Utilizing multipotent and self-renewing capabilities, hematopoietic stem cells (HSCs) can maintain hematopoiesis throughout life. However, the mechanism behind such remarkable abilities remains undiscovered, at least in part because of the paucity of HSCs and the modest ex vivo expansion of HSCs in media that contain poorly defined albumin supplements such as bovine serum albumin. Here, we describe a simple platform for the expansion of functional mouse HSCs ex vivo for >1 month under fully defined albumin-free conditions. The culture system affords 236- to 899-fold expansion over the course of a month and is also amenable to clonal analysis of HSC heterogeneity. The large numbers of expanded HSCs enable HSC transplantation into nonconditioned recipients, which is otherwise not routinely feasible because of the large numbers of HSCs required. This protocol therefore provides a powerful approach with which to interrogate HSC self-renewal and lineage commitment and, more broadly, to study and characterize the hematopoietic and immune systems.

利用多能和自我更新的能力，造血干细胞 (HSC) 可以在整个生命过程中维持造血功能。然而，这种显着能力背后的机制仍未被发现，至少部分是因为 HSC 的缺乏和 HSC 在含有定义不明确的白蛋白补充剂（如牛血清白蛋白）的培养基中适度的离体扩增。在这里，我们描述了一个简单的平台，用于在完全定义的无白蛋白条件下将功能性小鼠 HSC 体外扩增 > 1 个月。该培养系统在一个月内可实现 236 至 899 倍的扩增，并且还适用于 HSC 异质性的克隆分析。大量扩增的 HSC 能够将 HSC 移植到非条件性受体中，否则由于需要大量 HSC，这在常规情况下是不可行的。