Phagocytic ability activity

The neutrophils (also called polymorphonuclear leucocytes, PMNs), which are the professional phagocytes of the body. They constitute >70% of the total leucocyte population, remaining in the circulatory system for less than 48 hours before migrating into the tissues, in response to a suitable stimulus, where they phagocytose material. They possess receptors forFc and activated C3 which enhance their phagocytic ability (see later in chapter). 

Steroids also alter important functional activities of lymphocytes and monocytes. This effect is mainly on T lymphocytes and is at least partly due to a decrease in IL-2 production. Other proinflammatory cytokines such as IL-1 and IL-6 are also down regulated (Barnes, 2001 Krensky et al., 2005). The effect on B lymphocytes is less prominent. Steroids also profoundly impair the function of monocytes/macrophages by significantly decreasing their phagocytic ability. Glucocorticoids also increase I B expression, thereby curtailing activation of NF-kB, which increases apoptosis of activated cells (Auphan etal., 1995). 

Additional molecular mechanisms must also mediate IFN-y effects, as it promotes a marked clinical improvement in some CGD patients without enhancing phagocyte activity. IFN-y s demonstrated ability to stimulate aspects of cellular and humoral immunity (e.g. via T- and B-lymphocytes), as well as NK cell activity, is most likely responsible for these observed improvements. 

A number of cells, including cytotoxic T lymphocytes, NK cells, and mononuclear phagocytic cells, are endowed with cytotoxic abilities and thus mediate important immunosurveillance mechanisms against neoplastic cells and viral infections. In immune-compromised hosts, a correlation has been observed between low NK cell activity and morbidity [22-25] or the incidence and severity of upper respiratory tract infections [24],... 

LL-37 has been demonstrated to affect DC differentiation from monocytes. Thus, monocytes primed with LL-37 demonstrated upregulated phagocytic capacity, and when induced to differentiate to DCs exhibited increased costimulatory molecule expression, enhanced Thl-cytokine production, and improved ability to activate Thl-polarized T-cell immunity. A subsequent investigation by Kandler et working with... 

Oral administration of orotic acid to guinea-pigs can stimulate the phagocytic activity of leukocytes against injected chicken erythrocytes [185]. The sodium salt of orotic acid can also increase phagocytosis and the digestive ability of the leukocytes in the rats [186]. 

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