Xia M Q, Tone M, Packman L, Hale G, Waldmann H
Department of Pathology, University of Cambridge, GB.
Eur J Immunol. 1991 Jul;21(7):1677-84. doi: 10.1002/eji.1830210714.
The CAMPATH-1 (CDw52) antigen has been purified from human spleen. The antigenic epitope is heat stable but sensitive to mild alkali treatment. Experiments with phosphatidylinositol-specific phospholipase C indicate that it is anchored by a glycosylphosphatidylinositol (GPI) anchor. An N-terminal sequence of 11 amino acids was determined, followed by an abrupt stop. Using short overlapping mixed oligonucleotide primers, cDNA synthesized from the mRNA of a human B cell line was amplified by the polymerase chain reaction. The product was used to isolate cDNA clones and the full amino acid sequence of the CAMPATH-1 antigen was deduced. It consists of 37 amino acid residues plus a 24-residue signal peptide. It has all the features expected for a GPI-anchored membrane protein except that the predicted mature protein is remarkably short, comprising no more than 18 residues and possibly as few as 12 (depending on the GPI linkage site). Potential attachment sites for carbohydrate are present and it is shown that the antigen contains N-linked oligosaccharide(s). This structure accounts for the known properties of the antigen, though the exact reasons why it is such a good target for cell lysis in vitro and in vivo are not yet clear.
CAMPATH-1（CDw52）抗原已从人脾脏中纯化出来。该抗原表位对热稳定，但对温和的碱处理敏感。用磷脂酰肌醇特异性磷脂酶C进行的实验表明，它通过糖基磷脂酰肌醇（GPI）锚定。确定了11个氨基酸的N端序列，随后是一个突然终止。使用短的重叠混合寡核苷酸引物，通过聚合酶链反应扩增从人B细胞系的mRNA合成的cDNA。该产物用于分离cDNA克隆，并推导CAMPATH-1抗原的完整氨基酸序列。它由37个氨基酸残基加上一个24个残基的信号肽组成。它具有GPI锚定膜蛋白所预期的所有特征，只是预测的成熟蛋白非常短，不超过18个残基，可能少至12个（取决于GPI连接位点）。存在碳水化合物的潜在附着位点，并且表明该抗原含有N-连接的寡糖。这种结构解释了该抗原的已知特性，尽管它在体外和体内成为细胞裂解的良好靶标的确切原因尚不清楚。
