High B cell production rate in Cathepsin-L deficient mice

BADANO MN; CAMICIA G; A.F. MAGLIOCO; I PIAZZON; I NEPOMNASCHY

Viña del mar

Congreso; 9th Latin American Congress of Immunology; 2009

Cathepsin-L deficient (CTSLnkt/nkt)mice show increases in B lymphocytes number and in the extracellularmatrix (ECM) components in lymph nodes (LN). We investigate themechanisms involved in the high LN B cells numbers in CTSLnkt/nktmice.Neither LN nor spleen showed alterations in basalB cell apoptosis (propidium iodide) and invivo proliferative levels(5-bromo-2´-deoxyuridine) in CTSLnkt/nktmice. When the adhesion molecules that enable the entryof lymphocytes into the LN were studied, an increase in thepercentage of LFA-Ihigh and CD44high inCD19+ cellswas observed. To investigate the B-cellproduction by the bone marrow (BM) -which shows low levels of ECMglycoproteins in CTSLnkt/nktmice- we performed colony-forming unit pre-B (CFU-pre-B)assays in a methylcellulose and IL-7 supplemented medium. At day 7,the number of CTSLnkt/nktBM CFU-pre-B cells was significantly higher than the number of wildtype BM CFU-pre-B cells.These results suggest that the elevated LN B cellsnumbers in CTSLnkt/nktmice, are in part, a consequence ofan increased B lymphopoiesis.We hypothesized that cathepsin-L-probably acting on the ECM composition-plays a role in the regulation of B cell production and theirdistribution in the peripheral lymphoid organs. p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman", serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman", serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman", serif; font-size: 12pt; }