Induction of immune tolerance toward tumor-associated-antigens enables growth of human hepatoma in mice.

Adoptive transfer of immunity against hepatitis B surface antigen (HBsAg) was previously shown to facilitate suppression of experimental human hepatocellular carcinoma (HCC) expressing HBsAg in athymic mice. We have shown that oral tolerance induces antigen‐specific immune suppression of HBsAg by feeding hepatitis B virus (HBV) antigens. In the present study we evaluated the effect of oral tolerance induction toward HBV or HCC antigens on the growth of experimental HCC‐expressing HBsAg in mice. Tolerance induction was induced in mice by 5 oral feedings of 1 μg HBV antigens or HCC‐extracted proteins (50 μg protein) before vaccination with recombinant HBsAg. Splenocytes (2 × 10⁶) from these mice were transferred to sublethally irradiated athymic BALB/c mice previously transplanted subcutaneously with 10⁷ human hepatoma Hep3B cells. Adoptive transfer of splenocytes immunized toward HBsAg prevented tumor growth. At 4 weeks after splenocyte transplantation, tumor volume and serum alpha‐fetoprotein (AFP) levels in athymic mice transplanted with splenocytes immunized to HBsAg were undetectable as compared with 1,048 ± 738 mm³ and 2,500 ± 1,431 ng/ml in recipients of naïve splenocytes (p < 0.0001). Mice receiving splenocytes tolerized toward Hep3B cells, as manifested by reduced serum HBs antibody levels, reduced HBV‐specific stimulation index and reduced HBV‐specific‐IFNγ spot‐forming cells, had early tumor growth evident by elevated AFP serum levels, weight loss and mortality, which were suppressed at 6 weeks. Mice transplanted with splenocytes tolerized toward HBV antigens did not have direct evidence of tumor growth. Induction of oral tolerance toward HCC‐extracted proteins enabled transient tumor growth in this model. This effect was mediated through downregulation of the anti‐HBV immune response. © 2002 Wiley‐Liss, Inc.     

NKT and CD8 lymphocytes mediate suppression of hepatocellular carcinoma growth via tumor antigen-pulsed dendritic cells

Dendritic cells (DCs) are antigen presenting cells that play a role in T-cell activation. Liver-associated natural killer T lymphocytes (NKTs) are a unique subset of lymphocytes that may be important in antitumor immunity. Hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) expresses hepatitis B virus surface antigen (HBsAg) on its cell surface and may serve as a tumor-associated antigen. The aim of the study was to evaluate the antitumor effect of DC pulsed with tumor or viral-associated antigens in HBV-expressing HCC in mice and to determine the role of NKT lymphocytes in this process. Balb/c mice were sublethally irradiated and transplanted with Hep3b HCC cell line, followed by transplantation of naive splenocytes. DCs were separated using CD11c beads and pulsed with HBV-enveloped proteins (group A), HCC cell lysate (group B), or BSA (control group C). Mice were followed for survival and tumor size. To determine the mechanism of the antitumor effect, intrasplenic and intrahepatic lymphocyte subpopulations were analyzed by FACS for NKT, CD4 and CD8 markers. Tumor-associated antigens-specific IFNgamma ELISPOT, T-cell proliferation assays and serum cytokine analysis were performed. Treatment with tumor-associated antigen-pulsed DC significantly improved survival (40% and 50% as compared with 0% in groups A, B, and control group C, respectively; p < 0.005). Tumor size decreased to 12.8 +/- 0.4 and 0 from 60.4 +/- 0.9 mm(3) in groups A, B, and control group C, respectively (p < 0.005). Adoptive transfer of HBV or Hep3b-associated antigens-pulsed DC induced a 6-fold increase in peripheral CD8(+) lymphocytes (from 1% in control mice to 6% and 5.5% in groups A and B, respectively), along with a decrease in CD4(+) lymphocytes (from 3.5% in controls to 1.4% and 2.3% in A and B, respectively; p < 0.005). The CD8(+)/CD4(+) ratio increased from 0.28 in controls to 4.28 and 2.39 in groups A and B, respectively (p < 0.005). Intrasplenic NKT cells increased from 7% in control mice to 7.98% and 14.6% in groups A and B, respectively. In contrast, an opposite shift was observed inside the liver. Intrahepatic lymphocyte analysis showed a marked increase in CD4(+) and a decrease in CD8(+) lymphocytes in treated groups. The intrahepatic CD4(+) number increased from 0.5% in controls to 2.15% and 25.8% in groups A and B, respectively (p < 0.005). In contrast, a significant decrease in the intrahepatic CD8(+) numbers was observed (from 7% in controls to 1.0% and 2.4% in groups A and B, respectively; p < 0.005). A significant increase was noted in HBV-specific IFNgamma spot-forming T-cell colonies from 0.0 to 8.8 +/- 1.7 and 1.8 +/- 2.9 in groups C, A, and B, respectively (p < 0.005). Similarly, a significant increase in the HBV-specific T-cell stimulation index, from 0.8 +/- 0.2 to 7.2 +/- 0.4, in groups C and B, respectively, was noted (p < 0.002). IFNgamma and IL12 serum levels increased significantly in treated groups. IFNgamma and IL12 serum levels increased to 380 +/- 30 and 400 +/- 20, and 960 +/- 40 and 760 +/- 60 in groups A and B, compared with 150 +/- 16 and 490 +/- 40 pg/ml in control mice (p < 0.005). Tumor antigen-pulsed DCs effectively suppressed the growth of hepatocellular carcinoma in mice. This effect was associated with enhanced NKT and CD8(+) lymphocyte function and augmentation of the antitumor/antiviral-specific IFNgamma production.     

Associations Between Infiltrating Lymphocyte Subsets and Hepatocellular Carcinoma

Aims: We aimed to analyze the phenotype of tumor-infiltrating lymphocytes (TILs) and non-tumor infiltrating lymphocytes (NILs) in HCC and non-tumor tissues, and evaluate relationships between changes in these cells and the prognosis of HCC. Methods: Lymphocytes were isolated from HCC and corresponding non-tumor tissues and tested by flow cytometry. For comparison, clinical parameters were analyzed. Results: Compared with the non-tumor tissue, tumor tissue had a lower intensity of NK, NKT andCD8+T cell infiltration. TILs had higher intensity of CD4+CD25+Foxp3+regulatory T cell (Treg cells) infiltration compared with that in NILs. The prevalence of Treg cells was associated with fewer CD8 + T lymphocytes in the HCC immune microenvironment. The frequencies of NK cells and CD8+T cells in TILs of HCC patients with metastasis less than 12 months were lower than those without metastasis. However, the frequency of Treg cells was higher than those without metastasis. Conclusion: These results suggest that the frequencies of CD8+T, NK and NKT cells as well as Treg cells in the tumor tissue of HCC are significantly associated with patient survival, and could be applied as predictive indicators for HCC prognosis.     

Evolution of expression of hepatitis B surface and core antigens (HBsAg, HBcAg) in resected primary and recurrent hepatocellular carcinoma in HBsAg carriers in Taiwan. Correlation with local host immune response

Studies were conducted on the evolution of hepatitis B virus (HBV) surface and core antigens (HBsAg and HBcAg) in the tumors of both primary and recurrent hepatocellular carcinoma (HCC) in 27 HBsAg carriers; these were followed for up to 8 years after the resection of the primary tumor. Twenty-seven primary and 34 recurrent tumors were included. HBV antigens were detected in the tumor of the primary HCC in ten cases (37%): six (22.2%) had both antigens (Group I) and four (14.8%) had HBsAg alone (Group II). The remaining 17 cases were negative for both antigens (Group III). Intrahepatic tumor recurrence occurred in 17 cases; both HBcAg and HBsAg were found in the recurrent HCC in four of five HBcAg-positive cases (Group I). In contrast, HBcAg was detected in none of the other 12 cases (Group II, 0 of one; Group III, 0 of 11), and HBsAg in only one (Group II, 0 of one; Group III, one of 11), P less than 0.03 and P less than 0.02, respectively. Groups I, II, and III had extrahepatic recurrence in two, four, and seven cases, respectively. HBcAg was detected in none, while HBsAg was found in only one case (7.7%). The frequent detection of both antigens in the primary HCC and even in the intrahepatic recurrences suggests that HBV replication in HCC may occur more commonly than previously perceived, especially in the small HCC. Failure to detect HBV antigens in the extrahepatic recurrences suggests that the switch-off of the viral gene expression, particularly the core gene, may be an event related to the extrahepatic growth of HCC. HBV antigen expression in HCC is associated with more evident lymphocyte infiltration; this local host immune response may in turn result in a negative selection and expansion of the antigen-negative HCC cell clones. This suggestion is in accord with the fact that HBV antigens, particularly HBcAg, are rarely detected in advanced HCC.     

Unmasking immunosurveillance against a syngeneic colon cancer by elimination of CD4+ NKT regulatory cells and IL-13

We have previously observed a novel role of natural killer T (NKT) cells in negative regulation of antitumor immune responses against an immunogenic regressor tumor expressing a transfected viral antigen. Here, we investigated whether hidden spontaneous antitumor immunosurveillance, in the absence of a vaccine, could be revealed by disruption of this negative regulatory pathway involving CD4+ NKT cells and interleukin-13 (IL-13), in a murine pulmonary metastasis model of a nontransfected, nonregressor, syngeneic tumor, the CT26 colon carcinoma. Lung metastases of CT26 were decreased in CD4+ T cell-depleted BALB/c mice, suggesting that CD4+ T cells were involved in negative regulation of antitumor responses. CD1-knock out (CD1-KO) mice, which have conventional CD4+ T cells and CD4+CD25+ regulatory T cells but lack CD1-restricted CD4+ NKT cells, were significantly resistant to lung metastasis of CT26. The metastases were not further decreased in CD4+ T cell-depleted CD1-KO mice, implying that CD4+ NKT cells might be the primary negative regulator of antitumor immune responses in BALB/c mice. CD8+ T cells were found to act as effectors in antitumor immune responses, since the inhibition of lung metastases observed in naive CD1-KO or CD4+ T cell-depleted mice was abrogated by depletion of CD8+ T cells. Lung metastases were significantly decreased by treatment of mice with an IL-13 inhibitor, but not by deficiency or inhibition of IL-4. Thus, even for a nonregressor tumor, immunosurveillance exists but is negatively regulated via CD4+ NKT cells possibly mediated by IL-13, and can be unmasked by removal of these negative regulatory components.     

Requirement for IFN-gamma, CD8+ T lymphocytes, and NKT cells in talactoferrin-induced inhibition of neu+ tumors

We have previously shown that talactoferrin-alfa (TLF), a recombinant human lactoferrin, is an immunomodulatory protein that is active against implanted tumors, both as a single agent and in combination with chemotherapy. In this study, we show that talactoferrin is active against autochthonous tumors in a transgenic mouse line, which is more analogous to human cancers, and identify key mechanistic steps involved in the anticancer activity of oral TLF. BALB/c mice transgenic for the rat neu (ErbB2) oncogene (BALB-neuT) treated with oral TLF showed a significant delay in carcinogenesis, with 60% tumor protection relative to vehicle-treated mice at week 21. Oral TLF also showed tumor growth inhibition in wild-type BALB/c mice implanted with neu(+) mammary adenocarcinoma, with one third displaying a long-lasting or complete response. Oral TLF induces an increase in intestinal mucosal IFN-gamma production and an increase in Peyer's patch cellularity, including expansion of CD8(+) T lymphocytes and NKT cells, and the enhancement of CD8(+) T-cell cytotoxicity. In IFN-gamma knockout mice, there is an absence of the TLF-induced Peyer's patch cellularity, no expansion of CD8(+) T lymphocytes and NKT cells, and loss of TLF anticancer activity. TLF antitumor activity is also lost in mice depleted of CD8(+) T cells and in CD1 knockout mice, which lack NKT activity. Thus, the inhibition of distant tumors by oral TLF seems to be mediated by an IFN-gamma-dependent enhancement of CD8(+) T- and NKT cell activity initiated within the intestinal mucosa.     

Natural History of Chronic Hepatitis B Virus Infection in Ahvaz City,Iran

Objective: A long persistent of Chronic Hepatitis B (CHB) infection may develop liver cirrhosis or hepatocellularcarcinoma (HCC) and about one million people die due to HBV -related liver cancer and end-stage liver disease annuallyworldwide. The natural history of CHB phases comprises four phases: immune tolerant (HBeAg detectable and ALT(Alanine Transaminase) normal, HBeAg-positive immune active (HBeAg detectable, anti-HBe antibodies undetectableand ALT persistently elevated), HBeAg-negative immune active (HBeAg undetectable, anti-HBe antibodies presentand ALT persistently elevated), inactive carrier (HBeAg undetectable, anti-HBe antibodies present and ALT normal).The evaluation of chronic hepatitis B phases is a crucial to manage the burden of disease and limit the developmentof associated complications, such as cirrhosis and hepatocellular carcinoma (HCC). Thus this study conducted toevaluate the natural history of HBV infection in patients with chronic HBV infection in Ahvaz city, Iran. Methods: Inthis study, 71 non-treated CHB individuals were recruited including 44 (62%) males and 27(38%) females. The serawere tested for HBV markers, HBsAg, HBcIgG, HBeAg, and HBeAb. ALT assay and HBV viral load were carried outfor each CHB individual. Results: Based on the analysis of serological, ALT status and viral load, the results showed:immune tolerance 5(7%), eAg+ Immune Clearance 14(19.7%), eAg- Immune Clearance 29 (40.84%) and InactiveCarrier 23 (32.39%). The HBeAg seroconversion was observed in a male age 18 year. Conclusion: The results ofthe natural history of individuals with chronic hepatitis B phases CHB shows immune tolerance (7%), eAg+ ImmuneClearance (19.7%), eAg- Immune Clearance (40.84%) and Inactive Carrier (32.39%). To prevent the consequence ofCHB infection, an individual in immune tolerance phase should be tested periodically for ALT level, HBV markers,HBsAg, HBcIgG, HBeAg, HBeAb and HBV viral load. Then decision-making therapy can be applied for CHB patientsat early stage of immune clearance.     

Adenovirus-mediated intratumoral expression of immunostimulatory proteins in combination with systemic Treg inactivation induces tumor-destructive immune responses in mouse models

Tumor-associated antigens (TAAs) include overexpressed self-antigens (for example, Her2/neu) and tumor virus antigens (for example, HPV-16 E6/E7). Although in cancer patients, TAA-specific CD4+ and CD8+ cells are often present, they are not able to control tumor growth. In recent studies, it became apparent that tumor site-located immune evasion mechanisms contribute to this phenomenon and that regulatory T cells have a major role. We tested in Her2/neu+ breast cancer and HPV-16 E6/E7+ cervical cancer mouse models, whether intratumoral expression of immunostimulatory proteins (ISPs), for example, recombinant antibodies (αCTLA-4, αCD137, αCD3), cyto/chemokines (IL-15, LIGHT, mda-7) and costimulatory ligands (CD80), through adenovirus(Ad)-mediated gene transfer would overcome resistance. In both the breast and cervical cancer model, none of the Ad.ISP vectors displayed a significant therapeutic effect when compared with an Ad vector that lacked a transgene (Ad.zero). However, the combination of Ad.ISP vectors with systemic T regulatory (Treg) depletion, using anti-CD25?mAb (breast cancer model) or low-dose cyclophosphamide (cervical cancer model) resulted in a significant delay of tumor growth in mice treated with Ad.αCTLA4. In the cervical cancer model, we also demonstrated the induction of a systemic antitumor immune response that was able to delay the growth of distant tumors. Ad.αCTLA4-mediated tumor-destructive immune responses involved NKT and CD8+ T cells. In both models no autoimmune reactions were observed. This study shows that Ad.αCTLA4 in combination with systemic Treg depletion has potentials in the immunotherapy of cancer.     

Immune response of athymic nude mice to papovavirus SV40 tumor-associated antigens.

The requirement of T cell functions in the induction of immune response to SV40-specific transplantation rejection antigen and intranuclear tumor antigen was studied using athymic nude mice. The results obtained indicate that virus-immunized athymic nude mice were unable to reject SV40 tumor cell challenge, and sensitized lymphocytes capable of inhibiting tumor growth in vivo could not be demonstrated in the spleens of virus-immunized mice. Athymic nude mice bearing tumor induced by virus-free SV40-transformed BALB/c cells failed to develop antibodies to intranuclear T antigen. Athymic nude mice also failed to respond to viral antigens. Thus it can be concluded that T cell functions are required in the induction of cellular immune response to SV40-specific transplantation rejection antigen and in humoral immune response to SV40-specific T antigen and virion antigen.     

肝癌小鼠脾脏免疫细胞的变化及其意义

目的:观察小鼠H22细胞原位种植性肝癌模型中,脾脏正性免疫细胞和负性免疫细胞比例的变化,并且观察脾脏切除后外周血和肿瘤组织免疫细胞比例的变化以及对肿瘤生长的影响。方法:建立小鼠H22细胞原位种植性肝癌模型,在荷瘤的不同时期,用流式细胞术检测脾脏中负性免疫细胞（MDSC、Treg）和正性免疫细胞（总CD3+T细胞、CD4+T细胞、CD8+T细胞、NK细胞、NKT细胞）比例的变化。荷瘤1 w后切除脾脏,用流式细胞术检测外周血及肿瘤组织中免疫细胞比例的变化,并比较切脾前后肿瘤重量、腹水量、荷瘤小鼠生存期的变化。 结果:荷瘤小鼠脾脏MDSC细胞的比例一直高于正常组;Treg细胞在荷瘤2 w时显著升高;总CD3+T细胞和CD4+T细胞在荷瘤1 w时显著升高,2 w时显著下降;CD8+T细胞在荷瘤2 w时明显下降;NK细胞在荷瘤3 w时明显下降;NKT细胞无显著变化。脾脏切除后外周血和肿瘤组织MDSC的比例下降,CD8+T细胞的比例升高;肿瘤重量和荷瘤小鼠生存期无显著变化,腹水量在荷瘤2 w时显著减少,腹水发生率明显降低。 结论:小鼠肝脏种植H22细胞株后,脾脏中正性免疫细胞的比例下降,负性免疫细胞的比例升高,脾脏的负性免疫状态逐渐占主导地位,从而促进了肝癌的发展。     

基于质谱流式细胞技术揭示TP53突变型乙型肝炎病毒相关性肝细胞癌的免疫微环境特征

目的 探讨TP53突变型乙型肝炎病毒（hepatitis B virus，HBV）相关性肝细胞癌（hepatocellular carcinoma，HCC）的肿瘤免疫微环境特征。方法 收集2018—2019年广西医科大学附属肿瘤医院肝胆外科手术切除的38例HCC患者活体组织标本及其配对癌旁组织标本，提取组织DNA，并进行基因突变分析。采用质谱流式细胞术（CyTOF）比较TP53突变组和TP53未突变组中癌组织与癌旁组织以及两组癌组织之间的免疫微环境特点。结果 采用CyTOF鉴定TP53突变组和TP53未突变组所有免疫细胞，结果鉴定为22个细胞亚群，包括CD4⁺T细胞亚群、CD8⁺T细胞亚群、B细胞亚群、树突细胞亚群、自然杀伤（natural killer cell，NK）细胞亚群、NKT细胞亚群、粒细胞亚群和2个未知细胞亚群。其中，TP53突变组癌组织中CD8⁺T细胞和CD4⁺T细胞的表达比例均较未突变组癌组织高（2.26% vs 0.47%，P=0.028；7.53% vs 3.55%，P=0.046）。结论 TP53突变型HBV相关性HCC的肿瘤免疫微环境具有免疫异质性。     

Dose and timing of total-body irradiation mediate tumor progression and immunomodulation

The major goal of this study was to examine the effects of total-body irradiation (TBI) on lung carcinoma progression and determine if changes in tumor growth could be correlated with radiation-induced alterations of immune system parameters. Lewis lung tumor cells were injected subcutaneously into syngeneic C57BL/6 mice that had been irradiated with a single 3.0 Gy dose of gamma-rays (60Co) at four time points either before or after tumor cell implantation. Subsequently, a second group of mice was irradiated 2 h prior to tumor injection with sequential doses of gamma-rays (0.46-2.66 Gy range). Assays were performed on blood and spleen from mice euthanized 16 days postimplantation. Tumor growth was consistently slower regardless of the timing of radiation exposure. However, dose of radiation influenced tumor growth delay. The preirradiated tumor-bearing mice had high CD4/CD8 T lymphocyte ratios along with increasing percentages of NKT cells in the blood supply with dose. Tumor-induced immunomodulation was also present, as evidenced by splenomegaly, low proliferative response to mitogens, and decreased spontaneous blastogenesis of leukocytes within the blood compared with normal values (P < or = 0.01). Anemia and thrombocytopenia were not observed with either tumor presence or irradiation. The present study demonstrates that a modest dose of TBI prior to tumor cell implantation resulted in a beneficial antitumor effect. A selective radiation-induced depletion of CD8+ T lymphocytes and changes in NKT cell percentages, correlated with findings from cytotoxicity assays, were indicative of a protumoricidal immune environment.     

Immune response to firefly luciferase as a naked DNA

Firefly luciferase (Fluc) has been widely used as a reporter gene. The aim of this study was to investigate immune response to luciferase protein after an intradermal injection of pcDNA3.1-Fluc in immunocompetent BALB/c mice. We observed bioluminescence at injection sites from one to seven days post-injection when pcDNA3.1-Fluc was intradermally injected into ear-pinnae. To observe induced immune response, the percentages of CD8+IFNgamma+ cells in the draining lymphoid cells of immunocompetent BALB/c mice immunized by pcDNA3.1-Fluc were measured. And the tumor growths of CT26/Fluc in pcDNA3.1-Fluc group were monitored by observing bioluminescent signals and measuring tumor mass, and these were compared with those of the pcDNA3.1 group in immunocompetent BALB/c mice and immunodeficient Nu/Nu mice. In the immunocompetent BALB/c mice, percentages of CD8+IFNgamma+ cells in the pcDNA3.1-Fluc group were higher than those in the pcDNA3.1 group. Ten days after tumor inoculation, tumor growth inhibition was found in the pcDNA3.1-Fluc group, but not in the pcDNA3.1 group in the immunocompetent BALB/c mice. No significant difference in tumor growth inhibition was observed when CT26/Fluc was injected into immunodeficient Nu/Nu mice. In terms of cytokine profiles of draining lymphoid cells of immunized mice, IFNgamma protein levels in the pcDNA3.1-Fluc group were higher than in pcDNA3.1 group animals among the immunocompetent BALB/c mice. In conclusion, Fluc induced a Th1 immune response to Fluc protein delivered by injecting pcDNA3.1-Fluc into immunocompetent BALB/c mice. We suggest that immune response to the Fluc gene is cautionary in preclinical or clinical trials involving the Fluc gene, and that the immunologic potential of firefly luciferase as a naked DNA may be useful in cancer immunotherapy.     

Therapeutic tumor immunity induced by polyimmunization with melanoma antigens gp100 and TRP-2

To improve the immunogenicity of melanoma self-antigens, we used a novel strategy of nonviral genetic vaccination coupled with muscle electroporation. Electroporation-enhanced immunization with plasmids encoding either human gp100 or mouse TRP-2 antigens induced only partial rejection of B16 melanoma challenge. However, immunization with a combination of these two antigens caused tumor rejection in 100% of the immunized mice. Splenocytes from combination-immunized animals killed syngeneic targets loaded with peptides derived from both gp100 and TRP-2. Immune cell depletion experiments identified CD8+ T lymphocytes as the primary effectors of antitumor immunity. Most importantly, polyimmunization led to the generation of a therapeutic immune response that significantly improved the mean survival time of mice bearing established lung metastases. These results validated the usefulness of electroporation-enhanced, nonviral genetic immunization for the active immunotherapy of cancer and indicated that using a combination of different tumor antigens may be a decisive strategy for a successful therapeutic vaccination.     

Increased Frequency of Foxp3+ Regulatory T Cells in Mice with Hepatocellular Carcinoma

The CD4+CD25+ regulatory T cell (Treg) is a special kind of T cell subset. Studies have showed that Tregcells are involved in a number of physiological processes and pathologic conditions such as autoimmune diseases,transplantation tolerance and cancer. Tregs with unique capacity for immune inhibition can impair anti-tumourimmunity and help tumor cells to escape from immune surveillance. The aim of our study was to investigatewhether Tregs are involved in hepatocellular carcinoma (HCC). A BABL/C mouse with HCC in situ model wasestablished to evaluate the Treg existence in carcinoma tissues and the changes of Tregs in spleen using flowcytometry and immunohistochemistry methods. Granzyme B expression in carcinoma tissues was analyzedby immunohistochemistry to investigate the tumor local immune status.The proportion of CD4+CD25+/CD4+spleen lymphocytes of tumor bearing mice (18.8%±1.26%) was found to be significantly higher than that innormal mice (9.99%±1.90%) (P<0.01 ). Immunohistochemistry of spleen tissue also confirmed that there wasan increase in Treg in tumor-bearing mice, while in carcinomas it showed Treg cells to be present in tumorinfiltrating lymphocyte areas while Granzyme B was rarely observed. Anti-tumour immunity was suppressed,and this might be associated with the increase of Tregs. Our observations suggest that the CD4+CD25+Treg/CD4+ proportion in spleen lymphocytes can be a sensitive index to evaluate the change of Tregs in hepatocellularcarcinoma mice and the Treg may be a promising therapeutic target for cancer.     

Peripheral blood mononuclear cells of patients with breast cancer can be reprogrammed to enhance anti-HER-2/neu reactivity and overcome myeloid-derived suppressor cells

Two major barriers in the immunotherapy of breast cancer include tumor-induced immune suppression and the establishment of long-lasting immune responses against the tumor. Recently, we demonstrated in an animal model of breast carcinoma that expanding and reprogramming tumor-sensitized lymphocytes, ex vivo, yielded T memory (Tm) cells as well as activated CD25+ NKT cells and NK cells. The presence of activated CD25+ NKT and NK cells rendered reprogrammed T cells resistant to MDSC-mediated suppression, and adoptive cellular therapy (ACT) of reprogrammed lymphocytes protected the host from tumor development and relapse. Here, we performed a pilot study to determine the clinical applicability of our protocol using peripheral blood mononuclear cells (PBMCs) of breast cancer patients, ex vivo. We show that bryostatin 1 and ionomycin combined with IL-2, IL-7, and IL-15 can expand and reprogram tumor-sensitized PBMCs. Reprogrammed lymphocytes contained activated CD25+ NKT and NK cells as well as Tm cells and displayed enhanced reactivity against HER-2/neu in the presence of MDSCs. The presence of activated NKT cells was highly correlated with the rescue of anti-HER-2/neu immune responses from MDSC suppression. Ex vivo blockade experiments suggest that the NKG2D pathway may play an important role in overcoming MDSC suppression. Our results show the feasibility of reprogramming tumor-sensitized immune cells, ex vivo, and provide rationale for ACT of breast cancer patients.     

Fourteenth Annual Pezcoller Symposium: the novel dichotomy of immune interactions with tumors

The main focus of the Symposium was the fact that cell types of the innate and adaptive immune systems can have tumor-favoring as well as tumor antagonistic effects, both in a preventive and therapeutic mode. It was shown that macrophages (Mphi) and dendritic cells within a tumor exert tumor-favoring effects through the action of certain cytokines. Inflammatory reactions could favor the onset and growth of tumors. Dual immune functions were shown with CD4+ T cells and certain matrix metalloproteinase (MMP) activities favoring tumor progression and CD8+ T cells and certain heat shock proteins having antitumor action. Lack of antitumor action despite positive immune stimulation was also shown to depend on the existence of barriers to tumor infiltration by lymphocytes; remodeling of vasculature, e.g., by IFNgamma-induced cytokines like MIG and IPIO, reversed this type of impediment. Certain CXC cytokines increased tumor progression, whereas others, particularly those induced by IFNgamma, had the opposite effect; stromal-derived factor-1 and its receptor CXCR4 affected tumor propensity to metastasize in certain organs. Stromal-derived factor-1 induced MMP9, which in turn regulated the bioavailability of vascular endothelial growth factor and the cascade of its tumor-favoring effects, whereas granulocyte colony-stimulating factor decreased MMP9 and the consequences of its action. The effects of certain proinflammatory cytokines and vascular endothelial growth factor functions in angiogenesis and lymphoangiogenesis were also discussed. The favoring effects of fever-like thermal stress on the function of molecules instrumental in lymphoid cell adhesion to vessels and infiltration into sites of immune actions were described. The mechanisms involved in the development of immune memory and those conditioning Type I and CTL responses were also discussed. A number of presentations were concerned with laboratory studies aimed at developing clinical regimens with potential activity in the prevention or treatment of cancer. Prevention of Her2/neu breast cancer in transgenic mice was achieved by suitable regimens with IL12 combined with vaccines, including DNA-based vaccines administered in conjunction with electroporation. Vaccination with shared tumor antigen MUCI or cyclin B was discussed, and its clinical translation was described. The prevention of TRAMP prostate tumor in transgenic mice by anti-CTLA4 antibody plus vaccine was described, as was the translation of these regimens to the clinics. Clinical successes in melanoma patients using antimelanoma antigen antibodies in a therapeutic mode and precautions to be exerted in evaluating in vivo immune responses based on in vitro assays were emphasized. The symposium was concluded with an overall discussion focused on basic questions related to the capability of immunity to exert tumor-favoring or antitumor effects depending on conditions determined by both tumor and host functions.