Identification and characterization of a brain-specific antigen enriched in neonatal brain. II. Antigenic stability, species cross-reactivity and tumor cell association

NABSA is a brain-specific antigen enriched in neonatal brain. Microcomplement fixation was used to determine the extent of serological stability of NABSA towards heat denaturation and freeze-thaw denaturation. NABSA antigenic activity was progressively lost from neonatal and adult brain solutions incubated at temperatures above 40°C. All activity was lost above 65°C. Dilute solutions of NABSA were stable at 8°C for at least two weeks and could be frozen and thawed in Tris·phosphate buffer at concentrations above 2 mg/ml with little loss of activity. NABSA was found in every vertebrate species tested. An unusually close structural similarity (a frequent characteristic of both brain-specific antigens and fetal antigens) was demonstrated by serological methods among the mammalian and avian NABSAs. NABSA was detected by microcomplement fixation analysis in 4 out of 16 rat and murine neural clonal tumor cell lines. There was no clear limitation of NABSA to a particular class of neural cell (as defined by the phenotypes of these tumor cell classes) or to rapidly dividing or stationary phase cells. NABSA may be a brain-specific oncofetal antigen (OFA-associated), since it is present in tumor cells of the nervous system and high levels are found in immature brain.

新生脑特异性抗原（NABSA）是一种在新生大脑中富集的脑特异性抗原。采用微量补体结合试验来测定NABSA在热变性和冻融变性条件下的血清学稳定性程度。当新生和成年大脑的溶液在40℃以上温度孵育时，NABSA的抗原活性逐渐丧失。65℃以上时，所有活性全部丧失。NABSA稀溶液在8℃下至少可稳定保存两周，且在三羟甲基氨基甲烷 - 磷酸盐缓冲液中，浓度高于2毫克/毫升时，冻融后活性损失很小。 在所检测的每一种脊椎动物中都发现了NABSA。通过血清学方法证实，哺乳动物和鸟类的NABSA之间存在异常紧密的结构相似性（这是脑特异性抗原和胎儿抗原共有的常见特征）。 通过微量补体结合分析，在16个大鼠和小鼠神经克隆肿瘤细胞系中，有4个检测到了NABSA。NABSA并没有明显局限于某一特定类别的神经细胞（根据这些肿瘤细胞类别的表型来界定），也不局限于快速分裂期或静止期的细胞。NABSA可能是一种脑特异性癌胚抗原（与癌胚抗原相关），因为它存在于神经系统的肿瘤细胞中，且在未成熟大脑中含量较高。