Military Strategies for Sustainment of Nutrition and Immune Function in the Field (1999) / Chapter Skim
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Appendix A: Overview of the Immune System and Other Host Defense Mechanisms
Appendix A: Overview of the Immune System and Other Host Defense Mechanisms
Pages 511-526
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From page 511... ...
The generalized primary forms of host defense are termed "innate," "inborn," or "nonspecific" immunity (Abbes et al., 1995; Brostoff et al., 19911. These initial defensive mechanisms guard the body by contributing protective responses that are effective against a diverse variety of threats.
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From page 512... ...
; exogenous body secretions (mucin, saliva, bronchial fluids, gastric HC1, properdin, opsonins, lysozyme, etc.~; physicochemical environments within normal tissues; normal ciliary activity; normal physiological factors (age, sex, race, circadian rhythms) ; normal microbiological flora in various locations; and even occupational and environmental factors.
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From page 513... ...
The union of a cytokine with its specific cellular receptor leads to the activation of phospholipase enzymes within the target cell wall and the subsequent release into the cell of arachidonic acid (from n-6 polyunsaturated fatty acids [PUFAs] in the plasma membrane)
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From page 514... ...
Cytokines with inhibitory actions can block the synthesis and release of other cytokines. In addition, target cells release cytokine receptors into the plasma, and these soluble free receptors can intercept and inactivate the cytokine before it reaches the target cell.
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Despite these noxious symptoms, inflammatory reactions serve to localize a disease process and prevent it from becoming generalized. Inflammatory reactions initially include dilation of local blood vessels, vascular congestion, and the binding of white blood cells to the endothelium.
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From page 516... ...
. Induction of the cascade by antibodies produces the "classic activation pathway," and initiation by endotoxins or microbial antigens produces the "alternate activation pathway." In the classic complement activation pathway, aggregated antigen-antibody complexes bind to C1 (first complement component)
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From page 517... ...
memory, the primary and secondary recognition of a specific antigen by lymphocytes: after the first lymphocytic identification of a new foreign antigen, clonal proliferation occurs, memory cells eventually survive as programmed lymphocytes that will respond to that same antigenic determinant for the indefinite future; 4. self-limitation, the waning of an immune response after initial interactions with (and generally, elimination of)
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From page 518... ...
When stimulated by an appropriate antigen, B-cells undergo clonal expansion and transformation into antibody-producing plasma cells. IgA molecules are joined by J and "secretory" pieces produced by mucosal and epithelial cells, and the resultant IDA dimers are then secreted to generate surface immunity.
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From page 519... ...
surface component of the immune system recognizes foreign antigens on body surfaces (including the respiratory and intestinal mucosa) and produces antibodies for secretion in tears and in mucosal, dermal, and intestinal fluids.
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From page 520... ...
CD8+ T-cells recognize antigen fragments associated with Class I MHC molecules on cell surfaces. Cells infected by a virus may exhibit viral peptide antigens linked to surface Class I molecules.
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From page 521... ...
Humoral Immunity Humoral immunity involves the production of antibodies against specific antigens. Like CMI, humoral immunity has both a systemic component (which produces serum antibodies IgG, IgM, and IgA)
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From page 522... ...
. After the first exposure of a B-cell to a new foreign antigen, systemic antibody production focuses predominantly on IgM, with relatively little IgG produced.
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From page 523... ...
Plasma antibodies have a multiplicity of actions that provide the interior of the body with systemic humoral immunity. Plasma IgA molecules are joined by I- and "secretory" pieces produced by mucosal and epithelial cells, and the resultant IgA dimers are then secreted to generate surface (mucosal and epithelial)
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From page 524... ...
These reactions lead to tissue destruction, as seen in autoimmune diseases; the rejection of transplanted foreign tissue; or skin diseases such as pemphigus. · Type III reactions are immune complex reactions that are also triggered by IgG or IgM and are caused by the interaction of soluble antigen-antibody complexes with complement.
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From page 525... ...
1996. Supplementation with vitamins C and E enhances cytokine production by peripheral blood mononuclear cells in healthy adults.
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