本帖最后由 细胞海洋 于 2012-9-14 20:50 编辑 - m% z2 S3 ^$ k 3 S8 H+ o+ y* D! Q, [ , i! F( T7 n) u3 e4 K: @5 S, R! V( j) EOn the cover: The ability to learn and remember previously encountered pathogens is a hallmark of the vertebrate immune system. CD8+ T cells, called central memory cells (TCM), mediate much more rapid and vigorous immune responses against the viruses that they recognize compared to their uneducated precursors, the naive T cells (TN). In this issue, Sung et al. (pp. 1249–1263) compare, at the single-cell level, the response of TN and TCM to a subcutaneous viral challenge. The invading virions are rapidly transported to the draining lymph nodes, where they infect macrophages that line the periphery of these bean-shaped organs. The image shows a cross-section of a lymph node in which virus-infected macrophages are identified by their yellow-green color. Initially, both TN and TCM reside in the deep T cell area (the dark region in the center of the organ). TCM, unlike TN, expresses CXCR3, a chemokine receptor that enables TCM to sense distant viral infections and to migrate peripherally between the B cell follicles (red) and into the medulla (the blue-green region on the left). This chemokine-dependent redistribution of TCM provides rapid access to viral antigen, which is critical for expedient clearance of the virus and, thus, represents a key molecular feature of immunological memory. Oil on canvas painting by Meghan Perdue. ! b. c# X% L; ]5 g , r* N' ~) W4 c. q) O& w7 y# k& |, j; g) b" A( J; N `" n+ f 作者: exin11 时间: 2012-9-14 21:28
