Depletion of regulatory T cells by anti-ICOS antibody enhances anti-tumor immunity of tumor cell vaccine in prostate cancer

ICOS⁺Treg cells exert important immunosuppressive effects in tumor immunity. We adopt a combination approach of ICOS⁺Treg cells depletion with tumor cell vaccine to evaluate anti-tumor immunity in mouse prostate cancer model. Streptavidin (SA)-mGM-CSF surface-modified RM-1 cells were prepared as the vaccine and the mouse subcutaneous prostate tumor model was used to evaluate the immunity. Tumor growth, flow cytometry, immunohistochemistry, immunofluorescence and enzyme linked immunosorbent assay (ELISA) were performed to evaluate the therapeutic effects. Our results demonstrated that SA-mGM-CSF vaccine was prepared successfully and tumor growth was inhibited. The tumor size in the combination group was much smaller than that in the vaccine with IgG mAb group. The portions of dendritic cells, CD8⁺ and CD4⁺T cells in the mice blood and tumor tissues were increased after treatment with vaccine. There were more immune-suppressing Tregs infiltrated into tumor after treatment with tumor cell vaccine, and ICOS blocking could deplete the infiltrated Tregs, and T lymphocytes increased more dramatically in the combination therapy group. The concentrations of interferon-γ were increased in all vaccine group, the concentrations of Interleukin-10 and Interleukin-4 were much lower in the combination group. Our study demonstrated that ICOS blocking could deplete the tumor-infiltrated ICOS⁺Treg cells. Combining GM-CSF surface-modified RM-1 cell vaccine with Anti-ICOS antibody could induce better antitumor immunity than a vaccine alone.     

Intratumoral injection of attenuated Salmonella vaccine can induce tumor microenvironmental shift from immune suppressive to immunogenic

Attenuated Salmonella vaccines show therapeutic anti-cancer effects, but the underlying mechanism has not been well investigated. In the current study, intratumoral (i.t.) injection of recombinant attenuated Salmonella enterica serovar Typhimurium vaccine (RASV) significantly inhibited Her-2/neu-expressing tumor growth. Although depletion of CD8⁺ cells in RASV-treated mice significantly restored tumor growth, the induction of Her-2/neu-specific cytotoxic T lymphocytes (CTLs) was not well correlated with the generation of the anti-tumor effect. Therefore, we hypothesized that RASV might induce a tumor microenvironmental shift, from immune suppressive to immunogenic, to reduce the suppressive force and finally elicit a successful anti-tumor response. We found that i.t. injection of RASV significantly increased the level of CD11b⁺Gr-1⁺ myeloid cells identified as myeloid-derived suppressor cell (MDSC), but a significant portion of these cells were TNF-α-secreting Ly6-G^high subsets, which can function as antitumor effector cells. We further investigated whether RASV can modulate immunosuppressive Treg cells, and CD4⁺CD25⁺ Foxp3⁺ Tregs was significantly reduced in RASV-treated mice. Thus, i.t. injection of RASV may offer a novel anti-cancer approach by eliciting transformation of immunosuppressive MDSCs into TNF-α-secreting neutrophils and reducing the generation of Treg cells, especially in the presence of tumor-specific CTLs. Collectively, these data will provide us an insight for the development of new anti-tumor approaches to overcome the immunosuppressive environment generated by tumors.     

Active hexose correlated compound potentiates the antitumor effects of low-dose 5-fluorouracil through modulation of immune function in hepatoma 22 tumor-bearing mice

BACKGROUND/OBJECTIVES

A variety of immunomodulators can improve the efficacy of low-dose chemotherapeutics. Active hexose correlated compound (AHCC), a mushroom mycelia extract, has been shown to be a strong immunomodulator. Whether AHCC could enhance the antitumor effect of low-dose 5-fluorouracil (5-FU) via regulation of host immunity is unknown.

MATERIALS/METHODS

In the current study Hepatoma 22 (H22) tumor-bearing mice were treated with PBS, 5-FU (10 mg·kg^-1·d^-1, i.p), or AHCC (360 mg·kg^-1·d^-1, i.g) plus 5-FU, respectively, for 5 d. CD3⁺, CD4⁺, CD8⁺, and NK in peripheral blood were detected by flow cytometry. ALT, AST, BUN, and Cr levels were measured by biochemical assay. IL-2 and TNFα in serum were measured using the RIA kit and apoptosis of tumor was detected by TUNEL staining. Bax, Bcl-2, and TS protein levels were measured by immunohistochemical staining and mRNA level was evaluated by RT-PCR.

RESULTS

Diet consumption and body weight showed that AHCC had no apparent toxicity. AHCC could reverse liver injury and myelosuppression induced by 5-FU (P < 0.05). Compared to mice treated with 5-FU, mice treated with AHCC plus 5-FU had higher thymus index, percentages of CD3⁺, CD4⁺, and NK cells (P < 0.01), and ratio of CD4⁺/CD8⁺ (P < 0.01) in peripheral blood. Radioimmunoassay showed that mice treated with AHCC plus 5-FU had the highest serum levels of IL-2 and TNFα compared with the vehicle group and 5-FU group. More importantly, the combination of AHCC and 5-FU produced a more potent antitumor effect (P < 0.05) and caused more severe apoptosis in tumor tissue (P < 0.05) compared with the 5-FU group. In addition, the combination of AHCC and 5-FU further up-regulated the expression of Bcl-2 associated X protein (Bax) (P < 0.01), while it down-regulated the expression of B cell lymphoma 2 (Bcl-2) (P < 0.01).

CONCLUSIONS

These results support the claim that AHCC might be beneficial for cancer patients receiving chemotherapy.     

Frequencies of CD4+ T Regulatory Cells and their CD25high and FoxP3high Subsets Augment in Peripheral Blood of Patients with Acute and Chronic Brucellosis

Objectives

Brucellosis remains one of the most common zoonotic diseases worldwide. In humans, brucellosis can be a serious, debilitating, and sometimes chronic disease. Different mechanisms can be postulated as to the basis for the induction of the chronic status of infectious diseases that T regulatory cells are one of the most important related mechanisms. The current study was designed to determine whether percentage of CD4+Treg cells and their CD25^high and FoxP3^high subpopulations in peripheral blood are changed in human brucellosis samples in comparison to a control group.

Methods

In total, 68 brucellosis patients (acute form: n = 43, chronic form: n = 25) and 36 healthy volunteers entered our study. After isolating of peripheral blood mononuclear cells, heparinized venous blood samples were obtained from both patients and healthy donors, CD4, CD25, and FoxP3 molecules were evaluated by two- and three-color flow cytometric methods.

Results

The results revealed a new finding in relation to Treg cells and human brucellosis. The numbers of CD4⁺Treg cells and their CD25^high and FoxP3^high subsets increase significantly in the peripheral blood of acute and chronic forms of brucellosis samples compared with healthy groups, with this increase being greater in the chronic group.

Conclusion

There seems to be a correlation between increase of CD4+Treg cells and their subsets and the disease progress from healthy state to acute and chronic brucellosis.     

Nicaraven mitigates radiation-induced lung injury by downregulating the NF-κB and TGF-β/Smad pathways to suppress the inflammatory response

Radiation-induced lung injury (RILI) is commonly observed in patients receiving radiotherapy, and clinical prevention and treatment remain difficult. We investigated the effect and mechanism of nicaraven for mitigating RILI. C57BL/6 N mice (12-week-old) were treated daily with 6 Gy X-ray thoracic radiation for 5 days in sequences (cumulative dose of 30 Gy), and nicaraven (50 mg/kg) or placebo was injected intraperitoneally in 10 min after each radiation exposure. Mice were sacrificed and lung tissues were collected for experimental assessments at the next day (acute phase) or 100 days (chronic phase) after the last radiation exposure. Of the acute phase, immunohistochemical analysis of lung tissues showed that radiation significantly induced DNA damage of the lung cells, increased the number of Sca-1⁺ stem cells, and induced the recruitment of CD11c⁺, F4/80⁺ and CD206⁺ inflammatory cells. However, all these changes in the irradiated lungs were effectively mitigated by nicaraven administration. Western blot analysis showed that nicaraven administration effectively attenuated the radiation-induced upregulation of NF-κB, TGF-β, and pSmad2 in lungs. Of the chronic phase, nicaraven administration effectively attenuated the radiation-induced enhancement of α-SMA expression and collagen deposition in lungs. In conclusion we find that nicaraven can effectively mitigate RILI by downregulating NF-κB and TGF-β/pSmad2 pathways to suppress the inflammatory response in the irradiated lungs.     

Maturation of human dendritic cells with Saccharomyces cerevisiae (yeast) reduces the number and function of regulatory T cells and enhances the ratio of antigen-specific effectors to regulatory T cells

We compared the effects of yeast-treated human dendritic cells (DCs) with CD40L-matured human DCs for the induction of effector cells and the number and functionality of CD4⁺CD25⁺CD127⁻FoxP3⁺ regulatory T cells (Tregs). DCs were treated with yeast or CD40L and cocultured with isolated autologous CD4⁺ T cells. CD4⁺CD25⁺CD127⁻ T cells isolated from the coculture of CD4⁺ T cells plus yeast-treated DCs (yeast coculture) had a lower expression of FoxP3 and decreased suppressive function compared to CD4⁺CD25⁺CD127⁻ T cells isolated from the coculture of CD4⁺ T cells plus CD40L-treated DCs (CD40L coculture). Also, compared to the CD40L coculture, the yeast coculture showed increases in the ratio of CD4⁺CD25⁺ activated T cells to Tregs and in the production of Th1-related cytokines (IL-2, TNF-α, IFN-γ) and IL-6. In addition, yeast-treated DCs used as antigen-presenting cells (APCs) incubated with the tumor antigen CEA enhanced the proliferation of CEA-specific CD4⁺ T cells compared to the use of CD40L-matured DCs used as APCs. This is the first study to report on the role of yeast-treated/matured human DCs in reducing Treg frequency and functionality and in enhancing effector to Treg ratios. These results provide an additional rationale for the use of yeast as a vector in cancer vaccines.     

A Mage3/Heat Shock Protein70 DNA vaccine induces both innate and adaptive immune responses for the antitumor activity

Heat shock proteins (HSPs) are highly effective and versatile molecules in promoting antitumor immune responses. We tested whether a HSP-based DNA vaccine can induce effective immune response against Mage3, a cancer testis (CT) antigen frequently expressed in many human tumors, thereby controlling the Mage3-expressing tumor. The vaccine was constructed by linking human inducible HSP70 to the C-terminus of a modified Mage3 gene (sMage3) that was attached at its N-terminus with the signal leader sequence of the human RANTES for releasing the expressed fusion protein from the transduced cells. Intramuscular injection of sMage3Hsp DNA induced CD4⁺/CD8⁺ T cell and antibody responses. Vaccination with sMage3Hsp DNA was more effective in inhibiting Mage3-expressing TC-1 tumors. When we dissected the antitumor activity of CD4⁺ and CD8⁺ T cells by immunizing CD4⁺ and CD8⁺ knockout mice with sMage3Hsp DNA, we found that both CD8⁺ T and CD4⁺ T cells played a role in control of inoculated tumor, but did not constitute the whole of immune protection in the prophylactic immunization. Instead, depletion of natural killer (NK) cells led to a major loss of antitumor activity in the immunized mice. These results indicate that the HSP-based Mage3 DNA vaccine can more effectively inhibit tumor growth by inducing both the innate immune responses and Mage3-specific adaptive immune responses via the Hsp-associated adjuvant function.     

Characteristics of human CD34+ cells exposed to ionizing radiation under cytokine-free conditions

To clarify the mechanisms underlying radiation-induced hematopoietic stem cell death, we investigated the effects of excessive ionizing radiation on the clonogenic potential of CD34⁺ cells obtained from human umbilical cord blood under cytokine-free conditions. The CD34⁺ cells were X-ray–irradiated (up to 2 Gy) and were cultured for 0–48 h under cytokine-free conditions. At various time-points, the CD34⁺ cells were investigated for survival, clonogenic potential and the generation of mitochondrial superoxide. At 12 h after X-ray irradiation, the number of viable cells had decreased to ∼70–80% compared with the 0-h non-irradiated control, whereas the clonogenic potential in the X-ray–irradiated cells had decreased to ∼50%–60% compared with the 0-h non-irradiated control. Furthermore, significant generation of mitochondrial superoxide was observed at 6 h, and reached a maximum value between 12 and 24 h after X-ray irradiation. However, no significant differences were observed between non-irradiated and X-ray–irradiated cells in terms of the generation of reactive oxygen species or in the intracellular mitochondrial contents. In addition, a cDNA microarray analysis showed that the majority of the altered genes in the CD34⁺ cells at 6 h after X-ray irradiation were apoptosis-related genes. These results suggest the possibility that the elimination of the clonogenic potentials of CD34⁺ cells involves the generation of mitochondrial superoxide induced by ionizing radiation.     

β-carotene regulates cancer stemness in colon cancer in vivo and in vitro

BACKGROUND/OBJECTIVESColorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness.MATERIALS/METHODSCD133⁺CD44⁺ HCT116 and CD133⁺CD44⁺ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133⁺CD44⁺ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors.RESULTSBC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133⁺CD44⁺ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well.CONCLUSIONSThese results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.     

Decrease in circulating CD25hiFoxp3+ regulatory T cells following vaccination with the candidate malaria vaccine RTS,S

Regulatory T (Treg) cells have been shown in some cases to limit vaccine-specific immune responses and impact efficacy. Very little is known about the regulatory responses to the leading malaria vaccine candidate, RTS,S. The goal of this study was to begin to characterize the regulatory responses to the RTS,S vaccine. Using multi-parameter flow cytometry, we examined responses in 13 malaria naïve adult volunteers who received 2 doses of RTS,S given eight weeks apart. Five of these volunteers had previously received 3 doses of a candidate DNA-CSP vaccine, with the final dose given approximately one year prior to the first dose of the RTS,S vaccine.We found that the frequency of CD25^hiFoxp3⁺ Treg cells decreased following administration of RTS,S (p = 0.0195), with no differences based on vaccine regimen. There was a concomitant decrease in CTLA-4 expression on CD25^hiFoxp3⁺ Treg cells (p = 0.0093) and PD-1 levels on CD8⁺ T cells (p = 0.0002). Additionally, the frequency of anergic CTLA-4⁺CCR7⁺ T cells decreased following vaccination. An inverse correlation was observed between the frequency of Plasmodium falciparum circumsporozoite protein (PfCSP)-specific IFN-γ and PfCSP-specific IL-10, as well as an inverse correlation between IL-10 induced by Hepatitis B surface antigen, the carrier of RTS,S, and PfCSP-specific IFN-γ, suggesting that immunity against the vaccine backbone could impact vaccine immunogenicity. These results have implications for future malaria vaccine design.     

Adjuvant-active aqueous extracts from Artemisia rupestris L. improve immune responses through TLR4 signaling pathway

Activating innate immunity by an adjuvant is required in vaccine development. The study aims to investigate adjuvant effects of aqueous extracts of Artemisia rupestris L. (AEAR) in vivo and in vitro. ICR mice were subcutaneously administered with antigen and AEAR at various doses to evaluate their immune responses of antibodies, dendritic cells (DCs), regulatory T cells (Treg), splenic lymphocyte, and cytokine. The evaluation results showed that AEAR could largely increase titers of antigen-specific antibodies (IgG, IgG₁, and IgG_2a) and T cell proliferation. AEAR also increased expression of IFN-γ in CD8⁺T cells as well as IL-4 and INF-γ expression in CD4⁺T cells. Expression levels of MHC-II, CD40, CD80, and CD86 on DCs were significantly elevated, whereas the Treg frequency was significantly decreased. AEAR (200 μg) showed remarkable adjuvant activity. Furthermore, AEAR enhanced MHC-II, CD40, CD80, and CD86 expression as well as the yields of TNF-α and IL-12 on DCs through toll-like receptor4 (TLR4) in vitro. Those results indicated that AEAR could serve as an efficacious immune stimulator for vaccines because it significantly enhanced specific immune responses by promoting DCs maturation and reduced Treg through TLR4 signaling pathway.     

Delivery of antigenic candidates by a DNA/MVA heterologous approach elicits effector CD8T cell mediated immunity against Trypanosoma cruzi

In this study, we have characterized the immune mechanisms elicited by antigenic candidates, TcG2 and TcG4, delivered by a DNA-prime/MVA-boost approach, and evaluated the host responses to Trypanosoma cruzi infection in C57BL/6 mice. Immunization of mice with antigenic candidates elicited antigen-specific, high-avidity, trypanolytic antibody response (IgG2b > IgG1) and CD8⁺T cells that exhibited type-1 cytolytic effector (CD8⁺CD107a⁺IFN-γ⁺Perforin⁺) phenotype. The extent of TcG2-dependent type 1 B and T cell immunity was higher than that noted in TcG4-immunized mice, and expanded accordingly in response to challenge infection with T. cruzi. The progression of chronic phase in immunized mice was associated with persistence of IgGs, 55–90% reduction in the frequency of proinflammatory (IFN-γ⁺ or TNF-α⁺) CD8⁺T cells, and an increase or emergence of immunoregulatory (IL-10⁺) CD4/CD8 T cells. The tissue parasitism, infiltration of inflammatory infiltrate, parasite persistence, and fibrosis were decreased by 82–92% in heart and skeletal muscle of immunized/chronically infected mice. Control mice exhibited a significantly low antibody response, consistent activation of effector CD8⁺T cells dominated by pro-inflammatory phenotype and mixed cytokine profile (IFN-γ + TNF-α > IL-4 + IL-10), parasite persistence and pathologic damage in chagasic hearts. We conclude that delivery of TcG2 or TcG4 by DNA-rMVA approach elicits effective antibody and CD8⁺T cell mediated immunity against T. cruzi and Chagas disease. The emergence of type 2 cytokine and T cell response in chronic phase was indicative of prevention of clinical disease.     

Heterologous human/rat HER2-specific exosome-targeted T cell vaccine stimulates potent humoral and CTL responses leading to enhanced circumvention of HER2 tolerance in double transgenic HLA-A2/HER2 mice

DNA vaccines composed of heterologous human HER2 and rat neu sequences induce stronger antibody response and protective antitumor immunity than either HER2 or neu DNA vaccines in transgenic mice. We previously developed HER2-specific exosome-targeted T-cell vaccine HER2-T_EXO capable of stimulating HER2-specific CD8⁺ T-cell responses, but only leading to partial protective immunity in double-transgenic HLA-A2/HER2 mice with self-immune tolerance to HER2. Here, we constructed an adenoviral vector AdV_HuRt expressing HuRt fusion protein composed of NH₂-HER2_1-407 (Hu) and COOH-neu_408-690 (Rt) fragments, and developed a heterologous human/rat HER2-specific exosome-targeted T-cell vaccine HuRt-T_EXO using polyclonal CD4⁺ T-cells uptaking exosomes released by AdV_HuRt-transfected dendritic cells. We found that the HuRt-T_EXO vaccine stimulates enhanced CD4⁺ T-cell responses leading to increased induction of HER2-specific antibody (∼70 µg/ml) compared to that (∼40 µg/ml) triggered by the homologous HER2-T_EXO vaccine. By using PE-H-2K^d/HER2_23-71 tetramer, we determined that HuRt-T_EXO stimulates stronger HER2-specific CD8⁺ T-cell responses eradicating 90% of HER2-specific target cells, while HER2-T_EXO-induced CD8⁺ T-cell responses only eliminating 53% targets. Furthermore, HuRt-T_EXO, but not HER2-T_EXO vaccination, is capable of suppressing early stage-established HER2-expressing 4T1_HER2 breast cancer in its lung metastasis or subcutaneous form in BALB/c mice, and of completely protecting transgenic HLA-A2/HER2 mice from growth of HLA-A2/HER2-expressing BL6-10_A2/HER2 melanoma. HuRt-T_EXO-stimulated HER2-specific CD8⁺ T-cells not only are cytolytic to trastuzumab-resistant HLA-A2/HER2-expressing BT474/A2 breast tumor cells in vitro but also eradicates pre-established BT474/A2 tumors in athymic nude mice. Therefore, our novel heterologous human/rat HER2-specific T-cell vaccine HuRt-T_EXO, circumventing HER2 tolerance, may provide a new therapeutic alternative for patients with trastuzumab-resistant HER2⁺ breast tumor.     

Ovalbumin lipid core peptide vaccines and their CD4 and CD8 T cell responses

The lipid core peptide (LCP) system has successfully been used in development of peptide-based vaccines against cancer and infectious diseases (such as group A streptococcal infection). CD8⁺ T cells are important targets for vaccines, however developing a vaccine that activates long-lasting immunity has proven challenging. The ability of LCP vaccines to activate antigen-specific CD8⁺ and/or CD4⁺ T cell responses was tested using compounds that contained two or four copies of OVA_257–264 and/or OVA_323–339 peptides conjugated to LCP, which are recognised by OTI (CD8⁺ specific) and OTII (CD4⁺ specific) T cells, respectively. The LCP–ovalbumin vaccines developed in this study were synthesised in 30% yields and showed no significant haemolytic effect on red blood cells (below 4% haemolysis when tested with compounds at up to 100 μM concentrations). Promising in vivo data in mice suggested that this LCP–ovalbumin vaccine system could act as a novel and potent vehicle for the stimulation of robust antigen-specific CD8⁺ T cell responses.     

Energy-restricted diets result in higher numbers of CD4, CD8, immunoglobulins (A, M, and G), and CD45RA cells in spleen and CD4, immunoglobulin A, and CD45RA cells in colonic lamina propria of rats

Dietary energy restriction (ER) offers certain health benefits, particularly when ER is controlled through manipulation of dietary fats. Our hypothesis is that cellular immunity is modulated by dietary ER. Furthermore, we believe that the immune response may differ between spleen and colon because their lymphatic and vascular organization is different. The objective of the study was to test this hypothesis by determining the effects of dietary ER through manipulation of energy intake from high-fat (HF) diets on the expression and frequency of the CD4⁺ (T-helper/T-inducer) and CD8⁺ (T-cytotoxic/T-suppressor) cells, CD45RA (B-cell–specific marker), and immunoglobulins (Ig) A-, G-, and M-bearing cells in spleen and colon in rats by immunohistochemical method. Rats fed the HF diet had a significantly (P < .05) reduced number of immune cells as compared with those fed ER diets. Energy-restricted diet–fed rats showed higher (P < .05) numbers of CD4⁺, CD8⁺, IgA, IgM, IgG, and CD45RA cells in spleen and CD4⁺, IgA, and CD45RA cells in colonic lamina propria. The IgA-containing cells were markedly higher in the colon compared with the spleen. No change occurred in the number of IgM- and IgG-containing cells in colonic tissues between groups, except for the 20% ER group where IgM-labeled cells were higher (P < .05) compared with HF and 40% ER groups. These findings suggest that ER may modulate adaptive immune function and that CD4⁺ and IgA cells may serve as biological indicators for dietary energy-modulated immunoresponse in spleen and colon, respectively.     

Profound CD8+ T cell immunity elicited by sequential daily immunization with exogenous antigen plus the TLR3 agonist poly(I:C)

The development of vaccines that elicit robust CD8⁺ T cell immunity has long been a subject of intense investigation. Although whole exogenous protein has not historically been considered as useful for eliciting CD8⁺ T cell immunity, we report herein that whole, protein antigen is capable of eliciting profound levels of CD8⁺ T cell immunity if it is administered via repeated, daily subcutaneous immunization in combination with the TLR3 agonist poly(I:C). Mice immunized for four consecutive days with 100 μg of either whole exogenous OVA or whole HPV16 E7 protein combined with 10 μg of poly(I:C) mounted remarkable antigen-specific CD8⁺ T cell responses as measured by tetramer staining and ELISPOT analysis of splenocytes and peripheral blood, with up to 30% of peripheral CD8⁺ T cells being antigen specific within 7-8 days of vaccination. CD8⁺ T cell immunity elicited using this vaccination approach was critically dependent upon cross presentation, as either whole protein or long synthetic peptides were highly effective immunogens whereas minimal peptide epitopes were not. Vaccine-induced CD8⁺ T cells were also able to regress large, established tumors in vivo. Together these data suggest that ‘cluster’ vaccination with exogenous antigen combined with TLR3 agonist may constitute a profoundly important advancement in therapeutic vaccine design.     

Efficacy of intraoperative radiotherapy targeted to the abdominal lymph node area in patients with esophageal carcinoma

We investigated whether intraoperative radiotherapy (IORT) during curative surgery for esophageal carcinoma is useful or not. The cases of 117 patients diagnosed with thoracoabdominal esophageal carcinoma who underwent curative surgery between 1986 and 2007 were reviewed: 72 patients received IORT (IORT group) and 45 did not (non-IORT group). Upper abdominal lymphadenectomy was performed in 115 patients (98.5%). Seventy patients (59.8%) received chemotherapy and 80 patients (68.4%) received external radiotherapy. IORT encompassed the upper abdominal lymph node area. A single-fraction dose of 20–30 Gy was delivered using high-energy electrons. Median follow-up duration for patients was 7.4 years. The 5-year overall survival rate did not significantly differ between the IORT and non-IORT groups. However, the 5-year abdominal control rate was significantly higher in the IORT group (89.2%) than in the non-IORT group (72.9%; P = 0.022). We next focused on a patient subgroup with a primary lesion in the lower thoracic or abdominal esophagus or measuring >6 cm in length since this subgroup is probably at high risk of upper abdominal lymph node metastasis. Of the 117 patients, 75 belonged to this subgroup, and among them 45 received IORT. Both univariate and multivariate analysis revealed the survival rate was significantly higher in patients who received IORT than in those who did not (P = 0.033 univariate; 0.026 multivariate). There were no obvious perioperative complications solely attributed to IORT. IORT for esophageal carcinoma will likely be effective for patients with a primary lesion in the lower thoracic or abdominal esophagus, or with a long lesion.     

Effect and Tolerability of a Nutritional Supplement Based on a Synergistic Combination of β-Glucans and Selenium- and Zinc-Enriched Saccharomyces cerevisiae (ABB C1®) in Volunteers Receiving the Influenza or the COVID-19 Vaccine: A Randomized,Double-Blind,Placebo-Controlled Study

A single-center, randomized, double-blind, placebo-controlled study was conducted in 72 volunteers who received a synergistic combination of yeast-based ingredients with a unique β-1,3/1,6-glucan complex and a consortium of heat-treated probiotic Saccharomyces cerevisiae rich in selenium and zinc (ABB C1^®) or placebo on the next day after getting vaccinated against influenza (Chiromas^®) (n = 34) or the COVID-19 (Comirnaty^®) (n = 38). The duration of treatment was 30 and 35 days for the influenza and COVID-19 vaccine groups, respectively. Mean levels of CD4+T cells increased from 910.7 at baseline to 1000.2 cells/µL after the second dose of the COVID-19 vaccine in the ABB C1^® group, whereas there was a decrease from 1055.1 to 929.8 cells/µL in the placebo group. Changes of CD3+T and CD8+T lymphocytes showed a similar trend. In the COVID-19 cohort, the increases in both IgG and IgM were higher in the ABB C1^® supplement than in the placebo group. Serum levels of selenium and zinc showed a higher increase in subjects treated with the active product than in those receiving placebo. No serious adverse events related to ABB C1^® or tolerance issues were reported. The study findings validate the capacity of the ABB C1^® product to stimulate trained immunity.     

Molecular adjuvant IL-33 enhances the potency of a DNA vaccine in a lethal challenge model

Identifying new molecular adjuvants that elicit effective vaccine-induced CD8⁺ T cell immunity may be critical for the elimination of many challenging diseases including Tuberculosis, HIV and cancer. Here, we report that co-administration of molecular adjuvant IL-33 during vaccination enhanced the magnitude and function of antigen (Ag)-specific CD8⁺ T cells against a model Ag, LCMV NP target protein. These enhanced responses were characterized by higher frequencies of Ag-specific, polyfunctional CD8⁺ T cells exhibiting cytotoxic characteristics. Importantly, these cells were capable of robust expansion upon Ag-specific restimulation in vivo and conferred remarkable protection against a high dose lethal LCMV challenge. In addition, we demonstrate the ability of IL-33 to amplifying the frequency of Ag-specific KLRG1⁺ effector CD8⁺ T cells. These data show that IL-33 is a promising immunoadjuvant at improving T cell immunity in a vaccine setting and suggest further development and understanding of this molecular adjuvant for strategies against many obstinate infectious diseases and cancer.