Thus in different aspects coconut oil supports the immune system and is an ideal food for immune suppressed individuals. 

Some aspects of multiple sclerosis are reflected in the animal model experimental autoimmune encephalomyelitis, which is induced by immunization of susceptible animals with appropriate encephalogenic proteins or peptides. In these animals, if cultured adult stem cell neurospheres are injected into the bloodstream, injected cells can find their way to damaged portions of the nervous system and improve function in mice. How the injected cells augmented the recovery process is unclear. One possibility is that cells recruited to the lesions differentiated into oligodendrocytes and generated new myelin sheaths, but this seems unlikely in the face of ongoing cellular destruction. 

Cannabinoids are able to cause different effects at the level of various systems and/or organs the most important effects occur on the central nervous system and on the cardiovascular system. In fact, they are able to affect mood, memory, motor coordination and cognition, and they increase heart rate and variate the systemic arterial pressure. Furthermore, it is well known the capability of cannabinoids to reduce intraocular pressure and to affect the respiratory and endocrine systems (L. E. Hollister, Health Aspects of Cannabis, Pharmacological Reviews, 38,1-20,1986). More recently, it was found that they suppress the cellular and humoral immune response and have antiinflammatory properties (A. W. Wirth et al.. Antiinflammatory Properties of Cannabichromene, Life Science, 26,1991-1995,1980). 

---