Mucosa immune system

Explain how antifolates like methotrexate selectively kill cancer cells. Why do cancer patients lose their hair, intestinal mucosa, cells of the immune system, and so forth when treated with antifolates ... 

Once Salmonella invade the intestinal barrier, the bacteria encounter host immune cells such as neutrophils, lymphocytes and macrophages, which engulf the bacteria (Fields et al., 1986 McCormick et al., 1993) (Fig. 5.1). Salmonella serotypes capable of causing gastroenteritis are killed by host macrophages, and effectively cleared by the immune system. Invasion of M cells and intestinal epithelial cells induces a pro-inflammatory response in the intestinal mucosa (Fig. 5.1a). A combination of inflammatory cytokine production, neutrophil infiltration and fluid and electrolyte secretion by the epithelium results in the diarrhea associated with gastrointestinal enteritis (Fig. 5.1a). 

In genetically susceptible individuals, ingestion of cereal prolamins from wheat, barley, rye, and possibly oats initiates an inflammatory disorder during which the small intestinal mucosa is damaged. This process is accompanied by malabsorption, activation of the intestinal immune system, and... 

Following absorption from the intestinal mucosa, gluten peptides stimulate intestinal T lymphocytes to promote antibody production and release of inflammatory mediators. Stimulation of lymphocytes by gluten is seen as main step in the chain of pathogenetic events in CD and is, therefore, of central interest. Other effects of gluten peptides on intestinal epithelial cells [57, 58] and other cells [59-62] which do not seem to be directly related with activity intestinal immune system ( direct toxicity of gluten peptides) and induction of innate immune responses (for review see [63, 64]) will not be discussed here. 

Q10 Maria appears to be suffering from pernicious anaemia, which is due to failure of B12 absorption. In her case the underlying problem may be her rheumatoid arthritis, a chronic autoimmune, inflammatory condition. In autoimmune diseases the immune system attacks and damages normal tissues, including both joints and the stomach mucosa, which produces the intrinsic factor needed for Bi2 absorption. 

Allergenic effects. A number of secondary metabolites influence the immune system of animals, such as coumarins, furanocoumarins, hypericin, and helenalin. Common to these compounds is a strong allergenic effect on those parts of the skin or mucosa that have come into contact with the compounds (4,17,312). Activation or repression of the immune response is certainly a target that was selected during evolution as an antiherbivore strategy. The function of alkaloids in this context is hardly known. 

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