Department of Surgery, Washington University School of Medicine, Box 8109, 3328 CSRB, 660 South Euclid Avenue, Saint Louis, MO 63110, USA.
Breast Cancer Res Treat. 2011 May;127(1):81-9. doi: 10.1007/s10549-010-0975-z. Epub 2010 Jun 11.
Mammaglobin-A (MGBA), a 10-kD protein, is over expressed in 80% of primary and metastatic human breast cancers. Breast cancer patients demonstrate high frequencies of CD8(+) cytotoxic T lymphocytes (CTL) specific to MGBA. Defining CD8(+) CTL responses to HLA class I-restricted MGBA-derived epitopes assumes significance in the context of our ongoing efforts to clinically translate vaccine strategies targeting MGBA for prevention and/or treatment of human breast cancers. In this study, we define the CD8(+) CTL response to MGBA-derived candidate epitopes presented in the context of HLA-B7, which has a frequency of 17.7% in Caucasian and 15.5% in African American populations. We identified seven MGBA-derived candidate epitopes with high predicted binding scores for HLA-B7 using a computer algorithm. Membrane stabilization studies with TAP-deficient T2 cells transfected with HLA-B7 indicated that MGBA B7.3 (VSKTEYKEL), B7.6 (KLLMVLMLA), B7.7 (NPQVSKTEY), and B7.1 (YAGSGCPLL) have the highest HLA-B7 binding affinities. Further, two CD8(+) CTL cell lines generated in vitro against T2.B7 cells individually loaded with MGBA-derived candidate epitopes showed significant cytotoxic activity against MGBA B7.1, B7.3, B7.6, and B7.7. In addition, the same CD8(+) CTL lines lysed the HLA-B7(+)/MGBA(+) human breast cancer cell line DU-4475 but had no significant cytotoxicity against HLA-B7(-) or MGBA(-) breast cancer cell lines. Cold-target inhibition studies strongly suggest that MGBA B7.3 is an immunodominant epitope. In summary, our results define HLA-B7-restriced, MGBA-derived, CD8(+) CTL epitopes with all of the necessary features for developing novel vaccine strategies against HLA-B7 expressing breast cancer patients.
乳腺珠蛋白-A（MGBA）是一种 10kD 蛋白，在 80%的原发性和转移性人乳腺癌中过度表达。乳腺癌患者表现出针对 MGBA 的高频率 CD8+细胞毒性 T 淋巴细胞（CTL）特异性。在我们正在努力将针对 MGBA 的疫苗策略从临床转化为预防和/或治疗人类乳腺癌的背景下，定义针对 HLA 类 I 限制的 MGBA 衍生表位的 CD8+CTL 反应具有重要意义。在这项研究中，我们定义了在 HLA-B7 背景下针对 MGBA 衍生候选表位的 CD8+CTL 反应，HLA-B7 在白种人群中的频率为 17.7%，在非裔美国人中的频率为 15.5%。我们使用计算机算法鉴定了七种具有高预测 HLA-B7 结合评分的 MGBA 衍生候选表位。用 TAP 缺陷的 T2 细胞转染 HLA-B7 的膜稳定研究表明，MGBA B7.3（VSKTEYKEL）、B7.6（KLLMVLMLA）、B7.7（NPQVSKTEY）和 B7.1（YAGSGCPLL）具有最高的 HLA-B7 结合亲和力。此外，针对 T2.B7 细胞分别加载 MGBA 衍生候选表位体外生成的两种 CD8+CTL 细胞系对 MGBA B7.1、B7.3、B7.6 和 B7.7 表现出显著的细胞毒性活性。此外，相同的 CD8+CTL 系裂解 HLA-B7(+)/MGBA(+)人乳腺癌细胞系 DU-4475，但对 HLA-B7(-)或 MGBA(-)乳腺癌细胞系没有显著的细胞毒性。冷靶抑制研究强烈表明，MGBA B7.3 是一种免疫优势表位。总之，我们的结果定义了具有开发针对表达 HLA-B7 的乳腺癌患者的新型疫苗策略所需的所有特征的 HLA-B7 限制的 MGBA 衍生 CD8+CTL 表位。
