CTSL FROM FIBROBLASTIC RETICULAR LYMPH NODE CELLS NEGATIVELY REGULATES CONVERSION OF CD4 CELLS TO THE TREG CELL PHENOTYPE

MAGLIOCO A; CAMICIA G; BADANO N; COSTA H; CAMERANO G; PIAZZON I; NEPOMNASCHY I

Congreso; LIX Reunion anual de SAIC-LXII Reunion anual de SAI; 2014

Saic-SAI

Cathepsin L (CTSL) is a lysosomal cysteine peptidase with diverse and highly specific functions. We and others have shown that CTSL is involved in thymic CD4+ T-cell positive selection. Using CTSLnkt/nkt mice that lack CTSL activity we have previously demonstrated that the absence of CTSL activity correlates with increases both in the number of lymph node (LN) and spleen CD4+CD25+Foxp3+ (Treg) cells and in the ratio between CD4+ Treg and CD4+CD25-Foxp3- (T conv) cells within CD4+ cells. Contrarily, CTSLnkt/nkt and wt mice show no differences both in the number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established demonstrated that the absence of CTSL activity correlates with increases both in the number of lymph node (LN) and spleen CD4+CD25+Foxp3+ (Treg) cells and in the ratio between CD4+ Treg and CD4+CD25-Foxp3- (T conv) cells within CD4+ cells. Contrarily, CTSLnkt/nkt and wt mice show no differences both in the number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established nkt/nkt mice that lack CTSL activity we have previously demonstrated that the absence of CTSL activity correlates with increases both in the number of lymph node (LN) and spleen CD4+CD25+Foxp3+ (Treg) cells and in the ratio between CD4+ Treg and CD4+CD25-Foxp3- (T conv) cells within CD4+ cells. Contrarily, CTSLnkt/nkt and wt mice show no differences both in the number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established nkt/nkt and wt mice show no differences both in the number of thymic CD4+CD8- Foxp3+ cells or in the ratio between Treg and Tconv cells within CD4+CD8- thymocytes, suggesting that the increase in the number of LN Treg cells is established in the periphery of mutant mice. Herein we analyzed whether conversion is involved in the increase in the Treg peripheral cell number in CTSLnkt/nkt mice and the involvement of LN stromal cells (LNSC). LN CD4+CD25-Foxp3-cells activated with anti-CD3, anti-CD28 and IL-2 but without exogenous TGF-â1 were cultivated with supernatants (sn) from mutant or wt LNSC. Conversion was with supernatants (sn) from mutant or wt LNSC. Conversion was cells (LNSC). LN CD4+CD25-Foxp3-cells activated with anti-CD3, anti-CD28 and IL-2 but without exogenous TGF-â1 were cultivated with supernatants (sn) from mutant or wt LNSC. Conversion was with supernatants (sn) from mutant or wt LNSC. Conversion was nkt/nkt mice and the involvement of LN stromal cells (LNSC). LN CD4+CD25-Foxp3-cells activated with anti-CD3, anti-CD28 and IL-2 but without exogenous TGF-â1 were cultivated with supernatants (sn) from mutant or wt LNSC. Conversion was with supernatants (sn) from mutant or wt LNSC. Conversion was â1 were cultivated with supernatants (sn) from mutant or wt LNSC. Conversion was significantly increased by the addition of mutant vs wt LNSCsn (i.e. percentage of Treg cells in CTSLnkt/nkt Tconv cells cultured with mutant or wt LNSCsn: 15.8±2 vs 7.3±1.2, n=3, p<0.01). with mutant or wt LNSCsn: 15.8±2 vs 7.3±1.2, n=3, p<0.01). nkt/nkt Tconv cells cultured with mutant or wt LNSCsn: 15.8±2 vs 7.3±1.2, n=3, p<0.01). These Treg percentages significantly diminished in the presence of a TGF-â1 inhibitor. The mutant LNSC produced more TGF-â1â1 inhibitor. The mutant LNSC produced more TGF-â1 than that of wt mice (mutant vs wt LNSC sn, in pg/ml: 1618±198 vs 245±12.3, p>0.01, n=3; measured by ELISA). More than 97% of both mutant and wt LN stromal cell lines were gp38 + CD35- CD21-, indicating a fibroblastic reticular phenotype. These resu lts indicate that conversion can play a role in the increase of Treg cells in the periphery of CTSLnkt/nkt mice, being TGF-â productionnkt/nkt mice, being TGF-â production by fibroblastic reticular LN stromal cells involved. Moreover, they suggest that CTSL is able to negatively regulate the conversion to Treg cells in non immunoprivileged sites.