Immune response overview

The above scientific information on rice bran phytochemicals indicates that a multitude of mechanisms are operating at the cellular level to bring about specific health effects. Several health benefits of rice bran appear to be the result of the synergistic function of the many phytochemicals, antioxidants, vitamins and minerals which operates through a specific immune response. Their role in the biochemical mechanisms at the cellular level which result in major health effects is shown in Fig. 17.1. A short overview summarizing the effect of the various phytochemicals on major health issues such as cancer, immune function, cardiovascular disease, diabetes, altered liver function and gastrointestinal and colon disease will be given below. 

Finally, in this brief overview of lymphocyte defects, mention should be made of mutations affecting major histocompatibility-complex (MHC) Class II molecules. These mutations affect a multiprotein transcription factor complex that regulates the expression of MHC Class II molecules (121). Affected patients have undetectable levels of MHC Class II antigens HLA-DP, DQ, and DR on the surface of monocytes and B cells. Lack of these antigen-presenting molecules leads to impaired immune response. Affected individuals have moderate lymphopenia with a severely reduced number of CD4+ T cells and normal or increased numbers of CD8+ T cells. Since MHC molecules in the thymic epithelium play a key role in positive and negative selection of primitive T cells, selection of competent T cells is also affected in the absence of MHC Class II antigens. 

The intestinal immune response, or more appropriately the immunophysiological response, to tapeworms can be considered in two categories (i) creation of an inhospitable environment and (ii) active humoral events aimed at destruction of the tegument, destro-bilization and scolex detachment. We provide a brief overview of the response to cestodes, with pertinent species-specific and life-cycle stage-specific events given in the following section. 

Franchimont D. Overview of the actions of glucocorticoids on the immune response a good model to characterize new pathways of immunosuppression for new treatment strategies. Ann NY Acad Sci. 2004 1024 124-137. 

The innate and adaptive branches of the immune response are both needed for optimal immune function, and the two interact extensively.18,23 The adaptive response s ability to recognize and deal with foreign pathogens likewise involves an incredibly complex interaction between various cellular and chemical (humoral) components.23 48 51 A detailed description of the intricacies of how these components work together is beyond the scope of this chapter. Many aspects of the immune response are still being investigated. An overview of key cellular and humoral elements that mediate acquired immunity is illustrated in Figure 37-1, and these elements are described briefly below. 

Clearly, the immune response is an intricate sequence of events that involves a complex interaction between a number of cellular and humoral components. The overview provided here is just a brief summary of how some of the primary components participate in mediating acquired immunity. Readers are referred to additional sources for more information on this topic.16,18,49... 

Chaplin DD. Overview of the human immune response. J Allergy Clin Immunol. 2006 117(suppl mini-primer) S430-S435. 

TCDD and structurally related compounds elicit a wide range of adverse effects. Of the many adverse responses observed both in humans and experimental animals after exposure to 2,3,7,8-TCDD, the ones that appear at the lowest dose (more sensitive) are perhaps developmental/reproductive effects, alterations in the immune response, and neoplasia. An overview of the mechanism(s) involved in these effects is presented below. Detailed mechanistic explanations are beyond the scope of this profile. Some of the information has been extracted from recent reviews on these subjects (Kerkvliet 1995 Lucier et al. 1993a Peterson et al. 1993). 

Fig. 8.1 An overview of the cells involved in the immune response both innate and adaptive components. The cells arise from a pluripotent progenitor cell within the bone marrow, with their growth and differentiation controlled by numerous growth factors. The T lymphocytes differentiate in the thymus gland.

---