CD44 binds to macrophage mannose receptor on lymphatic endothelium and supports lymphocyte migration via afferent lymphatics – CD44-MRC mediates migration within lymphatics
: CD44-MRC mediates migration within lymphatics
: Salmi M, Karikoski M, Elima K, Rantakari P, Jalkanen S
: 2013
: Circulation Research
: Circ Res
: 12
: 112
: 12
: 1577
: 1582
: 11
: 0009-7330
DOI: https://doi.org/10.1161/CIRCRESAHA.111.300476(external)
RATIONALE:
Macrophage mannose receptor (MRC) is one of the few molecules known to be involved in lymphocyte trafficking via the lymphatic vessels. In endothelial cells of efferent lymphatics, it binds L-selectin on lymphocytes. In afferent lymphatics, MRC mediates trafficking of both normal and malignant L-selectin-negative cells to the draining lymph nodes.
OBJECTIVE:
This work was designed to search for additional lymphocyte ligands of MRC to elucidate how lymphocytes migrate into the draining lymph nodes.
METHODS AND RESULTS:
Using immunoprecipitation and binding studies with natural and recombinant proteins, we show that MRC and CD44 can interact with each other. Fine mapping revealed that the cysteine-rich domain of MRC binds to the chondroitin sulfate side chains of CD44. In vivo homing experiments with MRC- and CD44-deficient mice verified that MRC and CD44 function as a receptor-ligand pair in supporting lymphocyte migration via the afferent lymphatics into the draining lymph nodes.
CONCLUSIONS:
These data identify a new counter-receptor for MRC and reveal CD44 as a new molecule involved in the poorly understood process of lymphocyte transit via the lymphatic vasculature.