Detailed bladder cancer immunoprofiling reveals new clues for immunotherapeutic strategies.

Objectives: Bladder cancer (BlCa) is the tenth most frequent malignancy worldwide and the costliest to treat and monitor. Muscle-invasive BlCa (MIBC) has a dismal prognosis, entailing the need for alternative therapies for the standard radical cystectomy. Checkpoint blockade immunotherapy has been approved for high-grade non-muscle-invasive BlCa (HG NMIBC) and metastatic disease, but its effectiveness in localised MIBC remains under scrutiny. Herein, we sought to characterise and compare the immune infiltrate of HG NMIBC and MIBC samples, including ICOS expression, a targetable immune checkpoint associated with regulatory T cell(Tregs)-mediated immunosuppression. Methods: Immunohistochemistry for CD83, CD20, CD68, CD163, CD3, CD8, CD4, FoxP3/ICOS and PD-L1 was performed in HG NMIBC and MIBC samples (n = 206), and positive staining was quantified in the peritumoral and/or intratumoral tissue compartments with QuPath imaging software. Results: CD20+ B cells, CD68+ and CD163+ tumor-associated macrophages were significantly increased in MIBCs and associated with poor prognosis. In turn, higher infiltration of T cells was associated with prolonged survival, with exception of the CD4+ helper subset. Intratumoral expression of CD3 and CD8 was independent prognostic factors for increased disease-free survival (DFS) in multivariable analysis. Remarkably, Tregs (FoxP3+/FoxP3+ICOS+) were found differentially distributed between tissue compartments. PD-L1 immunoexpression independently predicted a shorter DFS and associated with higher infiltration of FoxP3+ICOS+ Tregs. Conclusions: Immune infiltrates of HG NMIBC and MIBC display significant differences that may help selecting patients for immunotherapies. Considering ICOS immunoexpression results, it might constitute a relevant therapeutic target, eventually in combination with anti-PD-1/PD-L1 therapies, for certain BlCa patient subsets.

ICOS-Positive Regulatory T Cells in Hepatocellular Carcinoma: The Perspective from Digital Pathology Analysis.

INTRODUCTION: Inducible co-stimulator (ICOS), an important co-stimulatory receptor on effector T cells (Teffs), may also contribute to tumor growth due to its high expression on regulatory T cells (Tregs). This study explored the clinical significance of ICOS-expressing Tregs in hepatocellular carcinoma (HCC). METHODS: Tumor tissues from HCC patients who received curative hepatectomy were obtained at a referral center. Dual immunohistochemistry was performed to evaluate the expression of ICOS and Foxp3. The cell densities and proximities between stained cells in regions of interest were measured by digital pathology and the associations with clinical outcome were analyzed. RESULTS: A total of 142 patients (male:female = 112: 30, median age of 61.0 years) were enrolled. Among them, 87 (61.3%) had chronic hepatitis B virus infection and 33 (23.2%) had chronic hepatitis C infection. Low α-fetoprotein level (<20 ng/mL) and early-stage were significantly associated with improved overall survival (OS). The density of ICOS+Foxp3+ cells and the ratio of ICOS+Foxp3+/total Foxp3+ cells were significantly higher (p < 0.001) in the tumor center than in the peritumor area. Patients with a high density of ICOS+Foxp3+ cells or a high ratio of ICOS+Foxp3+/total Foxp3+ cells in the tumor center trended to have a shorter OS. A shorter distance between ICOS+Foxp3+ cells and ICOS+Foxp3- cells (likely Teffs) in the tumor center was significantly associated with a shorter OS (p = 0.030), suggesting active immunosuppression of ICOS+ Tregs on ICOS+ Teffs. CONCLUSION: An increased abundance of ICOS+ Tregs in the tumor center in comparison to the peritumor area indicates a strong immunosuppressive tumor microenvironment of HCC. A high proportion of ICOS+Foxp3+ cells and a shorter distance between ICOS+ Tregs and other ICOS+ cells were associated with a poor OS, suggesting that depleting ICOS+ Tregs might provide clinical benefit for patients with HCC.

Novel Bispecific Antibody for Synovial-Specific Target Delivery of Anti-TNF Therapy in Rheumatoid Arthritis.

Biologic drugs, especially anti-TNF, are considered as the gold standard therapy in rheumatoid arthritis. However, non-uniform efficacy, incidence of infections, and high costs are major concerns. Novel tissue-specific agents may overcome the current limitations of systemic administration, providing improved potency, and safety. We developed a bispecific antibody (BsAb), combining human arthritic joint targeting, via the synovial-specific single-chain variable fragment (scFv)-A7 antibody, and TNFα neutralization, via the scFv-anti-TNFα of adalimumab, with the binding/blocking capacity comparable to adalimumab -immunoglobulin G (IgG). Tissue-targeting capacity of the BsAb was confirmed on the human arthritic synovium in vitro and in a synovium xenograft Severe combined immune deficient (SCID) mouse model. Peak graft accumulation occurred at 48 h after injection with sustained levels over adalimumab-IgG for 7 days and increased therapeutic effect, efficiently decreasing tissue cellularity, and markers of inflammation with higher potency compared to the standard treatment. This study provides the first description of a BsAb capable of drug delivery, specifically to the disease tissue, and a strong evidence of improved therapeutic effect on the human arthritic synovium, with applications to other existing biologics.

A fully human anti-BMP6 antibody reduces the need for erythropoietin in rodent models of the anemia of chronic disease.

Recombinant erythropoietin (EPO) and iron substitution are a standard of care for treatment of anemias associated with chronic inflammation, including anemia of chronic kidney disease. A black box warning for EPO therapy and concerns about negative side effects related to high-dose iron supplementation as well as the significant proportion of patients becoming EPO resistant over time explains the medical need to define novel strategies to ameliorate anemia of chronic disease (ACD). As hepcidin is central to the iron-restrictive phenotype in ACD, therapeutic approaches targeting hepcidin were recently developed. We herein report the therapeutic effects of a fully human anti-BMP6 antibody (KY1070) either as monotherapy or in combination with Darbepoetin alfa on iron metabolism and anemia resolution in 2 different, well-established, and clinically relevant rodent models of ACD. In addition to counteracting hepcidin-driven iron limitation for erythropoiesis, we found that the combination of KY1070 and recombinant human EPO improved the erythroid response compared with either monotherapy in a qualitative and quantitative manner. Consequently, the combination of KY1070 and Darbepoetin alfa resulted in an EPO-sparing effect. Moreover, we found that suppression of hepcidin via KY1070 modulates ferroportin expression on erythroid precursor cells, thereby lowering potentially toxic-free intracellular iron levels and by accelerating erythroid output as reflected by increased maturation of erythrocyte progenitors. In summary, we conclude that treatment of ACD, as a highly complex disease, becomes more effective by a multifactorial therapeutic approach upon mobilization of endogenous iron deposits and stimulation of erythropoiesis.

High-throughput assessment of the antibody profile in ovarian cancer ascitic fluids.

The identification of effective biomarkers for early diagnosis, prognosis, and response to treatments remains a challenge in ovarian cancer (OC) research. Here, we present an unbiased high-throughput approach to profile ascitic fluid autoantibodies in order to obtain a tumor-specific antigen signature in OC. We first reported the reactivity of immunoglobulins (Igs) purified from OC patient ascites towards two different OC cell lines. Using a discovery set of Igs, we selected tumor-specific antigens from a phage display cDNA library. After biopanning, 700 proteins were expressed as fusion protein and used in protein array to enable large-scale immunoscreening with independent sets of cancer and noncancerous control. Finally, the selected antigens were validated by ELISA. The initial screening identified eight antigenic clones: CREB3, MRPL46, EXOSC10, BCOR, HMGN2, HIP1R, OLFM4, and KIAA1755. These antigens were all validated by ELISA in a study involving ascitic Igs from 153 patients (69 with OC, 34 with other cancers and 50 without cancer), with CREB3 showing the highest sensitivity (86.95%) and specificity (98%). Notably, we were able to identify an association between the tumor-associated (TA) antibody response and the response to a first-line tumor treatment (platinum-based chemotherapy). A stronger association was found by combining three antigens (BCOR, CREB3, and MRLP46) as a single antibody signature. Measurement of an ascitic fluid antibody response to multiple TA antigens may aid in the identification of new prognostic signatures in OC patients and shift attention to new potentially relevant targets.

Novel in vitro booster vaccination to rapidly generate antigen-specific human monoclonal antibodies.

Vaccines remain the most effective tool to prevent infectious diseases. Here, we introduce an in vitro booster vaccination approach that relies on antigen-dependent activation of human memory B cells in culture. This stimulation induces antigen-specific B cell proliferation, differentiation of B cells into plasma cells, and robust antibody secretion after a few days of culture. We validated this strategy using cells from healthy donors to retrieve human antibodies against tetanus toxoid and influenza hemagglutinin (HA) from H1N1 and newly emergent subtypes such as H5N1 and H7N9. Anti-HA antibodies were cross-reactive against multiple subtypes, and some showed neutralizing activity. Although these antibodies may have arisen as a result of previous influenza infection, we also obtained gp120-reactive antibodies from non-HIV-infected donors, indicating that we can generate antibodies without prior antigenic exposure. Overall, our novel approach can be used to rapidly produce therapeutic antibodies and has the potential to assess the immunogenicity of candidate antigens, which could be exploited in future vaccine development.

Selecting soluble/foldable protein domains through single-gene or genomic ORF filtering: structure of the head domain of Burkholderia pseudomallei antigen BPSL2063.

The 1.8 Å resolution crystal structure of a conserved domain of the potential Burkholderia pseudomallei antigen and trimeric autotransporter BPSL2063 is presented as a structural vaccinology target for melioidosis vaccine development. Since BPSL2063 (1090 amino acids) hosts only one conserved domain, and the expression/purification of the full-length protein proved to be problematic, a domain-filtering library was generated using ß-lactamase as a reporter gene to select further BPSL2063 domains. As a result, two domains (D1 and D2) were identified and produced in soluble form in Escherichia coli. Furthermore, as a general tool, a genomic open reading frame-filtering library from the B. pseudomallei genome was also constructed to facilitate the selection of domain boundaries from the entire ORFeome. Such an approach allowed the selection of three potential protein antigens that were also produced in soluble form. The results imply the further development of ORF-filtering methods as a tool in protein-based research to improve the selection and production of soluble proteins or domains for downstream applications such as X-ray crystallography.

An Air-Well sparging minifermenter system for high-throughput protein production.

BACKGROUND: Over the last few years High-Throughput Protein Production (HTPP) has played a crucial role for functional proteomics. High-quality, high yield and fast recombinant protein production are critical for new HTPP technologies. Escherichia coli is usually the expression system of choice in protein production thanks to its fast growth, ease of handling and high yields of protein produced. Even though shake-flask cultures are widely used, there is an increasing need for easy to handle, lab scale, high throughput systems. RESULTS: In this article we described a novel minifermenter system suitable for HTPP. The Air-Well minifermenter system is made by a homogeneous air sparging device that includes an air diffusion system, and a stainless steel 96 needle plate integrated with a 96 deep well plate where cultures take place. This system provides aeration to achieve higher optical density growth compared to classical shaking growth without the decrease in pH value and bacterial viability. Moreover the yield of recombinant protein is up to 3-fold higher with a considerable improvement in the amount of full length proteins. CONCLUSIONS: High throughput production of hundreds of proteins in parallel can be obtained sparging air in a continuous and controlled manner. The system used is modular and can be easily modified and scaled up to meet the demands for HTPP.

Phage display technology for human monoclonal antibodies.

During the last 15 years in vitro technologies opened powerful routes to combine the generation of large libraries together with fast selection procedures to identify lead candidates. One of the commonest methods is based on the use filamentous phages. Antibodies (Abs) can be displayed successfully on the surface of phage by fusing the coding sequence of the antibody variable (V) regions to the phage minor coat protein pIII. By creating large libraries, antibodies with affinities comparable to those obtained using traditional hybridomas technology can be selected by a series of cycles of selection on antigen. As in this system antibody genes are cloned simultaneously with selection they can be easily further engineered for example by increasing their affinity (to levels unobtainable in the immune system), modulating their specificity or their effector function (by recloning into a full-length immunoglobulin scaffold). This chapter describes the basic protocols for antibody library construction, handling, and selection.

Profiling celiac disease antibody repertoire.

The aim of this study was to dissect the autoantibody response in celiac disease (CD) that remains largely unknown, with the goal of identifying the disease-specific autoantigenic protein pattern or the so called epitome. Sera from CD patients were used to select immunoreactive antigens from a cDNA phage-display library. Candidate genes were identified, the corresponding proteins produced and their immunoreactivity validated with sera from CD patients and controls. Thirteen CD-specific antigens were identified and further validated by protein microarray. The specificity for 6 of these antigens was confirmed by ELISA. Furthermore we showed that this antibody response was not abolished on a gluten free diet and was not shared with other autoimmune diseases. These antigens appear to be CD specific and independent of gluten induction. The utility of this panel extends beyond its diagnostic value and it may drive the attention to new targets for unbiased screens in autoimmunity research.