胃癌免疫治疗新趋势：个体化肽疫苗

胃癌是恶性肿瘤中的常见病种,其肿瘤相关的病死率占全世界第三位,经传统手术及放化疗治疗后胃癌的生存率仍然很低。生物免疫治疗中肿瘤疫苗的研究在近几年取得了重大进步,根据肿瘤患者的个体遗传基因结构或蛋白表达的不同,选择个体化的肿瘤疫苗可以进一步提高治疗效果。个体化肿瘤抗原高表达肽疫苗、负载的树突状细胞疫苗以及个体化多肽疫苗等已在胃癌免疫治疗的临床转化研究中取得了很多成果,个体化肽疫苗与放化疗、分子靶向治疗等其他治疗联合应用可以有效提高临床疗效。本文介绍个体化肽疫苗在胃癌领域的临床转化研究进展、其与化疗、放疗等多学科结合的综合治疗模式及其相关疗效评价等免疫治疗临床转化的新思路和新方法。     

人类肿瘤抗原肽的获得与肿瘤疫苗

在肿瘤疫苗的研究中,人们一直期望并努力寻找肿瘤特异性抗原肽。自从癌基因和抑癌基因发现以来,人们相信确实存在着肿瘤特异性抗原。近年来随着一些方法的改进和应用,相继有了一些可喜的发现,这无疑给肿瘤疫苗的发展奠定了良好的基础。     

修饰的肿瘤抗原肽疫苗及其在肿瘤治疗中的应用

采用修饰的肽配体和佐剂增强细胞毒性T细胞(CTL)应答效应方法合成的肿瘤抗原肽疫苗,主要包括恶性黑色素瘤分化抗原来源、人表皮生长因子受体2(HER2)来源、癌胚抗原(CEA)来源、NY-ESO-1抗原等来源的肽疫苗.目前,其疫苗的修饰方法、设计原理和提高CTL的应答效应机制的研究进展迅速,且取得较为满意的临床疗效.     

肿瘤免疫治疗的新策略—肿瘤肽疫苗

肿瘤抗原诱导杀伤性Ｔ细胞（ＣＴＬ）抗瘤免疫效应的第一步，是抗原在胞浆内被降解成短肽，与ＭＨＥＩ类分子结合，共同表达于细胞表面，为Ｔ细胞所识别。与ＭＨＣＩ类分子结合的短肽（抗原肽）需符合特定的ＭＨＣＩ类限制性基模。人工合成与特定ＭＨＣＩ类基模匹配的肿瘤抗原肽，作为肽疫苗用于肿瘤免疫治疗是一新的肿瘤治疗策略。本文综述了该领域初期研究结果及存在的一些问题。     

HLA—G蛋白在肿瘤组织及患者血清中的表达及其在肿瘤免疫逃逸中的作用

随着对人类白细胞抗原G（HLA—G）蛋白作用机制的深入了解,越来越多的研究发现HLA—G与肿瘤的免疫逃逸密切相关。大量研究显示在肿瘤患者的血浆、肿瘤组织中均可检测到HLA—G蛋白、mRNA的表达。     

肿瘤疫苗潜在的靶抗原——癌基因蛋白

近年来随着ＭＨＣ分子对抗原识别理论的阐明以及癌基因结构和功能的深入研究,以ＭＨＣ－癌基因抗原肽为基础旨在诱导ＣＤ８＾＋ＣＴＬ介导的细胞免疫反应为主的肿瘤疫苗研究进展迅速,提示癌基因抗原肽疫苗有望应用于肿瘤特异性免疫治疗。     

基于肿瘤新生抗原的个体化癌症疫苗治疗的研究进展

恶性肿瘤是目前威胁人类健康的重要病因之一。近年来,肿瘤新生抗原成为了肿瘤免疫治疗的一个新的研究方向,为恶性肿瘤的精准治疗带来了新的希望,本文着重于对基于肿瘤新生抗原的个体化疫苗的研究进展进行综述。     

热休克蛋白—肽复合物肿瘤疫苗

近年发现，肿瘤组织中的热休克蛋白－肽复合物含有多种肿瘤相关肽，可在体内诱导多个肿瘤特异ＣＴＬ克隆，特异杀伤肿瘤细胞，这种作用在同种间不受ＭＨＣ Ｉ类抗原限制，具有良好的临床应用前景，本文综述了这一领域的研究现状。     

肿瘤的HLA相关生物治疗

人类白细胞抗原(HLA)作为人类最复杂、最具多态性的遗传系统,其功能涉及到机体免疫的各个方面,肿瘤的发生发展和HLA有非常重要的关系,因此HLA相关的肿瘤生物治疗成为近年来肿瘤研究的热点,包括发现和鉴定某HLA基因型匹配的、CD8+T细胞所识别的肿瘤特异性抗原肽,寻找CD4+T细胞所识别的抗原肽,针对HLA表型缺失的不同原因而采取的各种HLA基因治疗,以及对HLA分子表达异质性和动态性等的研究,各项研究的进展将为肿瘤的免疫基因治疗提供更科学的理论依据.     

HLA分型在胃肠肿瘤患者中的分布

目前,我室开展MAGE,CEA肽类联合DC细胞治疗消化道肿瘤的研究.MAGE,CEA作为一种抗原肽需要特定的人类白细胞抗原(HLA)分子相结合,才能被DC细胞所递呈.因此需要对病人进行HLA测定,筛选出与MAGE,CEA相匹配的HLA分型的患者.在实验以血清学分型,采用国际上标准的淋巴细胞毒实验.标本取自1998.6～1999.5入我院腹科治疗的部分病人的外周血,共50例,其中HLA-A2,A24,A11及三者的组合共35例,胃癌26例,肠癌9例.结果:     

Heat shock protein 105 peptide vaccine could induce antitumor immune reactions in a phase I clinical trial

Heat shock protein 105 (HSP105) is overexpressed in many cancers, including colorectal cancer (CRC) and esophageal cancer (EC). We carried out a phase I clinical trial of HLA‐A24‐ and HLA‐A2‐restricted HSP105 peptide vaccines in patients with CRC or EC. In this additional study of the trial, we examined the immunological efficacy of the novel vaccine. Thirty patients with advanced CRC or EC underwent HSP105 peptide vaccination. Immunological responses were evaluated by ex vivo and in vitro γ‐interferon enzyme‐linked immunospot assays and their correlation with patients’ prognosis was analyzed. The HSP105 peptide vaccines induced peptide‐specific CTLs in 15 of 30 patients. Among HLA‐A24 patients (n = 15), 7 showed induction of CTLs only ex vivo, whereas among HLA‐A2 patients (n = 15), 4 showed the induction ex vivo and 6 in vitro. Heat shock protein 105‐specific CTL induction correlated with suppression of cancer progression and was revealed as a potential predictive biomarker for progression‐free survival (P = .008; hazard ratio = 3.03; 95% confidence interval, 1.34‐6.85) and overall survival (P = .025; hazard ratio = 2.72; 95% confidence interval, 1.13‐6.52). Production of cytokines by HSP105 peptide‐specific CTLs was observed at the injection sites (skin) and tumor tissues, suggesting that HSP105‐specific CTLs not only accumulated at vaccination sites but also infiltrated tumors. Furthermore, we established 2 HSP105 peptide‐specific CTL clones, which showed HSP105‐specific cytokine secretion and cytotoxicity. Our results suggest that the HSP105 peptide vaccine could induce immunological effects in cancer patients and improve their prognosis.     

Human papillomavirus type 16 E6 variants and HLA class II alleles among Japanese women with cervical cancer

The enhanced oncogenicity of particular human papillomavirus type 16 (HPV16) E6 variants is population-dependent, implying the involvement of additional genetic cofactors. This study was designed to investigate the association between E6 variants and human leukocyte antigen (HLA) polymorphism within a Japanese population. Fifty-seven women with HPV16-positive cervical cancer were analyzed for E6 sequence variation and its relationship to HLA class II alleles. Compared with local controls (n = 138) and published controls (n = 916), DRB1*1501 and DQB1*0602 frequencies were significantly increased among patients with HPV16 E6 prototype (n = 11). Additionally, DRB1*1502 was positively associated with a particular E6 variant designated D25E (n = 25), although we could not find a significant association between HLA class II alleles and L83V variants (n = 16). Our observations suggest that a specific match between E6 variant proteins and HLA types may contribute to HPV16-related cervical carcinogenesis.     

Phase I study of a new cancer vaccine of ten mixed peptides for advanced cancer patients

A phase I study of a new cancer vaccine (KRM‐10), consisting of a mixture of 10 different short peptides, was conducted for patients with advanced gastrointestinal cancers. Primary or secondary endpoints included the dose‐limiting toxicity (DLT), or safety and immune responses, respectively. Peptide‐specific cytotoxic T lymphocytes (CTL) and immunoglobulin G (IgG), together with soluble inflammatory factors, were measured before and after vaccination. Twenty‐one patients were vaccinated with KRM‐10 at dose levels of 10 (n = 6), 20 (n = 8) or 30 mg (n = 7) of peptides every week for 6 weeks. No DLT were observed in the dose range evaluated. Common treatment‐related adverse events were a grade 1 injection site reaction in 15 patients, and fever in three patients (grade 1 in two patients and grade 2 in one patient). CTL activity to at least one peptide at the time of the third and sixth vaccination increased in 2 and 3 of 6 (10 mg), 2 of 8 and 4 of 6 (20 mg), or 2 and 1 of 6 (30 mg) patients, respectively. IgG levels, at the third and sixth vaccination, were also increased in 1 and 1 of 6 (10 mg), 2 of 8 and 4 of 6 (20 mg), or 1 and 3 of 6 (30 mg) patients, respectively. The KRM‐10 vaccine consisting of 20 mg of peptides was determined as the optimal dose for a coming phase II trial because of its safety, and also for demonstrating the most potent activity for augmenting the immune response of the three doses tested. This trial was registered at the UMIN Clinical Trials Registry as UMIN000008820.     

预防性 HPV 疫苗的临床应用进展及思考

宫颈癌是女性生殖系统最常见的恶性肿瘤,并且高危型人乳头瘤病毒（human papillomavirus, HPV）持续感染与宫颈癌的密切关系已经得到流行病学及临床研究证实。因此,HPV 疫苗在预防 HPV 持续感染及宫颈相关病变等方面备受瞩目。本文对目前美国 FDA 批准上市的3种预防性疫苗的临床应用进展进行综述,同时列举出一些尚存在争议的问题,旨在引起人们的重视及共同思考。     

Clinical significance of HLA class I heavy chain expression in patients with gastric cancer

BACKGROUND: Little is known about the relation between HLA-I expression and the prognosis of patients with gastric cancer. The aim of this retrospective study was to clarify the clinical significance of HLA-I heavy chain expression in gastric cancer. METHODS: The study subjects were 202 patients with gastric cancer who had undergone curative surgery. Tumors were examined for expression of HLA-I heavy chain antigens by immunohistochemistry. We analyzed the association of HLA-I heavy chain expression with clinicopathological parameters and patient prognosis. RESULTS: HLA-B/C expression showed association with deeper tumor invasion, higher incidence of lymph node metastasis, more advanced tumor stage, and higher incidence of recurrence. Patients with positive HLA-B/C expression had shorter 5-year overall and 5-year disease-free survival compared with patients whose tumors showed mixed and negative expression (P < 0.05 and 0.01, respectively). In multivariate analysis, although HLA-B/C expression was not recognized as an independent prognostic factor, it was an independent factor in predicting peritoneal recurrence after curative surgery in patients with gastric cancer [relative risk (RR): 9.924, P = 0.003]. CONCLUSION: Expression of HLA-B/C heavy chain is associated with tumor progression, and it could be a significant predictor of peritoneal recurrence after curative surgery in patients with gastric cancer.     

Selected class I and class II HLA alleles and haplotypes and risk of high-grade cervical intraepithelial neoplasia

Human leukocyte antigens (HLAs) present foreign antigens to the immune system and may be important determinants of cervical neoplasia. Previously published associations between HLA and cervical neoplasia exhibit considerable variation in findings. The biomarkers of cervical cancer risk (BCCR) case-control study addressed the role of specific HLA alleles as cofactors in the development of high-grade cervical intraepithelial neoplasia (HG-CIN) based on the most consistent evidence from published literature. Cases (N = 381) were women with histologically-confirmed HG-CIN attending colposcopy clinics and controls (N = 884) were women from outpatient clinics with normal cytological screening smears. Subjects were mainly of French-Canadian descent. Cervical specimens were tested for human papillomavirus (HPV) DNA and HLA genotypes by PGMY L1 consensus primer PCR and a PCR sequence-specific primer method, respectively. Unlike other studies, the DQB1*03 and DRB1*13 allele groups were not associated with risk of HG-CIN. The B7-DRB1*1501-DQB1*0602 haplotype was associated with a 41% overall reduction in HG-CIN risk (odds ratio [OR] = 0.59; 95% confidence interval [CI]: 0.36-0.96), and an 83% reduction in risk of HG-CIN among HPV 16 or HPV 18-positive subjects (OR = 0.17; 95%CI: 0.05-0.54). Paradoxically, however, the same haplotype was associated with HPV 16/18 infection risk among controls (OR = 8.44, 95%CI: 1.12-63.73). In conclusion, the B7-DRB1*1501-DQB1*0602 haplotype was protective against HG-CIN, especially in individuals infected with oncogenic HPV, but the mechanism of the association seems to involve multiple steps in the natural history of HPV and CIN.     

乳腺癌疫苗研究面临的机遇和挑战

免疫治疗作为一种极具发展前景的治疗方式给乳腺癌的治疗带来了新的希望。近年来,关于乳腺癌疫苗的研究已陆续开展,将这些研究成果合理、快速地用于临床,为乳腺癌的免疫治疗提供了机遇与挑战。本文重点阐述乳腺癌治疗性疫苗的一些设计策略、临床应用情况,以及未来乳腺癌疫苗研究的发展和应用趋势。随着对肿瘤特异性免疫应答的深入了解、肿瘤特异性抗原的不断发现和鉴定,以及对肿瘤微环境的深入认识,乳腺癌疫苗的研发水平必将得到进一步提高,更好地服务于临床。     

Epitope selection and development of peptide based vaccines to treat cancer

Cytotoxic T lymphocytes recognize peptides that associate with class I major histocompatibility complex molecules. Since cytotoxic T cells have the capacity to recognize and destroy tumor cells, identification of epitopes recognized by these cells in tumor-associated antigens would allow the production of compounds for the treatment of cancer. Here we review some of the approaches being explored to identify tumor-associated antigens and to develop peptide-based vaccines that induce cytotoxic T lymphocytes against specific tumors.     

A phase I trial of cytotoxic T-lymphocyte precursor-oriented peptide vaccines for colorectal carcinoma patients

In most protocols of peptide-based vaccination, no consideration has been paid to whether or not peptide-specific cytotoxic T-lymphocyte (CTL) precursors are pre-existent in cancer patients. Initiation of immune boosting through vaccination is better than that of immune priming to induce prompt and strong immunity. In this study, 10 human histocompatibility leukocyte antigen-A24(+) patients with advanced colorectal carcinomas were treated with up to four peptides that had been positive for pre-vaccination measurement of peptide-specific CTL precursors in the circulation (CTL precursor-oriented peptide vaccine). No severe adverse effect was observed, although local pain and fever of grade I or II were observed. Post-vaccination peripheral blood mononuclear cells (PBMCs) from five patients demonstrated an increased peptide-specific immune response to the peptides. Increased CTL response to cancer cells was detected in post-vaccination PBMCs of five patients. Antipeptide immunoglobulin G became detectable in post-vaccination sera of seven patients. Three patients developed a positive delayed-type hypersensitivity response to at least one of the peptides administrated. One patient was found to have a partial response; another had a stable disease, sustained through 6 months. These results encourage further development of CTL precursor-oriented vaccine for colorectal cancer patients.