Research progress on thymus reconstruction / 中国免疫学杂志

Thymus,a main organ for T cell development,plays a pivotal role in adaptive immune response and dealing with the threaten from pathogens and tumors.With the deep understanding of the thymus,people have been realizing that the thymus is extremely sensitive to acute and chronic injuries as well as involution with age.Thymus regeneration can recover its function to a certain level.Up to now,these methods including adoptive thymic epithelial progenitor cells immunotherapy,injection of IL-2 and angiogenesis factor and regulation of c-Met signal are able to promote thymus recovery and T cell regeneration.

Characterization of the expression of cytokeratins 5, 8, and 14 in mouse thymic epithelial cells during thymus regeneration following acute thymic involution / 대한해부학회지

The thymus is a central lymphoid organ for T cell development. Thymic epithelial cells (TECs) constitute a major component of the thymic stroma, which provides a specialized microenvironment for survival, proliferation, and differentiation of immature T cells. In this study, subsets of TECs were examined immunohistochemically to investigate their cytokeratin (CK) expression patterns during thymus regeneration following thymic involution induced by cyclophosphamide treatment. The results demonstrated that both normal and regenerating mouse thymuses showed a similar CK expression pattern. The major medullary TECs (mTEC) subset, which is stellate in appearance, exhibited CK5 and CK14 staining, and the minor mTEC subset, which is globular in appearance, exhibited CK8 staining, whereas the vast majority of cortical TECs (cTECs) expressed CK8 during thymus regeneration. Remarkably, the levels of CK5 and CK14 expression were enhanced in mTECs, and CK8 expression was upregulated in cTECs during mouse thymus regeneration after cyclophosphamide-induced acute thymic involution. Of special interest, a relatively high number of CK5+CK8+ TEC progenitors occurred in the thymic cortex during thymus regeneration. Taken together, these findings shed more light on the role of CK5, CK8, and CK14 in the physiology of TECs during mouse thymus regeneration, and on the characterization of TEC progenitors for restoration of the epithelial network and for concomitant regeneration of the adult thymus.

A mouse thymic epithelial cell line MTEC1 selectively promoted CD_4~+CD_8~-mature thymocytes to proliferate / 中国免疫学杂志

MTEC1 cell line,established in our laboratory,was identified as epithelial cells in nature and derived from ormal Balb/c mouse thymus medulla.To study the impact of MTEC1 cells on thedeveloping of mature thymocytes,we ocultured MTEC1 cells or/and MTECI cell culture supertants(MTEC1—SN)with cortision resistant thymocytesCRT).The results showed that,without anyadditional stimulators,MTEC1 cells could maintain the viability f RT cells,and slightly butsignificantly promote CRT cells to proliferate.MTEC1—SN alone could maintain the viability fCRT cells,but not promote CRT cells to proliferate.Added suboptical doses of Con A into medium,the number of the iable CRT cells and the extent of proliferaton of CRT cells were significantlyincreased when CRT cells was cocultured ith MTECI cells and/or MTEC1—SN.The phenotypes of viable CRT cells after cocultured with MTEC1 cells or TEC1—SN wereanalysed on flow cytometry(FACS).The viable CRT cells were seperated by density cut aftercocultured with MTECI cells or MTEC1—SN for 5 days,then stained with PE-anti-L3T4 and FITC-anti-Ly2 cAbs.The results showed that MTEC1 cells selectively promoted CD4~+CD8-thymocytesto proliferate,the ratio of CD4+CD8~-/CD4~-CD8~+ increased from 1.4 to 3.1.Under thBe conditionof MTEC1 cells cocultured with Con A activated RT ells,MTEC1 cells also mainly promoted CD4~+CD8~-thymocytes to proliferate.MTEC1-SN alone could maintain the iability of CD4~+CD8~-and CD4~-CD8~+thymocytes,andpromoted Con A activated CD4~+CD8~- and CD4~-CD8+thymocytes to proliferate,the propotion oftwo subsets was 34.6?3.5% and 49.7?6.1%.These studies emostrated that MTEC1 cell linepossess selective functions on the intrathymic T cell evelopment.