Mai J K, Winking R, Ashwell K W
Institute of Neuroanatomy, H.-Heine University, Düsseldorf, Germany.
J Comp Neurol. 1999 Feb 8;404(2):197-211.
The expression of the terminal saccharide determinant CD15 (3[a1-3]-fucosyl-N-acetyl-lactosamine) was evaluated in the central auditory system of the human developing brain by using monoclonal antibodies against this epitope. CD15 immunoreactivity was first observed in the ventral cochlear nucleus at 10 weeks of gestation, whereas the dorsal cochlear nucleus became positive from 13 weeks of gestation. In both nuclei, the intensity of immunoreactivity increased until 16 weeks of gestation and lasted until 25 weeks of gestation. In the inferior colliculi, CD15 was poorly expressed in the central nucleus from 13 to 23 weeks of gestation and later with moderate levels until birth. Within the medial geniculate nucleus, a biphasic pattern of expression was observed with peaks around 14-17 and 21-24 weeks of gestation. Heterogeneous expression in the medial geniculate nucleus, which was associated either with neurons or the neuropil, allowed distinction of subnuclei. In many of the auditory pathway structures (e.g., ventral cochlear nucleus and central nucleus of the inferior colliculus), a heterogeneous pattern of CD15 expression in the form of repeating parallel bands, possibly related to tonotopic organization, became transiently apparent around 23 weeks of gestation, whereas in the magnocellular part of the medial geniculate nucleus, a striking modular or compartmental arrangement of immunoreactive structures (which could also be associated with tonotopic organization) was also noted at about 23 weeks of gestation. We propose that the initiation of CD15 expression in each nucleus heralds the appearance of functional contacts and that high levels of neuropil labeling are related to the formation of nonstabilized synaptic contacts. Thus, transient CD15 expression in the central auditory system is possibly correlated with phases of functional plasticity in this pathway.
利用针对该表位的单克隆抗体，在人类发育中大脑的中枢听觉系统中评估了末端糖基决定簇CD15（3[α1-3]-岩藻糖基-N-乙酰乳糖胺）的表达。妊娠10周时，在蜗腹侧核首次观察到CD15免疫反应性，而蜗背侧核从妊娠13周开始呈阳性。在这两个核中，免疫反应性强度在妊娠16周前增加，并持续至妊娠25周。在下丘中，妊娠13至23周期间，中央核中CD15表达较弱，之后表达水平中等直至出生。在内侧膝状核内，观察到双相表达模式，在妊娠14 - 17周和21 - 24周左右出现峰值。内侧膝状核中的异质性表达与神经元或神经纤维网相关，可区分亚核。在许多听觉通路结构中（如蜗腹侧核和下丘中央核），妊娠23周左右，以重复平行带形式出现的CD15异质性表达模式（可能与音频定位组织有关）短暂显现，而在妊娠23周左右，在内侧膝状核的大细胞部分也注意到免疫反应性结构的显著模块化或分区排列（也可能与音频定位组织有关）。我们提出，每个核中CD15表达的起始预示着功能性联系的出现，而高水平的神经纤维网标记与不稳定突触联系的形成有关。因此，中枢听觉系统中CD15的短暂表达可能与此通路中功能可塑性的阶段相关。
