Okawaki Makoto, Yamaguchi Yoshiyuki, Okita Riki, Ohara Masahiro, Okada Morihito
Department of Surgical Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-hu, Hiroshima 734-8551, Japan.
Hiroshima J Med Sci. 2008 Mar;57(1):37-46.
Effects of low-dose anti-CD25 antibody on targeting regulatory T (Treg) cells in vitro and in vivo were investigated. Human-mouse chimeric anti-CD25 monoclonal antibody basiliximab was administered into the effusion cavity, followed by locoregional immunotherapy using OK-432 on day 7. Peripheral blood mononuclear cells and effusion lymphocytes (ELs) were collected before and after the basiliximab administration and subjected to further investigations. Surface phenotypes, IFN-gamma production, cytotoxic activity and foxp3 expression of ELs were assessed by flow cytometry, ELISA, 51Cr-releasing assay, and RT-PCR analysis, respectively. We observed that a low concentration of 0.01 microg/ml basiliximab effectively targeted CD4+CD25(bri) Treg cells while preserving CD4+CD25(dim) activated T cells in vitro. This concentration of basiliximab significantly augmented interferon (IFN)-gamma production of ELs when interleukin (IL)-2 was added on day 0 or on day 1 after basiliximab. In the clinical study, intracavitary administration of basiliximab on day 0 followed by OK-432 on day 7 was as safe, well-tolerated, and effective as using OK-432 alone, and a low-dose of 0.002-0.005 mg/kg basiliximab could target CD4+CD25(bri) cells for at least 3 days while relatively preserving CD4+CD25(dim) cells. Foxp3 expression of ELs was not changed definitely by the intracavitary basiliximab. These results suggest that low-dose basiliximab can target Treg cells in vitro and in vivo, and subsequently augment the activation of ELs. Locoregional immunotherapy of malignant effusion using the Treg cell-conditioning regimen with low-dose basiliximab followed by OK-432 administration on day 0 or on day 1 should be evaluated for clinical efficacy in the next phase II trial.
研究了低剂量抗CD25抗体在体外和体内对调节性T（Treg）细胞的靶向作用。将人鼠嵌合抗CD25单克隆抗体巴利昔单抗注入体腔，然后在第7天使用OK-432进行局部区域免疫治疗。在巴利昔单抗给药前后收集外周血单核细胞和体腔积液淋巴细胞（ELs），并进行进一步研究。分别通过流式细胞术、酶联免疫吸附测定、51Cr释放试验和逆转录-聚合酶链反应分析评估ELs的表面表型、γ干扰素产生、细胞毒性活性和叉头框蛋白3（Foxp3）表达。我们观察到，低浓度（0.01μg/ml）的巴利昔单抗在体外可有效靶向CD4+CD25（高表达）Treg细胞，同时保留CD4+CD25（低表达）活化T细胞。当在巴利昔单抗给药后第0天或第1天添加白细胞介素（IL）-2时，该浓度的巴利昔单抗可显著增强ELs的γ干扰素产生。在临床研究中，第0天腔内注射巴利昔单抗，随后第7天使用OK-432，与单独使用OK-432一样安全、耐受性良好且有效，低剂量（0.002-¬0.005mg/kg）的巴利昔单抗可靶向CD4+CD25（高表达）细胞至少3天，同时相对保留CD4+CD25（低表达）细胞。腔内注射巴利昔单抗未明确改变ELs的Foxp3表达。这些结果表明，低剂量巴利昔单抗可在体外和体内靶向Treg细胞，随后增强ELs的活化。在下一阶段的II期试验中，应评估采用低剂量巴利昔单抗预处理Treg细胞，随后在第0天或第1天给予OK-432进行恶性积液局部区域免疫治疗的临床疗效。
