The connection of innate and adaptive anti-cancer immunity

干扰素-α是一种多效性细胞因子，具有免疫调节作用，可提高治疗性肿瘤疫苗的疗效。本研究的目的是评价重组干扰素-α与针对人癌胚抗原(CEA)的痘病毒疫苗在以CEA为自身抗原的结直肠癌和胰腺癌小鼠模型中的有效性和相容性。在无瘤小鼠的腹股沟引流淋巴结中评价干扰素-α的表型和功能效应。我们研究了干扰素-α注射部位(局部和远端)对痘病毒疫苗抗原特异性免疫反应的影响。机制研究是评估干扰素-α和CEA导向的痘病毒疫苗在荷瘤CEA转基因小鼠中的效果。我们确定了干扰素-α的剂量和方案，该剂量和方案可以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CD8+)和抗原呈递。通过在接种部位远端注射干扰素-α可以避免对痘苗病毒的抑制。干扰素-α和疫苗的联合应用抑制了CEA+腺癌小鼠的肿瘤生长，提高了存活率，并激发了CEA特异性CTL反应。在胰腺肿瘤的小鼠中，干扰素-α减缓了肿瘤的生长，诱导了CTL活性，并增加了CD8+肿瘤浸润性淋巴细胞。这些数据表明，干扰素-α可以作为一种生物反应调节剂与抗原导向的痘病毒疫苗一起产生显著的治疗性抗肿瘤免疫反应。这项研究提供了理论基础和机制见解，支持在CEA表达的癌症患者中进行这种免疫治疗策略的临床试验。在另一项研究中，将(51)铬预先标记的结肠癌细胞(模拟循环肿瘤细胞(CTCs))添加到人外周血中，并暴露于星形孢子素(ST)以增加癌胚抗原(CEA)的表达。用包被Ber-Ep4单抗的免疫磁珠捕获CTCs，识别大多数上皮源性癌细胞中存在的共同上皮抗原，捕获率超过80%。此外，ST处理在不影响Ber-Ep4捕获效率的情况下增加了CEA的表达。在一项针对37名患者的初步临床研究中，用Ber-Ep4珠子捕获CTCs，并通过RT-PCR检测CEA或细胞角蛋白-19(CK)mRNA来识别CTCs。结果表明：(A)CTC(CEA)阳性CTC(54.1%)低于CK(CTC(CK))阳性CTC(70.3%)；(B)体外ST可将CTC(CEA)阴性CTC转化为CTC(CEA)阳性。因此，免疫磁捕获结合ST暴露为检测ST介导的CEA上调的功能活性CTCs提供了一种可行和灵敏的技术。

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.