Macrophages are conveed to epitheloid cells by which cytokine ?
Ans. is 'b' i.e., IFN-y A granuloma is a focus of chronic inflammation consisting of a microscopic aggregation of macrophages that are transformed into epithelium like cells (epithelioid cells) surrounded by a Collor of mononuclear leukocytes, principally lymphocytes and occasionally plasma cells. Frequently, these epitheloid cells fuse to form giant cells in the periphery or some times in the center of granuloma. Pathogenesis of granuloma Immune granuloma (most common type of granuloma) is a type IV hypersensitivity that involved CD-4 helper T cell. On-exposure to paiculate antigen macrophages process and present this antigen to Helper T cells and also secretes IL-2. T-cells are activated on contact with this antigen and by IL-2. Activated T-cells (helper) produce IFN-y, the major cytokine of granulomatous inflammation. IFN-y has the following effects It is the most impoant activator of macrophages. It induce granuloma formation by conversion of activated macrophages into epitheliod cells and formation of giant cell. Augment the differentiation of T-cells. Finally there is formation of granuloma induced by IFN-y. Remember Foreign body (Nonimmune) granuloma consist almost entirely of epitheloid cells and multinucleated giant cells but no lymphocytes. Granulomas induced by parasites contain a large component of eosinophils. In lymphogranuloma venerum and Cat scratch disease granulomas have a characteristic central neutrophilic abscess surrounded by macrophages and other mononuclear cells.
IL-2
IFN-y
TNF-a
TGF-(3