Kantor R R, Albino A P, Ng A K, Ferrone S
Cancer Res. 1986 Oct;46(10):5223-8.
By analyzing human melanoma cells with monoclonal antibodies (MoAb) we have identified four melanoma associated antigens with distinct tissue distribution and structural properties. They include the high molecular weight melanoma associated antigen (MAA), the Mr 120,000 MAA, the Mr 100,000 MAA, and the cytoplasmic MAA defined by MoAb 465.12. Previous studies have shown that these antigens may be useful markers to characterize the biology of melanoma cells and to develop immunodiagnostic and immunotherapeutic approaches to melanoma. In the present investigation pulse-chase intrinsic labeling studies combined with the biosynthetic inhibitor tunicamycin and with enzymatic degradations with endoglycosidase H have shown that the determinants recognized by the MoAb utilized are expressed on the core protein of the molecules. Furthermore the four MAAs are highly glycosylated with N-linked carbohydrate chains and are synthesized as precursors which bear endoglycosidase H-sensitive chains. The high molecular weight (Mr 500,000/280,000) MAA displays a major precursor with a molecular weight of 240,000 which expresses the epitopes recognized by the anti-high molecular weight MAA MoAbs 149.53, 225.28S, and 763.74T. This precursor has an apparent molecular weight of 220,000 when cells are grown in the presence of tunicamycin. The Mr 89,000 and Mr 36,000 subunits of the Mr 125,000 MAA have biosynthetic precursors with molecular weights of 76,000 and 25,000. Endoglycosidase H digestion of the Mr 76,000 precursor produces a Mr 46,000 polypeptide. The Mr 100,000 MAA has a Mr 87,000 biosynthetic precursor. The cytoplasmic MAA (Mr 100,000, 75,000, 72,000, and 25,000) has a single precursor with a molecular weight of 75,000 which appears as a Mr 60,000 polypeptide after endoglycosidase H digestion. Characterization of the biosynthesis of the four MAAs will contribute to the development of approaches to modulate their expression and shedding by melanoma cells.
通过用单克隆抗体（MoAb）分析人黑色素瘤细胞，我们鉴定出了四种具有不同组织分布和结构特性的黑色素瘤相关抗原。它们包括高分子量黑色素瘤相关抗原（MAA）、分子量为120,000的MAA、分子量为100,000的MAA以及由MoAb 465.12定义的细胞质MAA。先前的研究表明，这些抗原可能是表征黑色素瘤细胞生物学特性以及开发黑色素瘤免疫诊断和免疫治疗方法的有用标志物。在本研究中，脉冲追踪内在标记研究结合生物合成抑制剂衣霉素以及用内切糖苷酶H进行的酶促降解表明，所使用的MoAb识别的决定簇在分子的核心蛋白上表达。此外，这四种MAA都高度糖基化，带有N-连接的碳水化合物链，并且以前体形式合成，这些前体带有对内切糖苷酶H敏感的链。高分子量（分子量500,000/280,000）的MAA显示出一种主要前体，分子量为240,000，它表达了抗高分子量MAA的MoAb 149.53、225.28S和763.74T识别的表位。当细胞在衣霉素存在下生长时，这种前体的表观分子量为220,000。分子量为125,000的MAA的89,000和36,000亚基具有分子量为76,000和25,000的生物合成前体。对分子量为76,000的前体进行内切糖苷酶H消化产生一种分子量为46,000的多肽。分子量为100,000的MAA具有一个分子量为87,000的生物合成前体。细胞质MAA（分子量100,000、75,00憨揣封废莩肚凤莎脯极0、72,000和25,000）具有一个分子量为75,000的单一前体，在进行内切糖苷酶H消化后呈现为分子量为60,000的多肽。对这四种MAA生物合成的表征将有助于开发调节黑色素瘤细胞对其表达和脱落的方法。
