Identification of minor histocompatibility antigens restricted by HLA alleles common in Japanese

次要组织相容性抗原(MHAgs)特异性细胞毒性T淋巴细胞(CTL)的组织表达仅限于造血细胞，可用于异基因造血细胞移植(HCT)后复发白血病/淋巴瘤的免疫治疗。我们采集了26例接受HCT的患者的外周血样，并产生了受日本人群常见的HLA等位基因限制的CTL。首先，我们使用320例接受了人类白细胞抗原相合的供者对的人类白细胞抗原A24阳性患者，研究了BCL2A1/A24差异对临床结果的影响。结果表明，这种差异不太可能增加GVHD，提示这种mHAg可能用于HCT后血液系统恶性肿瘤的免疫治疗。接下来，我们尝试使用优先溶解造血细胞的CTL克隆来鉴定编码人类白细胞抗原-A^*3303限制性男性特异性mhag的基因。利用一组Y染色体缺失突变体LCLS，该基因被缩小到Yq11.221。利用RT-PCR法、…法进一步研究更多的微小基因表达和CTL识别，证明mHAg确实位于TMSB4Y基因的5‘非编码区。第三，对编码人类白细胞抗原-A^*3303和-A^*3101限制性mHAg的mHAG基因(S)进行了鉴定。连锁分析表明，两个针对这些mHAgs的CTL克隆识别出来自同一区域的相似表位(S)，即15q25。通过表达克隆的方法，获得了一个单一的多态基因--组织蛋白H。该基因有三个非同义SNPs，第一个SNPs控制这些CTL克隆的特异性。HLA-A^*3303重组CTL识别终止Arg的10聚体表位，而HLA-A^*3101重组CTL识别终止相同Arg的9聚体表位。用由Ag阴性等位基因编码的Gly取代Arg，完全取消了该肽的结合。Cusespsin H在造血细胞中不表达，但其功能与癌细胞的转移密切相关。因此，我们目前正在质疑这些表位是否对实体瘤的免疫治疗有用。较少

Cytotoxic T lymphocytes(CTL) specific for minor histocompatibility antigens(mHAgs) whose tissue expression is limited to hematopoietic cells are useful for immunotherapy of relapsed leukemia/lymphoma following allogeneic hematopoietic cell transplantation(HCT). We have collected peripheral blood samples 26 patients receiving HCT and generated CTL restricted by HLA alleles commonly seen in Japanese population. First we examined the impact of BCL2A1/A24 disparity on clinical outcome using 320 HLA-A24-positive patients receiving HLA-identical HCT.donor pairs. The results indicate the disparity is unlikely to augment GVHD, suggesting this mHAg may be used for immunotherapy against hematological malignancies after HCT. We next attempted to identify a gene encoding HLA-A^*3303 restricted, male specific mHAg using a CTL clone that preferentially lysed hematopoietic cells. Using a panel of Y chromosome deletion mutant LCLs, the gene was narrowed down to Yq11.221. Further studies using RT-PCR, … More minigene expression and CTL recognition, demonstrated that the mHAg was indeed located in the 5'UTR of TMSB4Y gene. Third, identification of mHAg gene(s) encoding HLA-A^*3303 and -A^*3101-restricted mHAgs was conducted. Linkage analysis demonstrated that two CTL clones specific for these mHAgs recognized a similar epitope(s) from a single region, 15q25. A single polymorphic gene, Cathepsin H, was identified by the aid of expression cloning. This gene has three non-synonymous SNPs and the first one controlled the specificity of these CTL clones. HLA-A^*3303-rectricted CTL recognized 10-mer epitope ending Arg while HLA-A^*3101 -rectricted CTL recognized 9-mer epitope ending the same Arg. Substitution of Arg with Gly which is encoded by Ag-negative allele totally abrogated the binding of the peptide. Cathespsin H is not specifically expressed in hematopoietic cells, but its function is tightly correlated with metastasis of cancer cells. Thus we are currently questioning wheather these epitope is useful for immunotherapy against solid tumors. Less