The lymphatic vasculature forms a second circulatory system that drains extracellular fluid
from the tissues and provides an exclusive environment in which immune cells can
encounter and respond to foreign antigen. Although equally important for the functioning of
both the cardiovascular and immune systems, there is only a rudimentary knowledge of the
molecular biology of lymphatics, owing to longstanding difficulties in identifying and isolating
lymphatic endothelial cells. Recently, however, a number of interesting molecules have …