反復(fù)暴露于病原體及以殺死病原體為使命的記憶性CD8+ T-細(xì)胞的生成,，被認(rèn)為會(huì)導(dǎo)致事先存在的記憶性T-細(xì)胞存量的消耗,，以保持記憶腔的總體大小不變,。但用小鼠進(jìn)行的新的研究工作表明,，記憶性CD8+ T-細(xì)胞腔的大小在免疫之后會(huì)增加,，而且新的記憶性CD8+ T-細(xì)胞的生成并不會(huì)顯著減少事先存在的記憶性CD8+ T-細(xì)胞的數(shù)量,。關(guān)于哺乳動(dòng)物宿主CD8+ T-細(xì)胞數(shù)量能根據(jù)免疫經(jīng)驗(yàn)發(fā)生適應(yīng)性變化的發(fā)現(xiàn),，對(duì)于疫苗的生產(chǎn)可能具有重要意義，因?yàn)槲覀円苍S有可能大量引入特異性CD8+ T-細(xì)胞,，而不會(huì)影響以前就有的,、針對(duì)其他感染的免疫能力。（生物谷Bioon.com）

生物谷推薦原始出處：

Nature 457, 196-199 (8 January 2009) | doi:10.1038/nature07486

Memory CD8 T-cell compartment grows in size with immunological experience

Vaiva Vezys1,2,4, Andrew Yates3,4, Kerry A. Casey1, Gibson Lanier2, Rafi Ahmed2, Rustom Antia3 & David Masopust1,2

1 Department of Microbiology and Center for Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
2 Emory Vaccine Center, Emory University School of Medicine, and,
3 Department of Biology, Emory University, Atlanta, Georgia 30322, USA
4 These authors contributed equally to this work.

Memory CD8 T cells, generated by natural pathogen exposure or intentional vaccination, protect the host against specific viral infections1. It has long been proposed that the number of memory CD8 T cells in the host is inflexible, and that individual cells are constantly competing for limited space2, 3. Consequently, vaccines that introduce over-abundant quantities of memory CD8 T cells specific for an agent of interest could have catastrophic consequences for the host by displacing memory CD8 T cells specific for all previous infections4, 5, 6. To test this paradigm, we developed a vaccination regimen in mice that introduced as many new long-lived memory CD8 T cells specific for a single vaccine antigen as there were memory CD8 T cells in the host before vaccination. Here we show that, in contrast to expectations, the size of the memory CD8 T-cell compartment doubled to accommodate these new cells, a change due solely to the addition of effector memory CD8 T cells. This increase did not affect the number of CD4 T cells, B cells or naive CD8 T cells, and pre-existing memory CD8 T cells specific for a previously encountered infection were largely preserved. Thus, the number of effector memory CD8 T cells in the mammalian host adapts according to immunological experience. Developing vaccines that abundantly introduce new memory CD8 T cells should not necessarily ablate pre-existing immunity to other infections.