Wagner S N, Wagner C, Schultewolter T, Goos M
Klinik und Poliklinik für Dermatologie, Venerologie und Allergologie, Universitätsklinikum Essen, Germany.
Cancer Immunol Immunother. 1997 Jun;44(4):239-47. doi: 10.1007/s002620050379.
Pmel17/gp100-encoded tumor-associated antigens are recognized by cytotoxic T lymphocytes in melanoma patients and may represent attractive target antigens for immuno- and gene-therapeutic strategies. An important prerequisite for identification and monitoring of melanoma patients that could potentially benefit from Pmel17/gp100-based immuno- and gene-therapies is the detailed knowledge of Pmel17/gp100 expression in vivo. Immunophenotyping is considerably hampered by the different immunoreactivities of Pmel17/gp100-reactive antibodies. Therefore, we analyzed an extended series of different primary normal and malignant human tumor specimens for Pmel17/gp100 expression at the mRNA level. Transcripts were detectable in all malignant melanoma tissue specimens representing all stages of tumor progression, with significant levels even in early and amelanotic melanoma lesions. In contrast, normal melanocytes exhibited significantly less Pmel17/gp100 mRNA in vivo, as determined by comparative in situ hybridization. Tissue specimens from the retina and substantia nigra also contained Pmel17/gp100 mRNA, whereas other normal and malignant human tissues were negative. As determined by comparative in situ hybridisation and HMB-45 immunostaining, even tumor tissue lacking Pmel17/gp100 immunoreactivity contained Pmel17/gp100 transcripts. Our results indicate a melanocytic-cell-lineage-restricted expression of Pmel17/gp100 with significant transcript levels in all stages of melanoma progression, including early and amelanotic melanoma lesions, and a significantly differential expression between melanoma cells and normal melanocytes in vivo. Owing to its higher sensitivity, phenotyping of individual tumor specimens by mRNA expression analysis seems to be more valuable than phenotyping by immunostaining.
Pmel17/gp100编码的肿瘤相关抗原可被黑色素瘤患者的细胞毒性T淋巴细胞识别，可能是免疫治疗和基因治疗策略中有吸引力的靶抗原。详细了解Pmel17/gp100在体内的表达情况，是识别和监测可能从基于Pmel17/gp100的免疫治疗和基因治疗中获益的黑色素瘤患者的重要前提。Pmel17/gp100反应性抗体的不同免疫反应性极大地阻碍了免疫表型分析。因此，我们分析了一系列不同的原发性正常和恶性人类肿瘤标本，以检测其在mRNA水平上的Pmel17/gp100表达。在代表肿瘤进展所有阶段的所有恶性黑色素瘤组织标本中均可检测到转录本，甚至在早期和无色素性黑色素瘤病变中也有显著水平。相比之下，通过比较原位杂交确定，正常黑素细胞在体内表现出明显较少的Pmel17/gp100 mRNA。视网膜和黑质的组织标本也含有Pmel17/gp100 mRNA，而其他正常和恶性人类组织均为阴性。通过比较原位杂交和HMB-45免疫染色确定，即使缺乏Pmel17/gp100免疫反应性的肿瘤组织也含有Pmel17/gp100转录本。我们的结果表明，Pmel17/gp100的表达受黑素细胞谱系限制，在黑色素瘤进展的所有阶段，包括早期和无色素性黑色素瘤病变中，转录水平均显著，且在体内黑色素瘤细胞与正常黑素细胞之间存在显著差异表达。由于其更高的敏感性，通过mRNA表达分析对单个肿瘤标本进行表型分析似乎比通过免疫染色进行表型分析更有价值。
