Effects of vitamin B6 deficiency on thymic epithelial cells and T lymphocyte differentiation.
Dietary vitamin B6 (pyridoxine) deficiency in young Lewis rats results in a reduction of T lymphocyte numbers and defects of cellular immunocompetence. In vitro studies of thymic epithelial (TE) cells, responsible for inducing T lymphocyte differentiation, revealed that maintenance on a vitamin B6 deficient diet for 2 weeks resulted in a severe defect in TE cell function. When the deficient animals were returned to a normal diet, TE cell function was restored. Exposure of lymphoid precursors from neonatally thymectomized or vitamin B6-deficient donors to normal TE monolayers resulted in their conversion to functional T lymphocytes, as measured by their response in MLR and to mitogens. However, TE monolayers from vitamin B6-deficient animals were unable to effect such a maturation of T lymphocytes. Therefore, it is suggested that the defect in cellular immunocompetence following this dietary deficiency is due, at least in part, to the inability of TE cells to effect the differentiation of T lymphocyte precursors to functional T lymphocytes. The dietary deficiency does not, however, impair lymphoid precursors, which can be stimulated to further differentiation by exposure to normal TE cell monolayers.
D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D003208:Concanavalin A / Q000494:pharmacology; D004848:Epithelium; D037102:Lectins / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D013601:T-Lymphocytes / Q000166:cytology*; D013934:Thymectomy; D013950:Thymus Gland / Q000166:cytology* / Q000473:pathology; D026681:Vitamin B 6 Deficiency / Q000276:immunology*
D037102:Lectins; D003208:Concanavalin A