Immune system defense

Human natural killer (NK) lymphocytes are vital to immune system defense against viral infection. They are also crucial in protecting against primary tumor formation. In vitro exposures to low levels of two organotin pesticides, tributyltin (4.76) and triphenyltin (4.19), and two carbamate pesticides, maneb (0.62) and ziram (1.23), produced significant loss of cytotoxic function of NK cells after 6 days of exposure. The toxicities of the pesticides also increased very significantly with exposure durations J51 It should be noted that exposure to ziram can come from other sources. It is used as an additive in rubber products such as latex gloves. 

Just as medieval defenders used their weapons and the castle walls to defend their city, the immune system constantly battles against foreign invaders such as viruses, bacteria, and parasites to defend the organism. Antibody molecules provide a key element in the immune systems defensive arsenal. For example, specific antibodies can bind to molecules on the surfaces of viruses and prevent the viruses from infecting cells. Above right, an antibody binds to one subunit on hemagglutinin from the surface of influenza virus. [(Left) The Granger Collection.]... 

Unlike E. coli DNA polymerases, there is no 30 to 50 exonuclease proofreading activity in the E. coli RNA polymerase and, therefore, the error rate is relatively higher (-10-410-5). Since RNA represents only a transient copy of DNA, and is not inherited through the germ line, this error frequency is tolerable. As discussed in Chapter 30, viral RNA polymerases and another enzyme, reverse transcriptase, which also lacks proofreading activity, have error frequencies in the same range as the bacterial RNA polymerase. This mutation rate is most likely beneficial to some viruses because it results in frequent alterations in viral protein sequences and thus allows the virus to escape immune-system defenses in the host (Chapter 30). 

The immune system in vertebrates provides a defense mechanism against foreign parasites such as viruses and bacteria. Three main properties are essential to its successful operation specific recognition of foreign molecules, the ability to destroy the foreign parasite, and a memory mechanism that allows a more rapid response to a second infection by the same microorganism. 

NF-kB regulates both innate and adaptive immune responses ( immune defense) [2]. Understanding the function of NF-kB in the development, maintenance, and activation of cells from the immune system (including hematopoietic cells, macrophages, dendritic cells, B and T lymphocytes) has greatly benefited from the analysis of knockout mice in which individual NF-kB family members were defective. 

Imidazoline Receptor Immediate Early Genes Immune Complexes Immune Defense Immune System Immunity... 

A wide diversity of herbal remedies have purported abilities to stimulate defense functions. Complexes of carbohydrate and lignin, which are present in some herbs, modulate enteric immune functions (Kiyohara et al, 2000), and the changes in cytokine secretion (Matsumoto and Yamada, 2000) can trigger systemic responses. The polysaccharides present in other herbal medicines augment production of immunoglobulin (Ig) A by the Peyer s patches in the small intestine (Sakushima et al, 1997 Yu et al, 1998). The responses of the enteric immune system to lectins are variable (Pusztai 1993), and can elicit systemic responses (Lavelle et al, 2000). Other phytochemicals provide protection by inducing detoxification pathways in mucosal cells (Williamson et al, 1998). 

The mammalian immune system protects the body from infection by many complex strategies. The most vigorous defense is performed by white blood cells known as granulocytes. These cells consume oxygen in response to microbial infections. This oxidative process, called the respiratory burst, has recently been proven to produce stabilized hvDOchlorite antimicrobials (bredominantlv bv neutroDhils) and stabilized... 

This chapter presents specific information with regard to the effects of environmental and occupational exposure to arsenic on inflammatory processes, the immune system, and host defense. While the focus is on the in vivo and in vitro effects of arsenic on host immune responses (e.g., immunotoxicity and hypersensitivity) and their relationship to clinically observed manifestations of arsenic toxicity (e.g., inflammation and skin cancer), information on the potential mechanisms through which arsenic may exert its biological effects is also provided. 

---