Butterfield Lisa H, Ribas Antoni, Dissette Vivian B, Lee Yohan, Yang Jin Quan, De la Rocha Pilar, Duran Sonia D, Hernandez Jackie, Seja Elisabeth, Potter Douglas M, McBride William H, Finn Richard, Glaspy John A, Economou James S
Department of Medicine, Surgery and Immunology, Hillman Cancer Center, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA.
Clin Cancer Res. 2006 May 1;12(9):2817-25. doi: 10.1158/1078-0432.CCR-05-2856.
Alpha-fetoprotein (AFP) is a self protein expressed by fetal liver at high levels, but is transcriptionally repressed at birth. AFP is up-regulated in hepatocellular carcinomas, and patients with active disease could have plasma levels as high as 1 mg/mL. We previously identified four immunodominant HLA-A0201-restricted peptides [hAFP(137-145) (PLFQVPEPV), hAFP(158-166) (FMNKFIYEI), hAFP(325-334) (GLSPNLNRFL), and hAFP(542-550) (GVALQTMKQ)] derived from human AFP that could stimulate specific T cell responses in healthy donor peripheral blood lymphocytes in vitro. We conducted a phase I/II clinical trial in which HLA-A0201 patients with AFP-positive hepatocellular carcinoma were immunized with three biweekly intradermal vaccinations of the four AFP peptides pulsed onto autologous dendritic cells (DC). DCs were prepared from adherent peripheral blood mononuclear cells cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4 for 7 days. Sixteen subjects were enrolled and 10 were treated. Peripheral blood lymphocytes were isolated from these patients before, during, and after AFP peptide/DC immunization and were tested ex vivo with MHC tetramer and IFNgamma ELISPOT analysis. Six of 10 subjects expanded statistically significant levels of AFP-specific T cells postvaccine to at least one peptide by MHC tetramer. Also, 6 of 10 subjects increased IFNgamma producing AFP-specific T cell responses to at least one of the peptides postvaccination, by ELISPOT. We conclude that the human T cell repertoire is capable of responding to the AFP self antigen after the administration of AFP peptide-pulsed DC even in an environment of high circulating levels of this oncofetal antigen.
甲胎蛋白（AFP）是一种由胎儿肝脏高水平表达的自身蛋白，但在出生时转录受到抑制。AFP在肝细胞癌中上调，患有活动性疾病的患者血浆水平可能高达1mg/mL。我们之前鉴定了四种免疫显性的HLA-A0201限制性肽[hAFP(137 - 145)（PLFQVPEPV）、hAFP(158 - 166)（FMNKFIYEI）、hAFP(325 - 334)（GLSPNLNRFL）和hAFP(542 - 550)（GVALQTMKQ）]，它们源自人AFP，在体外可刺激健康供体外周血淋巴细胞产生特异性T细胞反应。我们进行了一项I/II期临床试验，对HLA-A0201的AFP阳性肝细胞癌患者进行免疫，每两周皮内接种一次四种负载于自体树突状细胞（DC）上的AFP肽。DC由贴壁外周血单核细胞制备，用粒细胞 - 巨噬细胞集落刺激因子和白细胞介素 - 4培养7天。招募了16名受试者，10名接受了治疗。在AFP肽/DC免疫前、免疫期间和免疫后从这些患者中分离外周血淋巴细胞，并通过MHC四聚体和IFNγ ELISPOT分析进行体外检测。10名受试者中有6名在接种疫苗后通过MHC四聚体检测到针对至少一种肽的AFP特异性T细胞水平有统计学意义的扩增。此外，10名受试者中有6名在接种疫苗后通过ELISPOT检测到针对至少一种肽的产生IFNγ的AFP特异性T细胞反应增加。我们得出结论，即使在这种癌胚抗原循环水平较高的环境中，给予负载AFP肽的DC后，人类T细胞库仍能够对AFP自身抗原产生反应。
