Murine lymph node stromal cells increase CD4+ regulatory T cell survival in vitro

GABRIELA LORENA CAMICIA; MARÍA NOEL BADANO; DANIELA LORENZO; ISABEL PIAZZON; IRENE NEPOMNASCHY

Viña del Mar, Chile

Congreso; 9th Latin American Congress of Immunology; 2009

ALAI (Asociación Latinoamericana de Inmunología)

Lymph nodes (LN) stroma provides the microenvironment for immune cell function and regulation. LN stromal cells synthesize the extracellular matrix and secrete diverse cytokines and chemokines. To evaluate their effects on CD4+ regulatory T cell proliferation and apoptosis, LN stroma cell cultures were established. Considering that cathepsin-L deficient mice (CTSLnkt/nkt)  LN show increases in extracellular matrix proteins and in the absolute number of CD4+CD25+Foxp3+ cells, stromas from wild type and CTSLnkt/nkt mice were established. Naive LN cells were co-cultured with stromal cells; Foxp3 expression in the CD4+CD25+ population was measured and apoptosis and proliferation levels were determined (annexin-V staining and carboxyfluorescein succinimidyl ester dilution). Although no basal proliferation was detected, a significant reduction in CD4+CD25+ cell apoptosis was observed in the presence of both stromas. Similar results were obtained using CD4+CD25+ isolated cells. Decreases in apoptosis were dependent on stromal cell concentration and correlated with increases in Bcl-2 expression. Transwell assays only showed a slight reduction in apoptosis. In conclusion, stromal cells increase CD4+ regulatory T cell survival in vitro, involving the antiapoptotic molecule Bcl-2 and stromal contact. These results would contribute to the improvement of regulatory T cell cultures, an important tool for the development of immunological therapies.