Selective support of a mouse thymus epithelial cell line （MTEC1） to the viability and proliferation of CD4＋CD8—,CD4^—CD8^—,and CD4^＋CD8^＋thymocytes in vitro

The MTEC1 cell line,established in our laboratory,is a normal epithelial cell line derived from thymus medulla of Balb/c mice and these cells constituteively produce multiple cytokines.The selection of thymic microenvironment on developing T cells was investigated in an in vitro system.Unseparated fresh thymocytes from Balb/c mice were cocultured with MTEC1 cells or/and MTEC1-SN,then,the viability,proliferation and phenotypes of cultured thymocytes were assessed.Without any exogenous stimulus,both MTEC1 cells and MTEC1-SN were able to maintain the viability of thymocytes,while only the MTEC1 cells,not the MTEC1-SN,could directly activate thymocytes to exhibit moderate proliferation,indicating that the proliferative signal is delivered through cell surface interatcions of MTEC1 cells and thymocytes.Phenotype analysis on FACS of viable thymocytes after coculture revealed that MTEC1 cells preferentially activate the subsets of CD4^ CD8^-,CD4^ CD^8 and CD^4- CD^8- thymocytes;whereas MTEC1-SN preferentially maintained the viability of CD4^ CD^8- and CD4^-CD8^ thymocyte subsets.For the Con A-activated thymocytes.both MTEC1 cells and MTEC1-SN provided accessory signal(s) to significantly increase the number of viable cells and to markedly enhance the proliferation of thymocytes with virtually equal potency,phenotyped as CD4^ CD8^-,CD4^-CD8^ ,and CD^4-CD8^-subests,In summary,MTEC1 cells displayed Selection of thymic epithelial cells on thymocyte subsets. selective support to the different thymocyte subsets,and the selectivity is dependent on the status of thymocytes.

Selective support of a mouse thymus epithelial cell line (MTEC1) to the viability and proliferation of CD4~+CD8~-,CD4~- CD8~- , and CD4~+CD8~+ thymocytes in vitro

The MTEC1 cell line, established in our laboratory, is a normal epithelial cell line derived from thymus medulla of Balb/c mice and these cells constitutively produce multiple cytokines. The selection of thymic microenvironment on developing T cells was investigated in an in vitro system. Un-separated fresh thymocytes from Balb/c mice were cocul-tured with MTECl cells or/and MTEC1-SN,then,the viability, proliferation and phenotypes of cultured thymocytes were assessed. Without any exogenous stimulus, both MTECl cells and MTECl -SN were able to maintain the viability of thymocytes, while only the MTECl cells, not the MTECl -SN, could directly activate thymocytes to exhibit moderate proliferation, indicating that the proliferative signal is delivered through cell surface interactions of MTECl cells and thymocytes. Phenotype analysis on FACS of viable thymocytes after coculture revealed that MTECl cells preferentially activate the subsets of CD4+ CDS", CD4+ CD8+ and CD4- CD8- thymocytes; whereas MTEC1- SN preferentially maintained the viability of CD4+ CD8- and CD4-CD8+ thymocyte subsets. For the Con A-activated thymocytes, both MTEC1 cells and MTEC1-SN provided accessory signal(s) to significantly increase the number of viable cells and to markedly enhance the proliferation of thymocytes with virtually equal potency, phenotyped as CD4+CD8-, CD4-CD8+, and CD4- CD8- subsets. In summary, MTEC1 cells displayedselective support to the different thymocyte subsets , and the selectivity is dependent on the status of thymocytes.