细胞及疫苗免疫疗法在多发性骨髓瘤中的研究进展

异基因造血干细胞移植和供者淋巴细胞输注能诱导多发性骨髓瘤（MM）患者的移植物抗骨髓瘤免疫效应，从而使患者获得长期生存，但其疗效的局限性和相关毒性限制了其在临床上的广泛应用。因此，目前正在寻求更有效的细胞免疫疗法和疫苗疗法，以诱导更特异、更稳定和更有效的抗骨髓瘤免疫应答反应，同时降低治疗相关的风险。随着分子生物学、基础免疫学和应用免疫学的发展，催生了一系列极具前景的MM治疗方法，如抗原特异性的嵌合受体和骨髓瘤特异性表位的靶向T细胞受体等修饰T细胞、疫苗致敏并体外扩增自体T细胞、扩增骨髓浸润的淋巴细胞及浆细胞、树突状细胞融合疫苗等。这些新兴的治疗方案与免疫调节制剂、程序性死亡受体1（PD-1）T细胞调节通路抑制剂结合，有望改善MM患者的治疗效果。介绍第58届美国血液学会（ASH）年会报道的关于细胞和疫苗免疫疗法在MM治疗中的相关信息，并探讨了将这些疗法与现有的治疗方案整合治疗MM的可行性。

Effects of dendritic cells from cord blood CD34^+ cells on human hepatocarcinoma cell line BEL-7402 in vitro and in SCID mice

AIM: To develop a cancer vaccine of dendritic cells derived from human cord blood CD34+ cells and to investigate its cytotoxicity on human hepatocarcinoma cells in vitro and in sever combined immunodeficiency (SCID) mice. METHODS: Lymphocytes from cord blood or peripheral blood were primed by DCs, which were derived from cord blood and pulsed with whole tumor cell lysates. Nonradiative neutral red uptake assay was adopted to detect the cytotoxicity of primed lymphocytes on human hepatocartinoma cell line BEL-7402 in vitro. The anti-tumor effect of primed lymphocytes in vivo was detected in SCID mice, including therapeutic effect and vaccination effect. RESULTS: The cytotoxicity of DC vaccine primed lymphocytes from cord blood or peripheral blood on human hepatocarcinoma cell line BEL-7402 was significantly higher than that of unprimed lymphocytes in vitro (44.09% vs 14.69%, 47.92% vs 19.44%, P<0.01). There was no significant difference between the cytotoxicity of primed lymphocytes from cord blood and peripheral blood (P>0.05). The tumor growth rate and tumor size were smaller in SCID mice treated or vaccinated with primed lymphocytes than those with unprimed lymphocytes. SCID mice vaccinated with primed lymphocytes had a lower tumor incidence (80% vs 100%, P<0.05) and delayed tumor latent period compared with mice vaccinated with unprimed lymphocytes (11d vs 7 d,P<0.01). CONCLUSION: Vaccine of cord blood derived-DCs has an inhibitory activity on growth of human hepatocarcinoma cells in vitro and in SCID mice. The results also implicate the potential role of cord blood derived-DC vaccine in clinical tumor immunotherapy.

Induction of protective antitumor activity of tumor lysate-pulsed dendritic cells vaccine in RM-1 prostate cancer model

Objective： To investigate the antitumor activity of tumor lysate-pulsed dendritic cells vaccine in RM-1 prostate cancer mice model with the survival time of mice calculated and the tumor size measured in DC vaccine therapy. Methods： C57BL/6 mice were immunized on the dorsal flank by s.c. inoculation of Lysate-DC, ova-DC, and non-DC on day -7. On day 0, 2× 10^6cells of RM-1 tumor cells （H-2b） were injected s.c. in C57BL/6 mice pre-treated by s.c. inoculation of modified DCs, correspondingly. DTH assay was performed with modified DCs. In partial test, for the determination of which immune cells were required for antitumor activity, mice were immunodepleted of CD4, CDS, or natural killer （NK） NK1.1 cells with the corresponding monoclonal antibodies. The survival time of nude mice loaded with tumor cells was calculated and the size of tumor measured. Results： In RM-1 mice prostate cancer model, immunized with lysate-DC, compared with ova-DC and non-DC, the pre-infection vaccine resulted in 100% clearance of primary tumors, whereas on day 0 of injection vaccine cleared 40-60% of primary tumors. On day 0, C57BL/6 mice （H-2b） were immunized with Lysate-DC, compared with ova-DC and non-DC by caudal vein injection, then on day 15, RM-1 cells were inoculated. On day 30, average diameters of tumor in different groups of modified DC were 23.7±5.4 mm, 22.1±4.9 mm, 4.3±2.6 mm, respectively. Lysate-DC, compared with ova-DC and non-DC, can greatly depressed RM-1 tumor cell growth （P〈0.01）. The mean survival time of C57BL/6 mice in Lysate-DC, ova-DC and non-DC groups were 15.8±2.6, 16.6±3.2, 39.0±5.6, respectively, and there was a significant difference in the mean survival time in lysate-DC group between ova-DC and non-DC group （P〈0.01）. DTH test showed that lysate-DC could prime T lymphocyte and elicit tumor antigen specific immune response, and over 80% mice in groups of lysate-DC showed obvious swelling in their foot pad. This response was strengthened with repeating inoculation, whereas DTH response was not seen in control group. In vivo depletion of NK cells resulted in a 40-60% reduction in growth suppression within the primary tumor, and depletion of CD4^＋ cells resulted in a 20% reduction in growth suppression. Conclusion： The minor lysate-pulsed dendritic cells vaccine could elicit antitumor activity in RM-1 loaded C57BL/6 mice, and prolong the duration of RM-1 loaded C57BL/6 mice. So DC-based immunotherapy with hormone-refractory prostate carcinoma yielded protective immunity, generated efficient cellular antitumor responses, thereby providing further preclinical support for feasible immunotherapy approaches for prostate cancer.

HEAT SHOCK PROTEIN gp96 AND CANCER IMMUNOTHERAPY

Heat shock protein gp96 is a highly conserved and monomorphic glycoprotein in the endoplasmic reticulum.It functions as molecular chaperone and can associate with a variety of antigenic peptides noncovalently in vivo and in vitro. Recent studies have indicated that gp96 molecules participate in major histocompatibility complex class I - restricted antigen presentation pathway. Immunization of mice with gp96 preparations isolated from cancer cells can elicit a cancer - specific protective T cell immune response that is recallable, which is a prerequisite for gp96 as a therapeutic vaccine against cancers. The immunogenicity of gp96 molecules has been attributed to the antigenic peptides associated with them. These phenomena provide a new pathway for cancer immunotherapy. The mechanism that the gp96 -peptide complex induces specific immune response and the explorations for gp96 - peptide complex as a therapeutic cancer vaccine are reviewed.