Immune effectors eosinophils

Cytokines and chemokines made by cells such as keratinocytes, macrophages and LC might be expected to recruit and activate leukocytes, which have the potential to kill schistosomula before the development of any adaptive immunity. In vitro, schistosomula have been shown to be susceptible to a wide array of immune effector mechanisms mediated by eosinophils and neutrophils (Butterworth, 1984 Capron and Capron,... 

CeU recruitment to the site of damage (monocytes that infiltrate tissues to become macrophages, neutrophils, antigen-presenting dendritic cells, lymphocytes including B- and T-ceUs (leading to an adaptive immune response), natural killer cells (an effector cell in innate immunity) and eosinophils). 

Thus, for the Hymenolepidids the data can be interpreted to fit the Th2 paradigm with the involvement of the predicted immune/ physiological effector mechanisms AB, complement, mast cells, eosinophils and goblet cells. 

The most relevant bioassays measure specific activities on immune function, either as effector or regulatory, for example, assay of cytokine IL-12 by the augmentation of the cytolytic function of natural killer cells (B9), IL-10 by the inhibition of the production of TNF-o from stimulated monocytes (B13), and IL-8 and eotaxin by the chemotaxis of neutrophils and eosinophils, respectively (C2). 

T-cells can be subdivided in polarized type I and type II cells, depending on the spectrum of cytokines which they are able to produce. Thl cells are characterized by production by of TNF and IFN-y and activate immunity based on macrophage activation and effector functions. At the other extreme of the spectrum, Th2 cells are characterized by IL-4 and IL-5 production and elicit immune responses based on the effector function of mastocytes and eosinophils. The latter cell types are typically involved in allergic inflammation. 

A detailed analysis of T cell subsets and functions over the last 20 years resulted in a better understanding of the heterogeneity of cellular immune responses, which should also be incorporated in the well-known Cell and Coombs classification. Therefore T cell-meditated type IV reactions were further subclassified into IVa-IVd reactions as proposed in Fig. 4 (Pichler 2003). This subclassification considers the distinct cytokine production by T cells and thus incorporates the well-accepted Thl/Th2 distinction of T cells. It includes the cytotoxic activity of both CD4-I- and CD8-I- T cells (IVc), and it emphasizes the participation of different effector cells such as monocytes (IVa), eosinophils (IVb), or neutrophils (IVd), which are the cells that mediate the inflammation and tissue damage. 

The expression of both FceRI and CD23 by human eosinophils enables this cell type to act in two ways in the immune response as an effector and as a regulatory... 

Although it has been shown in some experimental circumstances that IgE responses might be beneficial to the parasite and that anti-IgE treatment (86) could increase immunity, it should be stressed that most of these observations were made in the mouse, which, unlike rats and humans, does not express EceRI on effector and antigen-presenting cells (eosinophils, macrophages, and dendritic... 

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