Production of 1 alpha,25-dihydroxyvitamin D3 by hematopoietic cells.
Perhaps, 1 alpha,25(OH)2D3 plays a role as a co-factor in the communication between lymphocytes and macrophages. A schematic representation of that proposed interaction is shown in Figure 2. (Formula: see text). For example, macrophages encounter bacteria, stimulating these cells to begin chemotaxis, phagocytosis, and killing of the microorganisms. In addition, the cells produce interleukin-1. Both interleukin-1 and bacterial antigens in the context of the Ia antigens of the macrophages activate T lymphocytes. The T lymphocytes begin to synthesize lymphokines which can further activate macrophages. Macrophages stimulated by IFN-gamma eventually synthesize 1 alpha,25(OH)2D3. Activated lymphocyte express receptors for 1 alpha,25(OH)2D3; and their lymphokine production will decrease in the presence of 1 alpha,25(OH)2D3.
Reichel
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Department of Biochemistry, University of California, Riverside 92521.
Koeffler
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HP
Norman
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D000818:Animals; D002117:Calcitriol / Q000096:biosynthesis*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006934:Hypercalcemia / Q000209:etiology*; D008214:Lymphocytes / Q000378:metabolism*; D008223:Lymphoma / Q000150:complications / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051381:Rats; D012507:Sarcoidosis / Q000150:complications / Q000378:metabolism; D014376:Tuberculosis / Q000150:complications / Q000378:metabolism
D002117:Calcitriol