Alterations in Hemapoiesis in Cathepsin L Mutant Mice.

LOMBARDI GABRIELA; COSTA HÉCTOR; BURZIN DALIA; MUNDIÑANO JULIANA; MEISS ROBERTO; PIAZZON ISABEL; NEPOMNASCHY IRENE

Córdoba Argentina

Congreso; VII Congreso Latinoamericano de Inmunología; 2005

SAI

CTSLnkt mice have a mutation in the cathepsin L (Ctsl) gene. We have previously shown that lymph nodes from these mice are hypertrophied, with a significant increment in the number of T CD8 and B220 cells. These alterations correlate with increases in the expression of extracellular matrix (ECM) components in lymph nodes. No alterations in basal proliferation or apoptosis levels of B220 and CD8 populations were detected. In the thymus of CTSLnkt, which shows an augmented output of CD8 cells, ECM components are markedly decreased. Here we report that CTSLnkt  mice show an increase in the number of bone marrow (BM) hematopoietic cells (350±10 in control vs 428±10 in CTSLnkt mice, p<0.05, number±SD,N=5, in 10 high power field). A clear decrease in fibronectin, laminin, and collagen type I and IV expression was observed in CTSLnkt BM. CTSLnkt mice show an increased daily output of B cells from the BM (2.1x106±0.6 vs16.7x106±6,p<0.05) and increased numbers of neutrophils and reticulocytes in blood. These results indicates that a mutation in CTSL gene is able to alter the BM ECM components and the production of BM hematopoietic cells, and that these changes correlate both with increases in lymph node B220 cell numbers, and neutrophil and reticulocyte numbers in blood.