The Different Patterns of Germinal Centers in the Brain

There are different stromal cells in the lymph node called follicular dendritic cells that secrete a chemokine CXCl13. Because they're patchy, they sort of attract patches of B-cell around them. There are many different factors, including CXCl 13, but also S1 gr2 is a receptor for a single lipid. And other receptors, they're important, that really constrain the B-cells to one single germinal center.