Scientists in the US have recreated the bone marrow environment to study how immune system cells interact. 

Nicholas Kotov and colleagues at the University of Michigan, Ann Arbor, used a poly(acrylamide) hydrogel, with an inverted colloidal crystal (ICC) structure, as a scaffold on which to grow cells. ICCs contain a regularly spaced network of pores that the researchers say resembles structures found in bone marrow and the thymus gland, which both produce infection-fighting white blood cells.

Kotov's team modified the surface of the ICC so that cells produced by the thymus, called thymic epithelial cells, would stick to it, while cells produced by bone marrow, called monocytes, would not.  This allowed the researchers to look at the movement of the monocytes and how they interact with the thymus cells.

By understanding the signalling processes of these cells, the researchers hope to gain a greater understanding of how stem cells can be used to grow immune system cells. Stem cells can develop into any type of cell, in a process called differentiation. The way that these cells develop depends on how they interact with each other.  Previously, interactions between cells of a single type had been investigated on ICC scaffolds, but Kotov sought to find out how different cell types would interact on the scaffold environment.  

Kotov said that his research could find immediate application in bone marrow stem cell research, but he also has broader uses in mind. 'We anticipate using our system for applications in the drug and vaccine discovery field,' he said.  

Rebecca Gillan