ISSN:0883-0185    

DOI:10.3109/08830189509056697

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0883-0185    

DOI:10.3109/08830189509056698

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The intestinal lymphoid compartment has a rather stable composition throughout life. However, both during early neonatal development and at high age unique cell populations can be recognized at distinct sites in the intestinal tissue. Directly after birth all intestinal CD3+cells are found in the lamina propria. At this time the epithelium does not contain T cells. These CD3+lamina propria lymphocytes co-express both TCRβand TCRδchains, probably reflecting the expression of a TCRβδheterodimer on the cell surface. Cells with this particular phenotype are present in comparable numbers in the lamina propria of both neonatal euthymic and athymic mice, indicating the thymus-independent nature of these cells. During aging the frequency of TCRαβ+CD8αα+intestinal T cells increases. These cells are also considered to be thymus-independent. The appearance of high numbers of CD4+CD8αα+intestinal T cells in aged mice is even more striking. It is postulated that the neonatal TCRβδ+cells, and probably also the CD4+CD8αα+cells as found in old mice, are intermediates in the extrathymic differentiation pathway of TCRαβ+CD8αα+intestinal T cells.

ISSN:0883-0185    

DOI:10.3109/08830189509056699

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

To define age-associated alterations in the immune system at the molecular level, we have analyzed TCR Vβgene expression patterns at the fetal, neonatal, adult, and advanced ages of mice. In contrast to Vγand VHgenes, Vβgenes rearranged without any preference related to their chromosomal organization. Endogenous superantigen-mediated clonal deletions were registered for the first time at the neonatal stage, presumably reflecting the late developmental appearance of these molecules. Such deletions, once established, were maintained throughout life with little, if any, leakage in this process. Furthermore, bone marrow transplantation and other studies indicated that an involuted thymus maintained its capacity to perform both its functions, i.e. positive and negative selection. Although overall Vβrepertoires showed remarkable stability with advanced age, modifications in expression levels for some Vβ, particularly those associated with the CD8 subset and presumably reflecting antigenic stimulation, were recorded. Mice with lupus and early-life thymic involution were fully capable of deleting endogenous superantigen-reactive Vβclones, and even lupus mice with a genetic defect in the apoptosis-promotingFasgene were normal in this regard. The results indicate that, aside from some anticipated clonal expansions induced by antigenic stimulation, age-associated alterations in immune functions are not caused by any profound changes in the overall TCR repertoire.

ISSN:0883-0185    

DOI:10.3109/08830189509056700

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0883-0185    

DOI:10.3109/08830189509056701

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0883-0185    

DOI:10.3109/08830189509056702

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

The interaction of the endocrine, immune, and nervous systems in modulating each other's activity opens the track for a new way of looking to the effects of aging on each of the three systems. This new approach finds it bases in old times, since evolution shows how we missed for many years a relation between the three systems that was clearly manifested in lower species. In this chapter, the effects of aging on the immune, endocrine and nervous systems are proposed as the consequence of the influences of each system on the others.

ISSN:0883-0185    

DOI:10.3109/08830189509056703

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor