Tacrolimus (FK506)

FK-506 inhibits Ca2+-dependent transcription of lymphokine genes in T cells.FK-506 (0.1 to 300 nM) concentration dependently inhibited histamine release from lung parenchymal mast cells activated by anti-IgE. FK-506 was more potent in lung mast cells than in basophils (IC50 = 1.13 +/- 0.46 nM vs 5.28 +/- 0.88 nM, p less than 0.001), whereas the maximal inhibitory effect was higher in basophils than in lung mast cells (88.4 +/- 2.5% vs 76.4 +/- 3.8%, p less than 0.01). [2]FK-506 (1 to 300 nM) concentration dependently inhibited histamine release from basophils activated by Der p I Ag, anti-IgE, or compound A23187. FK-506 was more potent than CsA when basophils were challenged with Ag (IC50 = 25.5 +/- 9.5 vs 834.3 +/- 79.8 nM, p less than 0.001), anti-IgE (IC50 = 9.4 +/- 1.7 vs 441.3 +/- 106.7 nM, p less than 0.001), and A23187 (IC50 = 4.1 +/- 0.9 vs 36.7 +/- 3.8 nM, p less than 0.001). The maximal inhibitory effect of FK-506 was higher than that caused by CsA when basophils were activated by Der p I (80.0 +/- 3.6 vs 49.5 +/- 4.7%, p less than 0.001) and anti-IgE (90.4 +/- 1.8 vs 62.3 +/- 2.9%, p less than 0.001). [3]

FK-506 (Tacrolimus) Chemical Structure

2 years -20CPowder, 2 weeks4Cin DMSO, 2 months-80Cin DMSO