Influence of CTSL on B-cell homeostasis.

<p>By acting both on BM B-cell precursors and SC, negatively regulates the BM production and the export of immature B cells to the periphery. As a consequence, the number of blood and spleen TB and LN FM B cells is restricted by CTSL activity. Besides, by affecting the levels of expression of LN ECM components, CTSL would also limit the number of LN niches for FM B cells, cooperating in that way to regulate the number of FM B cells . IB: immature B cells; TB: transitional B cells; FM: follicular mature B cells.