生物谷：樹枝狀細(xì)胞是一種特定的免疫細(xì)胞,，研究人員在5月在線出版的《自然—免疫學(xué)》（Nature Immunology）期刊上報(bào)告說,，一種武裝起來的“殺手”細(xì)胞能夠摧毀重新進(jìn)入淋巴結(jié)中的枝狀細(xì)胞。這種由特定抗原T細(xì)胞殺死的細(xì)胞的死亡,，會(huì)減少其他未受影響的免疫細(xì)胞的激活,，避免過度的免疫反應(yīng)。新結(jié)果推翻了一種主導(dǎo)觀點(diǎn),，即淋巴結(jié)能提供一種阻止活性T細(xì)胞進(jìn)入的限制性環(huán)境,。
效應(yīng)器記憶 CD8+T細(xì)胞是一種免疫“殺手”細(xì)胞，Sallusto和同事發(fā)現(xiàn),，“休眠”的淋巴結(jié)能繼續(xù)阻止以前激活的CD8+T細(xì)胞的進(jìn)入,。然而，當(dāng)感染過程出現(xiàn)炎癥信號(hào)時(shí),，淋巴結(jié)會(huì)被激活,，表達(dá)出一種名為CXCL9的化學(xué)信號(hào)，召集記憶T細(xì)胞涌向血管,。這些記憶細(xì)胞表達(dá)一種能識(shí)別CXCL9的受體CXCR3,。
除了檢查進(jìn)一步的免疫活性外，CXCL9進(jìn)入通道還提供了與病原菌如HIV作斗爭的方法,。新研究將有助于更有效的疫苗和免疫治療方法的開發(fā),。（引自科學(xué)時(shí)報(bào)）
Nature Immunology
Published online: 27 May 2007 | doi:10.1038/ni1469
L-selectin-negative CCR7- effector and memory CD8+ T cells enter reactive lymph nodes and kill dendritic cells
Greta Guarda1, Miroslav Hons1, Silvia F Soriano2, Alex Y Huang3,4, Rosalind Polley3, Alfonso Martín-Fontecha1, Jens V Stein2, Ronald N Germain3, Antonio Lanzavecchia1 & Federica Sallusto1
Abstract
T lymphocytes lacking the lymph node–homing receptors L-selectin and CCR7 do not migrate to lymph nodes in the steady state. Instead, we found here that lymph nodes draining sites of mature dendritic cells or adjuvant inoculation recruited L-selectin-negative CCR7- effector and memory CD8+ T cells. This recruitment required CXCR3 expression on T cells and occurred through high endothelial venules in concert with lumenal expression of the CXCR3 ligand CXCL9. In reactive lymph nodes, recruited T cells established stable interactions with and killed antigen-bearing dendritic cells, limiting the ability of these dendritic cells to activate naive CD4+ and CD8+ T cells. The inducible recruitment of blood-borne effector and memory T cells to lymph nodes may represent a mechanism for terminating primary and limiting secondary immune responses.
Institute for Research in Biomedicine, CH-6500 Bellinzona, Switzerland.
Theodor Kocher Institute, University of Bern, CH-3012 Bern, Switzerland.
National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Present address: Division of Pediatric Hematology/Oncology, Rainbow Babies & Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
Correspondence to: Federica Sallusto1 e-mail: [email protected]
