Molecular-based analysis of HLA class I processing machinery defects in human melanoma

黑色素瘤T细胞免疫治疗中的一个重要问题是由于黑色素瘤相关抗原和/或HLAI类抗原的丢失而导致的免疫逃逸现象。该研究的带头人一直在分析黑色素瘤细胞中HLAI类分子下调的机制。在本研究中，利用抗黑色素瘤相关抗原(MART-1，gp100，酪氨酸酶)和与抗原处理机制相关的分子(TAP-1，TAP-2，LMP-2，LMP-7，LMP-10，Z，Delta，Tapating，Calnexin，Calreticlin)的单抗，对人类黑色素瘤HLAI类加工机制缺陷的分子分析进行了研究。和HLAI类(HLAI类-重链、HLAI类-轻链)。首席调查员已经在福尔马林固定、石蜡包埋的组织切片中找到了所有这些单抗的抗原修复方法。首席调查员发现以下几点：1)黑色素瘤相关抗原(MART-1、gp100、酪氨酸酶)在原发…中高表达更多的黑色素瘤病变。但在某些转移性黑色素瘤皮损中表达下调，特别是在黑色素含量低的皮损中。2)在与抗原处理机制相关的分子中，Delata和钙网蛋白在原发灶和转移灶中普遍表达。3)HLAI类重链和轻链表达明显下调。4)HLAI类表达与TAP-1/TAP-2下调密切相关。5)CD8浸润与HLAI类下调呈负相关，提示HLAI类表达是黑色素瘤相关抗原呈递给CD8T细胞所必需的，TAP-1和TAP-2是参与HLAI类下调最多的分子。此外，这些数据还表明，这些分子的异常与人类黑色素瘤的免疫逃逸机制有关。较少

One of the large concerns in melanoma T cell based immunotherapy is the immune escape phenomenon resulting from loss of melanoma associated antigens and/or HLA class I. The head investigator has been analyzing the mechanisms of down regulation of HLA class I in melanocytic cells.In the present study, molecular-based analysis of HLA class I processing machinery defects in human melanoma was investigated using monoclonal antibodies to melanoma associated antigens (MART-1, gp100, tyrosinase), to molecules associated with antigen processing machinery (TAP-1, TAP-2, LMP-2, LMP-7, LMP-10, Z, Delta, Tapacin, Calnexin, Calreticulin), and to HLA class I (HLA class I-heavy chain, HLA class I-light chain). The head investigator already found the antigen-retrieval method for all these monoclonal antibodies in formalin-fixed, paraffin-embedded tissue sections.The head investigator found the following points :1)Melanoma associated antigens (MART-1, gp100, tyrosinase) were expressed highly in primary … More melanoma lesions. However, these expressions were down regulated in some metastatic melanoma lesions, especially in the lesions with low melanin content.2)Among the molecules associated with antigen processing machinery, delata and calreticulin were ubiquitously expressed in primary and metastatic lesions. Expression of TAP-1 and TAP-2 were remarkably down regulated especially in metastatic lesions.3)Expression of HLA class I heavy chain and light chain were remarkably down regulated in metastatic lesions.4)There was a close association between HLA class I and TAP-1/TAP-2 down regulation.5)There was an inverse association between CD8 infiltration and HLA class I down regulation.These data suggest that HLA class I expression is necessary for presenting melanoma associated antigens to CD8 T cells and TAP-1 and TAP-2 are most involved molecules in HLA class I down regulation. Also these data suggest that abnormality of these molecules are associated with immune escape mechanism in human melanoma. Less