The connection of innate and adaptive anti-cancer immunity

IFN-α是一种多效性细胞因子，具有免疫调节特性，可提高治疗性癌症疫苗的功效。本研究的目的是评估重组IFN-α与痘病毒疫苗结合靶向人癌胚抗原（CEA）在结肠直肠癌和胰腺腺癌的小鼠模型中的有效性和相容性，其中CEA是自身抗原。在无肿瘤小鼠的引流腹股沟淋巴结中评价IFN-α的表型和功能作用。我们研究了IFN-α给药部位（局部与远端）对痘病毒疫苗接种的抗原特异性免疫应答的影响。进行机制研究以评估IFN-α和CEA定向的痘病毒疫苗在荷瘤CEA转基因小鼠中的功效。我们确定了IFN-α的剂量和时间表，诱导引流腹股沟淋巴结的局部扩张，并改善细胞毒性（自然杀伤细胞和CD 8+）和抗原呈递。通过在接种部位远端给予IFN-α避免了对牛痘病毒的抑制。IFN-α和疫苗的组合抑制肿瘤生长，提高存活率，并在患有CEA+腺癌的小鼠中引起CEA特异性CTL应答。在患有胰腺肿瘤的小鼠中，IFN-α减缓肿瘤生长，诱导CTL活性，并增加CD 8+肿瘤浸润淋巴细胞。这些数据表明，IFN-α可用作抗原导向痘病毒疫苗的生物应答调节剂，以产生显著的治疗性抗肿瘤免疫应答。这项研究提供了基本原理和机制的见解，以支持这种免疫策略在CEA表达癌患者中的临床试验。 在另一项研究中，将（51）Cr-预标记的结肠癌细胞（模拟循环肿瘤细胞（CTC））添加到人外周血中，并暴露于星形孢菌素（ST）以增加癌胚抗原（CEA）表达。用Ber-EP 4单克隆抗体包被的免疫磁珠捕获CTC，识别大多数上皮来源的癌细胞中存在的共同上皮抗原，捕获效率超过80%。此外，ST处理增加CEA表达而不损害Ber-EP 4捕获效率。在对37名患者的初步临床研究中，使用Ber-EP 4珠捕获CTC，并通过用于CEA或细胞角蛋白-19（CK）mRNA检测的RT-PCR组识别CTC。结果表明：（a）CEA阳性CTC的百分比（CTC（CEA），54.1%）低于CK阳性CTC的百分比（CTC（CK），70.3%）;（B）体外ST治疗将大量CTC（CEA）阴性转化为CTC（CEA）阳性病例。因此，免疫磁性捕获结合暴露于ST提供了一种可行且灵敏的技术，用于检测响应ST介导的CEA上调的功能活性CTC。

IFN-alpha is a pleiotropic cytokine possessing immunomodulatory properties that may improve the efficacy of therapeutic cancer vaccines. The aim of this study was to evaluate the effectiveness and compatibility of combining recombinant IFN-alpha with poxvirus vaccines targeting the human carcinoembryonic antigen (CEA) in murine models of colorectal and pancreatic adenocarcinomas, where CEA is a self-antigen. The phenotypic and functional effects of IFN-alpha were evaluated in the draining inguinal lymph nodes of tumor-free mice. We studied the effect of the site of IFN-alpha administration (local versus distal) on antigen-specific immune responses to poxvirus vaccination. Mechanistic studies were conducted to assess the efficacy of IFN-alpha and CEA-directed poxvirus vaccines in tumor-bearing CEA transgenic mice. We identified a dose and schedule of IFN-alpha that induced a locoregional expansion of the draining inguinal lymph nodes and improved cellular cytotoxicity (natural killer and CD8+) and antigen presentation. Suppression of the vaccinia virus was avoided by administering IFN-alpha distal to the site of vaccination. The combination of IFN-alpha and vaccine inhibited tumor growth, improved survival, and elicited CEA-specific CTL responses in mice with CEA+ adenocarcinomas. In mice with pancreatic tumors, IFN-alpha slowed tumor growth, induced CTL activity, and increased CD8+ tumor-infiltrating lymphocytes. These data suggest that IFN-alpha can be used as a biological response modifier with antigen-directed poxvirus vaccines to yield significant therapeutic antitumor immune responses. This study provides the rationale and mechanistic insights to support a clinical trial of this immunotherapeutic strategy in patients with CEA-expressing carcinomas. In another study, (51)Cr-prelabeled colon cancer cells (simulating circulating tumor cells (CTCs)) were added to human peripheral blood and exposed to staurosporine (ST) to increase carcinoembryonic antigen (CEA) expression. CTCs were captured with immunomagnetic beads coated with Ber-EP4 monoclonal antibody, recognizing the common epithelial antigen present in the majority of cancer cells of epithelial origin, with capture efficiency of more than 80%. Moreover, ST treatment increased CEA expression without compromising Ber-EP4 capture efficiency. In a pilot clinical study on 37 patients, CTCs were captured using Ber-EP4 beads, and recognized by RT-PCR set for CEA or cytokeratin-19 (CK) mRNA detection. The results showed that: (a) the percentage of CEA-positive CTCs (CTC(CEA), 54.1%) was lower than that of CK-positive CTCs (CTC(CK), 70.3%); (b) in vitro ST treatment converted a significant number of CTC(CEA)-negative into CTC(CEA)-positive cases. Therefore, immunomagnetic capture combined with exposure to ST provides a feasible and sensitive technique for the detection of functionally-active CTCs responsive to ST-mediated CEA up-regulation.