Mast cell progenitor trafficking and maturation.

Mast cells are derived from the hematopoietic progenitors found in bone marrow and spleen. Committed mast cell progenitors are rare in bone marrow suggesting they are rapidly released into the blood where they circulate and move out into the peripheral tissues. This migration is controlled in a tissue specific manner. Basal trafficking to the intestine requires expression of α4β7 integrin and the chemokine receptor CXCR2 by the mast cell progenitors and expression of MAdCAM-1 and VCAM-1 in the intestinal endothelium; and is also controlled by dendritic cells expressing the transcriptional regulatory protein T-bet. None of these play a role in basal trafficking to the lung. With the induction of allergic inflammation in the lung, there is marked recruitment of committed mast cell progenitors to lung and these cells must express α4β7 and α4β1 integrins. Within the lung there is a requirement for expression of VCAM-1 on the endothelium that is regulated by CXCR2, also expressed on the endothelium. There is a further requirement for expression of the CCR2/CCL2 pathways for full recruitment of the mast cell progenitors to the antigen-inflamed lung.

肥大细胞来源于骨髓和脾脏中的造血祖细胞。定向的肥大细胞祖细胞在骨髓中很少见，这表明它们会迅速释放到血液中，在血液中循环并迁移到外周组织。这种迁移是以组织特异性的方式进行控制的。向肠道的基础迁移需要肥大细胞祖细胞表达α4β7整合素和趋化因子受体CXCR2，以及肠道内皮细胞表达MAdCAM - 1和VCAM - 1；并且还受表达转录调节蛋白T - bet的树突状细胞控制。这些在向肺的基础迁移中都不起作用。随着肺部过敏性炎症的诱导，大量定向的肥大细胞祖细胞被募集到肺部，并且这些细胞必须表达α4β7和α4β1整合素。在肺部，内皮细胞上需要表达VCAM - 1，它受内皮细胞上也表达的CXCR2调节。为了使肥大细胞祖细胞完全募集到抗原炎症的肺部，还需要表达CCR2/CCL2通路。