Characterization and application of two novel monoclonal antibodies against 2IgB7-H3: expression analysis of 2IgB7-H3 on dendritic cells and tumor cells

Removal of CD276+ cells from haploidentical memory T-cell grafts significantly lowers the risk of GVHD

Detrimental graft-versus-host disease (GVHD) still remains a major cause of death in hematopoietic stem cell transplantation (HSCT). The recently explored depletion of naive cells from mobilized grafts (CD45RA depletion) has shown considerable promise, yet is unable to eliminate the incidence of GVHD. Analysis of CD45RA-depleted haploidentical mixed lymphocytes culture (haplo-MLC) revealed insufficient suppression of alloresponses in the CD4⁺ compartment and identified CD276 as a marker for alloreactive memory Th1 T cells. Conclusively, depleting CD276⁺ cells from CD45RA-depleted haplo-MLC significantly attenuated alloreactivity to recipient cells while increasing antiviral reactivity and maintaining anti-third party reactivity in vitro. To evaluate these findings in vivo, bulk, CD45RA-depleted, or CD45RA/CD276-depleted CD4⁺ T cells from HLA-DR4^negative healthy humans were transplanted into NSG-Ab°DR4 mice, a sensitive human allo-GVHD model. Compellingly, CD45RA/CD276-depleted grafts from HLA-DR4^negative donors or in vivo depletion of CD276⁺ cells after transplant of HLA-DR4^negative memory CD4 T cells significantly delay the onset of GVHD symptoms and significantly alleviate its severity in NSG-Ab°DR4 mice. The clinical courses correlated with diminished Th1-cytokine secretion and downregulated CXCR6 expression of engrafted peripheral T cells. Collectively, mismatched HLA-mediated GVHD can be controlled by depleting recipient-specific CD276⁺ alloreacting T cells from the graft, highlighting its application in haplo-HSCT.

Targeting B7-H3 via chimeric antigen receptor T cells and bispecific killer cell engagers augments antitumor response of cytotoxic lymphocytes

BACKGROUND

B7-H3, an immune-checkpoint molecule and a transmembrane protein, is overexpressed in non-small cell lung cancer (NSCLC), making it an attractive therapeutic target. Here, we aimed to systematically evaluate the value of B7-H3 as a target in NSCLC via T cells expressing B7-H3-specific chimeric antigen receptors (CARs) and bispecific killer cell engager (BiKE)-redirected natural killer (NK) cells.

METHODS

We generated B7-H3 CAR and B7-H3/CD16 BiKE derived from an anti-B7-H3 antibody omburtamab that has been shown to preferentially bind tumor tissues and has been safely used in humans in early-phase clinical trials. Antitumor efficacy and induced-immune response of CAR and BiKE were evaluated in vitro and in vivo. The effects of B7-H3 on aerobic glycolysis in NSCLC cells were further investigated.

RESULTS

B7-H3 CAR-T cells effectively inhibited NSCLC tumorigenesis in vitro and in vivo. B7-H3 redirection promoted highly specific T-cell infiltration into tumors. Additionally, NK cell activity could be specially triggered by B7-H3/CD16 BiKE through direct CD16 signaling, resulting in significant increase in NK cell activation and target cell death. BiKE improved antitumor efficacy mediated by NK cells in vitro and in vivo, regardless of the cell surface target antigen density on tumor tissues. Furthermore, we found that anti-B7-H3 blockade might alter tumor glucose metabolism via the reactive oxygen species-mediated pathway.

CONCLUSIONS

Together, our results suggest that B7-H3 may serve as a target for NSCLC therapy and support the further development of two therapeutic agents in the preclinical and clinical studies.

A novel monoclonal antibody against human B7-1 protects against chronic graft-vs.-host disease in a murine lupus nephritis model

Lupus nephritis (LN) is the most common complication that causes mortality in patients with systemic lupus erythematosus. The B7-1/B7-2 and CD28/cytotoxic T-lymphocyte associated protein 4 co-stimulatory pathway serves a key role in autoimmune disease and organ transplantation. The aim of the present study was to generate and characterize a monoclonal antibody (mAb; clone 4E5) against human B7-1 and to investigate its potential use for the treatment of LN. The results demonstrated that the 4E5 mAb was successfully generated and able to recognize both human and mouse B7-1. After injection of this mAb into a mouse model with chronic graft-vs.-host disease (cGVHD)-induced lupus-like disease, the expression of CD21, CD23, CD80 and CD86 on B220⁺ B-cells in the spleen, and the concentrations of serum autoantibodies and urine protein, were decreased. Direct immunofluorescence analysis of the kidneys revealed that immunofluorescence of immune complex deposits was weaker in the 4E5-treated mice and electron microscopy analyses of renal tissues indicated that pathological injury of the kidneys of 4E5-treated mice was decreased compared with that in the model control mice. The results of the present study demonstrated that inhibition of the B7-1/CD28 co-stimulatory signaling pathway with the 4E5 mAb may represent a promising strategy to decelerate the progression of LN that is induced by cGVHD with potential for use in the treatment of other autoimmune diseases.

B7-H3-targeted Radioimmunotherapy of Human Cancer

BACKGROUND

Targeted Radioimmunotherapy (RIT) is an attractive approach to selectively localize therapeutic radionuclides to malignant cells within primary and metastatic tumors while sparing normal tissues from the effects of radiation. Many human malignancies express B7-H3 on the tumor cell surface, while expression on the majority of normal tissues is limited, presenting B7-H3 as a candidate target for RIT. This review provides an overview of the general principles of targeted RIT and discusses publications that have used radiolabeled B7-H3-targeted antibodies for RIT of cancer in preclinical or clinical studies.

METHODS

Databases including PubMed, Scopus, and Google Scholar were searched for publications through June 2018 using a combination of terms including "B7-H3", "radioimmunotherapy", "targeted", "radiotherapy", and "cancer". After screening search results for relevancy, ten publications were included for discussion.

RESULTS

B7-H3-targeted RIT studies to date range from antibody development and assessment of novel Radioimmunoconjugates (RICs) in animal models of human cancer to phase II/III trials in humans. The majority of clinical studies have used B7-H3-targeted RICs for intra- compartment RIT of central nervous system malignancies. The results of these studies have indicated high tolerability and favorable efficacy outcomes, supporting further assessment of B7-H3-targeted RIT in larger trials. Preclinical B7-H3-targeted RIT studies have also shown encouraging therapeutic outcomes in a variety of solid malignancies.

CONCLUSION

B7-H3-targeted RIT studies over the last 15 years have demonstrated feasibility for clinical development and support future assessment in a broader array of human malignancies. Future directions worthy of exploration include strategies that combine B7-H3- targeted RIT with chemotherapy or immunotherapy.

Helicobacter pylori elicits B7H3 expression on gastric epithelial cells: Implications in local T cell regulation and subset development during infection

Helicobacter pylori (H. pylori) is a gram negative bacterium that infects more than 50% of humanity and is associated with gastritis, peptic ulcer and gastric cancer. Although CD4⁺ T cells are recruited to the gastric mucosa, the host is unable to clear the bacteria. Previously, we demonstrated that H. pylori infection upregulates the expression of the T cell co-inhibitory molecule B7-H1 while simultaneously downregulating the expression of T cell co-stimulatory molecule B7-H2 on gastric epithelial cells (GEC), which together affect the Treg and Th17 cell balance and foster bacterial persistence. Because B7-H3, another member of the B7 family of co-inhibitory receptors, has been found to have important immunoregulatory roles and in cancer, in this study we examined the expression of B7-H3 molecules on GEC and how the expression is regulated by H. pylori during infection. Our study showed that both human and murine GEC constitutively express B7-H3 molecules, but their expression levels increased during H. pylori infection. We further demonstrated that H. pylori uses its type 4 secretion system (T4SS) components CagA and cell wall peptidoglycan (PG) fragment to upregulate B7-H3. Th17 cells and Treg cells which are increased during H. pylori infection also had an effect on B7-H3 induction. The underlying cell signaling pathway involves modulation of p38MAPK pathway. Since B7-H3 were shown to up-regulate Th2 responses, the phenotype of T cell subpopulations in mice infected with H. pylori PMSS1 or SS1 strains were characterized. A mixed Th1/Th2 response in H. pylori infected mice was observed. Consistent with previous findings, increased Treg cells and decreased Th17 cells in MLN of PMSS1 infected mice compared to SS1 infected mice was observed. Human biopsy samples collected from gastritis biopsies and gastric tumors showed a strong association between increased B7-H3 and Th2 responses in H. pylori strains associated with gastritis. T cell: GEC co-cultures and anti-B7-H3 blocking Ab confirmed that the induction of Th2 is mediated by B7-H3 and associated exclusively with an H. pylori gastritis strain not cancer or ulcer strains. In conclusion, these studies revealed a novel regulatory mechanism employed by H. pylori to influence the type of T cell response that develops within the infected gastric mucosa.

Helicobacter pylori elicits B7H3 expression on gastric epithelial cells: Implications in local T cell regulation and subset development during infection

Helicobacter pylori (H. pylori) is a gram negative bacterium that infects more than 50% of humanity and is associated with gastritis, peptic ulcer and gastric cancer. Although CD4+ T cells are recruited to the gastric mucosa, the host is unable to clear the bacteria. Previously, we demonstrated that H. pylori infection upregulates the expression of the T cell co-inhibitory molecule B7-H1 while simultaneously downregulating the expression of T cell co-stimulatory molecule B7-H2 on gastric epithelial cells (GEC), which together affect the Treg and Th17 cell balance and foster bacterial persistence. Because B7-H3, another member of the B7 family of co-inhibitory receptors, has been found to have important immunoregulatory roles and in cancer, in this study we examined the expression of B7-H3 molecules on GEC and how the expression is regulated by H. pylori during infection. Our study showed that both human and murine GEC constitutively express B7-H3 molecules, but their expression levels increased during H. pylori infection. We further demonstrated that H. pylori uses its type 4 secretion system (T4SS) components CagA and cell wall peptidoglycan (PG) fragment to upregulate B7-H3. Th17 cells and Treg cells which are increased during H. pylori infection also had an effect on B7-H3 induction. The underlying cell signaling pathway involves modulation of p38MAPK pathway. Since B7-H3 were shown to up-regulate Th2 responses, the phenotype of T cell subpopulations in mice infected with H. pylori PMSS1 or SS1 strains were characterized. A mixed Th1/Th2 response in H. pylori infected mice was observed. Consistent with previous findings, increased Treg cells and decreased Th17 cells in MLN of PMSS1 infected mice compared to SS1 infected mice was observed. Human biopsy samples collected from gastritis biopsies and gastric tumors showed a strong association between increased B7-H3 and Th2 responses in H. pylori strains associated with gastritis. T cell: GEC co-cultures and anti-B7-H3 blocking Ab confirmed that the induction of Th2 is mediated by B7-H3 and associated exclusively with an H. pylori gastritis strain not cancer or ulcer strains. In conclusion, these studies revealed a novel regulatory mechanism employed by H. pylori to influence the type of T cell response that develops within the infected gastric mucosa.

Therapy to target renal cell carcinoma using 131I-labeled B7-H3 monoclonal antibody

B7-H3 is a tumor-associated antigen that plays a critical role in potential tumor-targeted therapy. In this study, we aimed to assess the radiobiological effect of ¹³¹I-labeled B7-H3 monoclonal antibody (¹³¹I-4H7) in nude mice with human renal cell carcinoma (RCC) and evaluate the effect of ¹³¹I-4H7 on RCC treatment. The radiobiological activity and tumor uptake of ¹³¹I-4H7, and its effect on tumor growth were measured. ¹³¹I-4H7 was absorbed by the tumor and reached its maximal uptake rate (3.32% injected dose [ID]/g) at 24 h, at which point the drug concentration in the tumor was 7.36-, 2.06-, 1.80-, and 2.78-fold higher than that in muscle, kidneys, liver, and heart, respectively. Measurements and positron emission tomography–computed tomography imaging showed that tumor development was significantly inhibited by ¹³¹I-4H7. HE staining revealed that ¹³¹I-4H7 significantly injures tumor cells. Our results suggest that ¹³¹I-4H7 is markedly absorbed by the tumor and did suppress the development of RCC xenografted tumors in nude mice, which might provide a new candidate for antibody-mediated targeted radiotherapy in human RCC.

B7-H3 combats apoptosis induced by chemotherapy by delivering signals to pancreatic cancer cells

Objective

This study aimed to investigate the role of B7-H3 in chemotherapy resistance of pancreatic cancer cells and discover the potential signal transduction pathway and molecular targets involved.

Methods

Immunohistochemical staining and real-time polymerase chain reaction (PCR) were used to determine the expression of B7-H3 in clinical specimens. Clinical data were applied to survival analysis. Phosphoprotein was purified from cultured Patu8988 cells using the Phosphoprotein Purification Kit. Cell apoptosis was detected using propidium iodide–Annexin V staining to investigate the relation between the expression of B7-H3 and Patu8988 cells treated with gemcitabine. Western blot was used to determine the effect of B7-H3 on the expression of proteins including extracellular signal–regulated kinase (ERK)1/2, epidermal growth factor receptor (EGFR), and Inhibitor of NF-κB(IκB) in Patu8988 cells; B7-H3 was activated by 4H7, which as an agonist monoclonal antibody to B7-H3.

Results

The expression of B7-H3 was found to be higher in tumor tissues than in normal tissues of pancreatic carcinoma. Survival analysis revealed that patients in the low-B7-H3 expression group were likely to have a longer overall survival compared with those in the high-expression group (P < 0.05). B7-H3 activated by 4H7 could reduce gemcitabine-induced apoptosis in Patu8988 cells. Activation of B7-H3 by 4H7 induced variations in p-ERK1/2, EGFR, and IκB protein levels. When B7-H3 was upregulated, the expression levels of EGFR and p-ERK1/2 proteins significantly increased (P < 0.05), but the expression level of IκB significantly decreased (P < 0.05), especially in the gemcitabine-treated group.

Conclusion

This study demonstrated that B7-H3 could deliver signals to pancreatic cancer cells to combat apoptosis induced by gemcitabine.

A monoclonal antibody against CD86 and its protection in a murine lupus nephritis model of chronic graft-versus-host disease

CONTEXT

Lupus nephritis is the most common complication that causes the death of systemic lupus erythematosus patients. CD28/CTLA4 and their ligands CD80 or CD86 costimulatory pathway play a pivotal role in autoimmune disease and organ transplantation.

OBJECTIVES

We generated a monoclonal antibody (clone 1D1) against human CD86 (1D1) that could recognize both human and mouse CD86, and blocked the CD86/CD28 costimulatory pathway with our mAb on a murine lupus nephritis model induced with chronic graft-versus-host disease (cGVHD).

MATERIALS AND METHODS

Experimental lupus nephritis mice were induced with cGVHD, and splenocyte population were analyzed by flow cytometry. Autoantibodies and proteinuria were detected to evaluate the severity of lupus nephritis. The change of histopathology was observed by microscopy, fluorescence microscopy and electron microscopy.

RESULTS

we successfully generated a monoclonal antibody against human CD86(1D1). 1D1 mAb could recognize not only human CD86, but also mouse CD86. 1D1 was applied to the cGVHD-induced experimental lupus nephritis model, and our study found the production of ANA and anti-dsDNA in the 1D1-treated group was lower than those in IgG-treated group after four weeks. The pathological injure of kidney in the 1D1-treated group was lighten than that in IgG-treated group.

DISCUSSION AND CONCLUSIONS

Our data showed that blockade of CD86/CD28 with 1D1 induced a significant remission of proteinuria, production of autoantibodies, immune complex deposition and renal parenchyma lesions in experimental mice. Anti-CD86 Abs might be a potential method for immune therapy in autoimmune diseases and transplantation.

Anti-human CD138 monoclonal antibodies and their bispecific formats: generation and characterization

Syndecan-1 (CD138), a heparan sulfate proteoglycan, acts as a co-receptor for growth factors and chemokines and is a molecular marker associated with the epithelial-mesenchymal transition during development and carcinogenesis. In this study, we generated two specific mouse anti-human CD138 monoclonal antibodies (mAbs, clone ID: 480CT5.4.3, 587CT7.3.6.5) using hybridoma technology and identified their immunological characteristics. After hybridoma sequencing, the single-chain variable fragments (ScFvs) cloned from two hybridoma cells were combined with anti-CD3 OKT-3 ScFv to generate two recombinant bispecific antibodies (h-STL002, m-STL002) against CD138 and CD3 molecules, respectively. The bispecific antibodies were able to specifically target CD138 + multiple myeloma (MM) cells and CD3 + T cells, and showed the potent cytotoxicity against MM RPMI-8226 cell line through T cell activation. However, these bispecific antibodies without T cells did not cause toxic side effect on MM cells. Overall, the two hybridoma clones and their bispecific formats have great potential to promote diagnosis and immunotherapy of plasma cell malignancy.

Murine b7-h3 is a co-stimulatory molecule for T cell activation

The B7 family member B7-H3 (CD276) plays a key role during an immune response but its function remains controversial. In this study, we found that murine B7-H3 up-regulated the proliferation and cytokine production of T cells. Our study suggested that there was no interaction of murine B7-H3 with a triggering receptor expressed on myeloid cells (TREM)-like transcript 2 (TLT-2). Further studies demonstrated that mouse B7-H3 specifically bound to T cells and its receptor was not murine TLT-2. Moreover, murine B7-H3 was a positive co-stimulatory molecule in the regulation of T cell-mediated immune responses.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.

B7-H3 was highly expressed in human primary hepatocellular carcinoma and promoted tumor progression

B7-H3 has been detected in different cancers and correlated to tumor progression and outcome in cancer patients. In this study, we investigated the expression of B7-H3 in tissues and cells of primary hepatocellular carcinoma (PHC) patients. The research showed that B7-H3 is aberrantly expressed in PHC tissues and cells, and its high expression on HepG2 cells significantly promotes cell proliferation, adhesion, migration, and invasion capacity; moreover, it inhibits the proliferation of CD8(+) T cells. Thus, B7-H3 may have a critical role in PHC and it may enhance tumor escape from the immune surveillance of CD8(+) T cells.

Overexpression of B7-H3 in CD133+ colorectal cancer cells is associated with cancer progression and survival in human patients

Cancer stem-like cells are enriched in CD133-positive (CD133(+)) colorectal cancer (CRC) cells. To date, the biological significance of CD133 expression in cancer stem-like cells is still unknown. B7-H3, a costimulatory molecule, plays a pivotal role in tumor immune escape by inhibiting the functions of T cells. To identify a new marker to predict the tumor grade of CRC, we analyzed the expression of B7-H3 and CD133 in colorectal tumor samples, and their clinical significance was determined. By using a series of techniques including pathologic tissue microarray technology, immunohistochemistry, and immunofluorescent staining, we found B7-H3 was expressed in 56.73% of the CRC cases (59/104) sampled; CD133 was detected in 26.92% of the CRC cases (28/104) sampled. Further analysis indicated that 22 of these CD133(+) samples expressed B7-H3. We also found coexpression of CD133 and B7-H3 in tumor tissue samples (r = 0.321, P < 0.01). Moreover, in contrast to individual CD133 or B7-H3 expression, the coexpression of B7-H3 and CD133 was evidently associated with the depth of tumor invasion, lymphatic metastasis, distant metastasis, and Dukes' stage, suggesting it is a valuable biomarker for the progression of CRC. Indeed, the patients with coexpression of B7-H3 and CD133 had a poorer survival than the other patients (P < 0.05). In summary, our results reveal that B7-H3 was aberrantly expressed in CD133(+) CRC cells, and the expression level was closely associated with tumor progression.

Differentiation and activation of equine monocyte-derived dendritic cells are not correlated with CD206 or CD83 expression

Dendritic cells (DC) are the main immune mediators inducing primary immune responses. DC generated from monocytes (MoDC) are a model system to study the biology of DC in vitro, as they represent inflammatory DC in vivo. Previous studies on the generation of MoDC in horses indicated that there was no distinct difference between immature and mature DC and that the expression profile was distinctly different from humans, where CD206 is expressed on immature MoDC whereas CD83 is expressed on mature MoDC. Here we describe the kinetics of equine MoDC differentiation and activation, analysing both phenotypic and functional characteristics. Blood monocytes were first differentiated with equine granulocyte-macrophage colony-stimulating factor and interleukin-4 generating immature DC (iMoDC). These cells were further activated with a cocktail of cytokines including interferon-γ) but not CD40 ligand to obtain mature DC (mMoDC). To determine the expression of a broad range of markers for which no monoclonal antibodies were available to analyse the protein expression, microarray and quantitative PCR analysis were performed to carry out gene expression analysis. This study demonstrates that equine iMoDC and mMoDC can be distinguished both phenotypically and functionally but the expression pattern of some markers including CD206 and CD83 is dissimilar to the human system.

Silencing of B7-H3 increases gemcitabine sensitivity by promoting apoptosis in pancreatic carcinoma

In numerous types of cancer, the expression of a novel member of the B7 ligand family, the B7-H3 immunoregulatory protein, has been correlated with a poor prognosis. In the present study, we investigated the role of B7-H3 in chemoresistance in pancreatic carcinoma. Silencing of B7-H3, through lentivirus-mediated delivery of stable short hairpin RNA, was observed to increase the sensitivity of the human pancreatic carcinoma cell line Patu8988 to gemcitabine as a result of enhanced drug-induced apoptosis. Overexpression of B7-H3 caused the cancer cells to be more resistant to the drug. Subsequently, we investigated the underlying mechanisms of B7-H3-mediated gemcitabine resistance, and found that the levels of survivin decreased in cells in which B7-H3 had been knocked down. In vivo animal experiments demonstrated that tumors in which B7-H3 had been knocked down displayed a slower growth rate compared with the control xenografts. Notably, gemcitabine treatment led to a strong antitumor activity in mice with tumors in which B7-H3 had been knocked down; however, this effect was only marginal in the control group. Furthermore, survivin expression was weak in gemcitabine-treated tumors in which B7-H3 had been knocked down and apoptosis was increased, as revealed by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining. In summary, the present study demonstrated that B7-H3 induces gemcitabine resistance in pancreatic carcinoma cells, at least partially by downregulating survivin expression. These results provide novel insights into the function of B7-H3 and encourage the design and investigation of approaches targeting this protein in treating pancreatic carcinoma.

B7-H3 overexpression in pancreatic cancer promotes tumor progression

B7-H3, a member of the B7-family molecules, plays an important role in adaptive immune responses. In addition, B7-H3 is also expressed in several types of human cancers and is correlated with the poor outcome of cancer patients. However, its exact role in cancer is not known. In the present study, we compared B7-H3 expression in normal pancreas and pancreatic cancer tissue specimens, and determined the effects of low B7-H3 expression on the human pancreatic cancer cell line Patu8988 using lentivirus-mediated RNA interference. B7-H3 expression in pancreatic specimens was determined by enzyme-linked immunosorbent assay (ELISA). A Patu8988 cell line with low B7-H3 expression was established by lentivirus-mediated RNA interference to investigate the effect of B7-H3 on cell proliferation, migration and invasion in vitro. By establishing subcutaneous transplantation tumor and orthotopic transplantation pancreatic cancer mouse models, the effect of B7-H3 on cell proliferation, migration and invasion was studied in vivo. B7-H3 in tissue samples was significantly higher in the pancreatic cancer group than in the normal pancreas group (mean ± SD, 193.6±9.352 vs. 87.74±7.433 ng/g; P<0.0001). B7-H3 knockdown by RNA interference decreased cell migration and Transwell invasion up to 50% in vitro. No apparent impact was observed on cell proliferation in vitro. In the subcutaneous transplantation tumor mouse model, the tumor growth rate was reduced by the knockdown of B7-H3. In the orthotopic transplantation pancreatic cancer mouse model, the effect of inhibiting metastasis by knocking down B7-H3 was assessed in terms of the average postmortem abdominal visceral metastatic tumor weight. This demonstrated that inhibition of B7-H3 expression reduced pancreatic cancer metastasis in vivo. In conclusion, B7-H3 is aberrantly expressed in pancreatic cancer. In addition to modulating tumor immunity, B7-H3 may have a novel role in regulating pancreatic tumor progression.

Pancreatic ductal adenocarcinoma: a review of immunologic aspects

With the continued failures of both early diagnosis and treatment options for pancreatic cancer, it is now time to comprehensively evaluate the role of the immune system on the development and progression of pancreatic cancer. It is important to develop strategies that harness the molecules and cells of the immune system to treat this disease. This review will focus primarily on the role of immune cells in the development and progression of pancreatic ductal adenocarcinoma and to evaluate what is known about the interaction of immune cells with the tumor microenvironment and their role in tumor growth and metastasis. We will conclude with a brief discussion of therapy for pancreatic cancer and the potential role for immunotherapy. We hypothesize that the role of the immune system in tumor development and progression is tissue specific. Our hope is that better understanding of this process will lead to better treatments for this devastating disease.

Immunotherapy targets in pediatric cancer

Immunotherapy for cancer has shown increasing success and there is ample evidence to expect that progress gleaned in immune targeting of adult cancers can be translated to pediatric oncology. This manuscript reviews principles that guide selection of targets for immunotherapy of cancer, emphasizing the similarities and distinctions between oncogene-inhibition targets and immune targets. It follows with a detailed review of molecules expressed by pediatric tumors that are already under study as immune targets or are good candidates for future studies of immune targeting. Distinctions are made between cell surface antigens that can be targeted in an MHC independent manner using antibodies, antibody derivatives, or chimeric antigen receptors versus intracellular antigens which must be targeted with MHC restricted T cell therapies. Among the most advanced immune targets for childhood cancer are CD19 and CD22 on hematologic malignancies, GD2 on solid tumors, and NY-ESO-1 expressed by a majority of synovial sarcomas, but several other molecules reviewed here also have properties which suggest that they too could serve as effective targets for immunotherapy of childhood cancer.

Stimulation of B7-H3 (CD276) directs the differentiation of human marrow stromal cells to osteoblasts

Previous studies showed that B7-H3 (CD276), a cytokine involved in the activation of T lymphocytes, regulates murine bone formation. However, the role of B7-H3 in bone formation is barely understood. Herewith, we report, that stimulation of B7-H3 promotes the differentiation of human marrow stromal cells (hMSCs) to osteoblasts. With 4H7, a new monoclonal antibody against human B7-H3, we have identified B7-H3 is located on the surface of human marrow stromal cells. Evermore, we have found that increase of B7-H3 levels are correlated with the differentiation course of hMSCs. Stimulation of B7-H3 with 4H7 antibody considerably increases the numbers of osteoblasts generated from the hMSCs in the presence of inducing medium containing dexamethasone, sodium β-glycerophosphate and l-ascorbic acid. 4H7 treatments significantly increase osteoblast markers including alkaline phosphatase (ALP), and osteocalcin (OC) after day 7 and day 14 of the inducing hMSCs differentiation. The numbers of mineralized nodules of osteoblasts have been remarkly increased after 21 days of induced differentiation of hMSCs. However, stimulation effects of 4H7 antibody on membrane B7-H3 has been eliminated by addition of B7-H3Fc fusion protein. These results indicate 4H7 antibody specifically stimulates the membrane B7-H3 and directs the differentiation of hMSCs. Furthermore, our study also shows that stimulation of B7-H3 increases the expression of osteoprotein (OPG), and decreases the expression of its cognate ligand, the receptor activator of nuclear factor kappaB ligand (RANKL).

Detection and quantitation of soluble B7-H3 in expressed prostatic secretions: a novel marker in patients with chronic prostatitis

PURPOSE

We determined the soluble B7-H3 level and its clinical significance in serum and expressed prostatic secretions of patients with chronic prostatitis, including chronic bacterial prostatitis (type II) and chronic pelvic pain syndrome.

MATERIALS AND METHODS

Using enzyme-linked immunosorbent assay we measured soluble B7-H3 in 11 patients with chronic prostatitis (type II), and 26 with inflammatory (type IIIA) and 54 with noninflammatory (type IIIB) chronic pelvic pain syndrome, and healthy donors. We assessed differences between these groups using Student's t test. As determined by the National Institutes of Health-Chronic Prostatitis Symptom Index, we correlated soluble B7-H3 with clinical pain using the Pearson test.

RESULTS

We found no significant difference between serum soluble B7-H3 in healthy donors and patients with chronic prostatitis (p = 0.897). However, soluble B7-H3 in expressed prostatic secretions was statistically significantly decreased in patients with chronic prostatitis vs controls (p <0.001). ROC using soluble B7-H3 greater than 38.82 ng/ml in expressed prostatic secretions distinguished patients with chronic prostatitis from healthy donors with 90.9% sensitivity and 83.5% specificity. Also, soluble B7-H3 levels in expressed prostatic secretions correlated negatively with the Chronic Prostatitis Symptom Index and the pain subscore. Compared to the pretreatment level soluble B7-H3 in expressed prostatic secretions was significantly increased in patients with a greater than 25% decrease in the Chronic Prostatitis Symptom Index total score (p = 0.016).

CONCLUSIONS

Data indicate that the soluble B7-H3 level in expressed prostatic secretions is a novel chronic prostatitis marker that correlates negatively with subjective symptoms.

Clinical importance of B7-H3 expression in human pancreatic cancer

Background:

B7-H3 is a new member of the B7 ligand family and regulates T-cell responses in various conditions. However, the role of B7-H3 in tumour immunity is largely unknown. The purpose of this study was to evaluate the clinical significance of B7-H3 expression in human pancreatic cancer and the therapeutic potential for cancer immunotherapy.

Methods:

We investigated B7-H3 expression in 59 patients with pancreatic cancer by immunohistochemistry and real-time PCR. Furthermore, we examined the anti-tumour effect of B7-H3-blocking monoclonal antibody in vivo in a murine pancreatic cancer model.

Results:

Tumour-related B7-H3 expression was abundant in most human pancreatic cancer tissues and was significantly higher compared with that in non-cancer tissue or normal pancreas. Moreover, its expression was significantly more intense in cases with lymph node metastasis and advanced pathological stage. B7-H3 blockade promoted CD8⁺ T-cell infiltration into the tumour and induced a substantial anti-tumour effect on murine pancreatic cancer. In addition, the combination of gemcitabine with B7-H3 blockade showed a synergistic anti-tumour effect without overt toxicity.

Conclusion:

Our data show for the first time that B7-H3 may have a critical role in pancreatic cancer and provide the rationale for developing a novel cancer immunotherapy against this fatal disease.

Soluble CD276 (B7-H3) is released from monocytes, dendritic cells and activated T cells and is detectable in normal human serum

Expression of membrane CD276 (mB7-H3) has been reported on dendritic cells (DCs), monocytes, activated T cells, and various carcinoma cells. However, reports concerning its in vivo function have been inconsistent. Moreover, whether there is a soluble form of this protein is not known. In this study, using a sensitive dual monoclonal antibody sandwich enzyme-linked immunosorbent assay (ELISA) to detect the soluble form of B7-H3 (sB7-H3), we demonstrated the release of sB7-H3 by monocytes, DCs, activated T cells, and various mB7-H3+ but not mB7-H3- carcinoma cells. Release from cells was blocked by addition of a matrix metalloproteinase inhibitor (MMPI), which concomitantly caused the accumulation of B7-H3 on the cell surface. To determine the level of circulating sB7-H3, more than 200 serum samples were included in the study. The results indicated that sB7-H3 was present at high levels in all serum samples. Western blotting of sB7-H3 from cell culture supernatants or sera of healthy donors indicated that the molecular size was approximately 16 kDa. Soluble B7-H3 was able to bind to the B7-H3 receptor (B7-H3R) on activated T cells, which showed that sB7-H3 is a functionally active form. These results indicate that release of sB7-H3 from the cell surface is mediated by a matrix metalloproteinase and probably regulates B7-H3R/B7-H3 interactions in vivo. Cleavage of sB7-H3 to an active soluble form would alter both proximal and distal cellular responses.

4IgB7-H3 is the major isoform expressed on immunocytes as well as malignant cells

Human B7-H3, a novel member of B7 family, has two isoforms (2IgB7-H3 and 4IgB7-H3). As costimulatory functions of both isoforms are not clarified, there has been much discussion on their expression patterns, T-cell responses, etc. This study generated two specific mouse anti-human 2IgB7-H3 monoclonal antibodies (mAbs) (7D7 and 10F1), whose specificities are quite different from those of the available B7-H3 mAb (21D4) by competition assay. The use of antibodies indicated that B7-H3 was found to have different expression patterns on monocyte-derived dendritic cells, that is the isoform 2IgB7-H3 is tended to express on immature dendritic cells (iDCs), whereas 4IgB7-H3 could be detected in the whole process of maturation of dendritic cells. The isoform 4IgB7-H3 was shown in the immunohistochemistry assay to be more widely expressed than 2IgB7-H3 in human benign and malignant hepatic tissues. Furthermore, flow cytometry and reverse transcription-polymerase chain reaction indicated that 4IgB7-H3 rather than 2IgB7-H3 was the major isoform on many human tumor cell lines. In addition, both 2IgB7-H3- and 4IgB7-H3-transfected cells could promote T-cell proliferation, which could be blocked by 7D7 mAb. These two novel antibodies may shed light on the function of the two B7-H3 isoforms.

Distinct expression and inhibitory function of B and T lymphocyte attenuator on human T cells

B and T lymphocyte attenuator (BTLA) has been recently identified as a new inhibitory receptor of the CD28 superfamily, with similarities to cytotoxic T lymphocyte activation antigen (CTLA)-4 and programmed death (PD)-1. Engagement of BTLA on T lymphocytes can profoundly reduce the T cell receptor (TCR)-mediated activation. In this study, we generated four monoclonal antibodies (mAbs) against human BTLA. Using the produced mAb 8H9, the BTLA molecule was found to distinctly express on many subgroups of immunocytes and show a regulatory expression, which was in accordance with its unique ligand herpes virus entry mediator (HVEM) in the process of T cell activation. In addition, the expression of BTLA was increased in the CD4(+) and CD8(+) T cells of pleural fluid in lung cancer patients. Furthermore, we showed that the BTLA-induced negative signals could be triggered by mAb 7D7. Cross-linking of BTLA with mAb 7D7 suppressed T lymphocyte proliferation, downregulated the expression of T cell activation marker CD25, and inhibited the production of interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10.

Characterization and application of two novel monoclonal antibodies against human OX40: costimulation of T cells and expression on tumor as well as normal gland tissues

OX40, a membrane-bound molecule of the tumor-necrosis-factor-receptor superfamily, is a critical costimulatory receptor during the immune response. Here, we newly generated two specific mouse antihuman OX40 monoclonal antibodies (mAbs) (2G2 and 1F7), whose specificities are quite different from the available OX40 mAb (ACT35) by competition assay. It was also found that both mAbs could enhance the proliferation, activation and differentiation of T lymphocytes primed by anti-CD3 mAb. These results evidenced that both were functional antihuman OX40 mAbs. Furthermore, stained by 2G2 and 1F7, FCM and immunohistochemistry detected the constitutive expression of OX40 on tumor cell lines from epithelium, breast cancer and glioma tissues. Meanwhile, the non-tumor tissues (thyroid gland, stomach gland) were also found OX40 expression. These results suggested that OX40 is not only expressed in activated T cells, but also in some tumors as well as normal gland tissues. Such expression pattern indicated that OX40 may be a valuable surface antigen in unveiling its expression and function outside the immune system. Briefly, these novel antibodies may contribute to the evaluation of the mechanism of tumor metastasis and eventually shed light on further study of tumor immunotherapy and autoimmune diseases.