Immune response innate mechanisms

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. 

Thus, together these studies suggest that the oxidative burst machinery has evolved before the crown diversification of eukaryotes (Baldauf 2003) to provide marine algal lineages with natural and induced innate immunity mechanisms. These play a role similar to the HR in terrestrial plants infected by incompatible pathogens and they share important common traits with the innate immunity response of mammalian phagocytes. 

Numerous experiments have suggested that LDL oxidation generates determinants that lead to a specific immune response that, together with the innate immune response, acts as an oxLDL clearance mechanism (Fignre lA) (Horkko etal, 2000 Shaw etal, 2000). 

The recent elucidation of the immunomodulatory activities of host defense peptides is perhaps the most intriguing to the development of these molecules as therapeutics. Importantly, many peptides that have been demonstrated to be devoid of antimicrobial activity under physiological conditions have maintenance of immunomodulatory activities. That host defense peptides have also recently been demonstrated to bridge innate and adaptive immune responses and as well act as adjuvants extends their therapeutic potential beyond the resolution of infection. Recent investigations have also sought to define the cell receptors involved in the immunomodulatory activities of host defense peptides in an effort to define the mechanism of action of these molecules and further the understanding of how these molecules are able to elicit such a broad range of... 

The basal immunological mechanisms are complex but can now be analyzed with refined and more powerful laboratory methods, such as the microarray technique. With the help of this technique, additional information besides that concerning IgE and cytokine levels about the association between adaptive and innate immune response as well as other cellular responses can be gathered (6-8). 

Preventative vaccines are increasingly used during pregnancy, with the intention of protecting the newborn baby from infectious disease, such as influenza, via conferred immunity from the mother (1). To date, no causal relationships have been demonstrated for adverse effects on pregnancy with any approved vaccine. However, potential mechanisms have been suggested by which an induced immune response could interfere with prenatal development. A nonspecific disturbance of the resting balance between the innate and humoral activities of the immune system, for instance, could result in abortion (2). Otherwise, the induced antibodies may have the potential to disturb normal development due to a specific... 

The MAPK cascade in the plant s defense against bacterial pathogens is remarkably similar to the innate immune response triggered by bacterial lipopolysac-charide and mediated by the Toll-like receptors in mammals (Fig. 12-30b). Other membrane receptors use similar mechanisms to activate a MAPK cascade, ultimately activating transcription factors and turning on the genes essential to the defense response. 

Vaccination by the nasal route produces a mucosal protection using mucus, the epithelial surface, and both innate and acquired immune responses. The innate defense mechanism plays a very important role in that it influences the type of acquired immune mechanism, which mainly responds on the basis of immune memory. The ability to attain these responses is the main principle of attaining protection from infection. 

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