Nonspecific immunity

The prophylactic stimulation of the immune system using vaccines and bacterins is time-consuming. Of even greater value would be the abiUty to activate the system to combat a disease attack already underway, or to be able to increase the response to abnormal cells and neutralize neoplasia in any organ of the body. Several compounds, some unique entities and some already in use for other purposes, have shown potential utiUty as such nonspecific immune stimulants. 

Schwarz, E. et al., Oral administration of freshly expressed juice of Echinacea purpurea herbs fail to stimulate the nonspecific immune response in healthy young men Results of a double-blind, placebo-controlled crossover study, J Immunother, 25, 413, 2002. 

Nonspecific immunity Natural killer cell activity... 

Nonspecific immunity Macrophage function—in vitro phagocytosis of fluorescent covaspheres, killing of Listeria monocytogenes or of tumor cells [basal and activated by macrophage activating factor (MAF)]. 

The following is a brief explanation of some of the indicators that may be used to trigger additional definitive testing and a description of some of the most commonly used assays to assess humoral, cell-mediated, or nonspecific immune dysfunction, which are common to most immunotoxicology test strategies. 

The immune system is divided into two defense mechanisms nonspecific, or innate, and specific, or adaptive, mechanisms that recognize and respond to foreign substances. Some of the important cellular components of nonspecific and specific immunity are described in Table 15.4. The nonspecific immune system is the first line of defense against infectious organisms. Its cellular components are the... 

Nonspecific immunity Granulocytes Degranulate to release mediators... 

Natural Killer Cell Assays. This assay is a Tier I test for nonspecific immunity in the NTP testing scheme (Luster et al., 1988) and is proposed as an additional Type I test in the draft Redbook. 

Various drugs are capable of affecting specific immune reactions. They can both increase the general resistivity of the body or its nonspecific immunity, as well as suppress the body s immune reactions. Hence controlling diseases with immunological agents means either generation of the necessary immunity in the body, or suppression of undesirable immune reactions. 

The purple coneflower Echinacea purpura, and its close relatives, E. angustifolia and E. pallida, are the source of the herb Echinacea, which is widely popular as a nonspecific immune stimulant. These perennials are native to the prairies of North America and are now widely grown garden ornamentals. The root and aerial parts of the plant are the portions used, and the preparation s potency can be verified by the transient tingling sensation produced when it is tasted. Echinacea contains alkamides, caffeic acid esters (echinacoside, cichoric acid, caftaric acid), polysaccharides (heteroxylan), and an essential oil. Some echinacea products are standardized for their echinacoside content. In the past, adulteration with American feverfew (Parthenium integri-folium) was common. Echinacea is now sold either by itself or in combination with golden seal or zinc for the treatment of colds and influenza. 

The immune system of patients with postoperative multiple organ failure is compromised, which is confirmed by the decrease of immunocompetent cells but not immunoglobulins IgA and IgM. Nonspecific immunity of these patients is also depressed. However, after extracorporeal blood purification had been performed, immune system stimulation was observed, which was higher than hemosorption specific indicators of cellular and humoral immunity. 

Endotoxicity results from the interaction of a bacterial cell envelope component (e.g., LPS or PG with a cell surface receptor constituting part of the nonspecific immune system, (i.e., a toll-like receptor on white blood cells). This results in the production of cytokines [e.g., interleukin 1 (IL-1) or tumor necrosis factor (TNF)] as part of an intracellular enzyme cascade which can cause severe tissue injury. Bioassays or immunoassays can be used to detect such reactions respectively. As noted above the most widely used bioassay is the LAL assay. A lysate of amoebo-cytes of the horseshoe crab (Limulus) contains an enzymatic clotting cascade which is activated by extremely low levels of LPS (nanogram levels or lower). There are variants of this assay that can detect PG, but they are not as widely used. As noted above, other bioassays employ cultured cell lines that respond to LPS or PG, respectively. Unfortunately bioassays are highly amenable to false positives (from the presence of cross-reactive substances) or false negatives from inhibition (by contaminants present in the sample) [10]. A detailed discussion of these assays is beyond the scope of this chapter and has been reviewed elsewhere [1]. 

Innate or nonspecific immunity has probably developed during evolution and includes anatomical barriers such as the skin, cilia in the lungs, and bronchial tubes, as well as the presence of specific components in specialized tissues that combat invasion. 

This is a general protection that is also termed natural immunity that is present at birth in all individuals. A species is armed with innate immunity that provides an individual the basic resistance to disease. This is also called nonspecific immunity... 

PHA) Allogeneic mixed leukocyte response (MLR) Nonspecific immunity Natural killer (NK) cell activity... 

Nonspecific immunity Macrophage phagocytosis, bactericidal/tumoricidal activity)... 

The suppression of the immune system has also been demonstrated in a study in which rats were fed dietary levels of 0.025, 0.25, and 2.5 mg/kg/day bis(tributyltin)oxide for 15 months (Wester et al. 1987). The specific results were similar to findings in the intermediate-duration studies. Based on the reduction of both cellular immune responses and nonspecific immunity, a NOAEL of 0.5 tin/kg/day is suggested by the authors. 

Erickson, K.L. 1998. Dietary fat, breast cancer, and nonspecific immunity. NutrRev 56(1) Part II S99-S104. 

Sun, L., Currier, N., and Miller, S. 1999. The American Coneflower a prophylactic role involving nonspecific immunity. J. Ahem. Complement. Med. 5, 437-446. 

Our knowledge about nonspecific immunity and human nutrition, including the mechanisms of food digestion and absorption, remains extremely poor. Viruses and microorganisms that can be consumed with food, the properties of their surfaces and... 

Cellular immunity recognition and neutralization of foreign cells, pathogenic organisms, and abnormal host cells through a mechanism that is typically triggered by antibody but, once activated, does not involve antibody also termed nonspecific immunity... 

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