保姆细胞在决定免疫细胞生死方面有重要作用

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保姆细胞在决定免疫细胞生死方面有重要作用 ??根据一项由美国国家科学基金（NSF）支持的研究项目结果，“保姆细胞”（Nursecells）在免疫系统对抗感染的T细胞发育过程中决定其生死方面起着重要作用。这一结果发表在6月份的刊物《ExperimentalBiologyandMedicine》上。??免疫系统中的T细胞又称为胸腺细胞，它们存在于胸腔上部的胸腺中，是免疫系统中主要负责对抗外来抗原的细胞。胸腺功能的缺失将导致严重的免疫缺陷以及增

  生物谷报道：根据一项由美国国家科学基金（NSF）支持的研究项目结果，“保姆细胞”（Nurse cells）在免疫系统对抗感染的T细胞发育过程中决定其生死方面起着重要作用。这一结果发表在6月份的刊物《Experimental Biology and Medicine》上。

  免疫系统中的T细胞又称为胸腺细胞，它们存在于胸腔上部的胸腺中，是免疫系统中主要负责对抗外来抗原的细胞。胸腺功能的缺失将导致严重的免疫缺陷以及增加对于感染的易感性。胸腺产生的T细胞作用在于识别外来有害的入侵者。一旦入侵者被识别，T细胞就会尝试消灭被感染的细胞。

  NSF的分子和细胞生物学部门项目主任Eve Barak表示：“在较早的研究中，科学家认为胸腺中的保姆细胞只会消除没有功能的胸腺细胞。而这项研究则显示，保姆细胞在胸腺中的作用要比想象的大得多。”

  胸腺保姆细胞的名字来源于它们与胸腺细胞之间的密切关系。据报道，这些保姆细胞能将多达50个最终将死亡的胸腺细胞吸收入保姆细胞自身的胞体内。

  胸腺保姆细胞最早在1980年被发现。研究项目的主要负责人之一，来自纽约城市大学的生物学家Jerry Guyden表示，这些保姆细胞的存在曾经在科学家之间引起争论，因为科学家们很难相信一个细胞能内生于另一个细胞内。

  胸腺在大部分脊椎动物体内都存在，而且它们的结构和功能类似于人类胸腺。在肉类市场上常常有动物胸腺组织出售。

原始出处:

Experimental Biology and Medicine 232:780-788 (2007)
ORIGINAL RESEARCH ARTICLE

Thymic Nurse Cell Multicellular Complexes in HY-TCR Transgenic Mice Demonstrate Their Association with MHC Restriction
Marcia Martinez*, Michael Samms, Tonya M. Hendrix, Oluwaseun Adeosun, Mark Pezzano and Jerry C. Guyden,1

* Biology Department, Tuskegee University, Tuskegee, Alabama 36088; and Department of Biology, City College of New York, New York, New York 10031

To whom requests for reprints should be addressed at 1 Department of Biology, The City College of New York, 138th Street and Convent Avenue, New York, NY 10031. E-mail: jguyden@ccny.cuny.edu

This study examines thymic nurse cell (TNC) function during T-cell development. It has been suggested that TNCs function in the removal of nonfunctional and/or apoptotic thymocytes and do not participate in major histocompatibility complex restriction. We analyzed TNCs isolated from both normal C57BL/6 mice and C57BL/6 TgN (TCRHY) mice (HY-TCR transgenic mice). Using confocal microscopic analyses of TNCs isolated from C57BL/6 animals, we showed that 75%–78% of the enclosed thymocyte subset was viable, and 87%–90% of these cells expressed both CD4 and CD8. CD4 and CD8 also were expressed on TNC thymocytes isolated from both male and female HY-TCR transgenic mice. The transgenic female thymus was shown to have 17 times more TNCs per milligram of thymus than the transgenic male thymus. TNCs from HY-TCR transgenic females were 8–10 祄 larger than transgenic male TNCs, and the female TNCs contained five times more thymocytes within intracytoplasmic vacuoles, with less than 4% apoptosis. However, more than 42% of the thymocytes within transgenic male TNCs were apoptotic. The large number and size of TNCs containing viable thymocytes in the female transgenic thymus suggest that TNC function is not limited to the removal of apoptotic thymocytes. We believe that the selective uptake of viable double-positive thymocytes by TNCs in C57BL/6 and HY-TCR transgenic female mice provides evidence that this interaction occurs during the process of major histocompatibility complex restriction.


Key Words: thymic nurse cells • MHC restriction • thymocyte development • H-Y TCR Mice