Immunohistochemical Expression of Lymphatic Endothelial Markers in Blue Rubber Bleb Nevus Syndrome.

INTRODUCTION: Blue rubber bleb nevus syndrome (BRBNS) is an uncommon vascular anomaly characterized by multifocal cutaneous, visceral, and other soft tissue or solid organ venous malformations. We observed that BRBNS lesions express immunohistochemical markers of lymphatic differentiation. METHODS: BRBNS histopathologic specimens assessed at our institution during the past 27 years were reviewed. Slides from 19 BRBNS lesions were selected from 14 patients (9 cutaneous, 9 gastrointestinal, and 1 hepatic). We recorded the involved anatomical compartments and presence/absence of thrombi or vascular smooth muscle. Immunohistochemical endothelial expression of PROX1 (nuclear) and D2-40 (membranous/cytoplasmic) was evaluated semi-quantitatively. RESULTS: Endothelial PROX1 immunopositivity was noted in all specimens; the majority (89.5%) demonstrated staining in more than 10% of cells. D2-40 immunopositivity was present in one-third (33%) of cutaneous lesions and only 1 gastrointestinal lesion. CONCLUSION: Endothelial cells in BRBNS almost always express 1 or more immunohistochemical markers of lymphatic differentiation.

Expression of Claudin-4 and D2-40 and their significance in prostatic adenocarcinoma.

BACKGROUND: Claudins are a clan of proteins that are the most important component of tight junctions. The claudin-4 expression has been linked to tumour cell invasion and progression in a variety of primary malignancies. Evaluation of lymphovascular density (LVD) correlates with tumour aggressiveness and may correlate with prognosis. D2-40 is a highly specific marker of lymphatic vessels. AIMS: To evaluate the claudin-4 expression in relation to LVD by D2-40 expression and with clinicopathological parameters in prostatic adenocarcinoma. SETTINGS AND DESIGN: Prospective study. MATERIALS AND METHODS: 39 cases of prostatic adenocarcinoma were taken, the D2-40 and claudin-4 immunohistochemical stains were performed and correlation was done with clinicopathological parameters. STATISTICAL ANALYSIS USED: Statistical analyses such as mean, median, standard deviation, Mann-Whitney U test, Fischer exact test, Spearman's rank-order correlation coefficient, Chi-square test and T-test were used. RESULTS: The claudin-4 expression was seen higher in cases with higher Gleason score but it was statistically non-significant (P = 0.778). The claudin-4 expression did not correlate with any clinicopathological parameters. LVD in the peritumoral area was significantly higher as compared to the intratumoral area (P = 0.005). Intratumoral LVD and perineural invasion were found to be statistically significant (P = 0.048). CONCLUSION: The claudin-4 expression may correlate with adverse prognostic parameters. Higher lymphatic vessels can be responsible for the higher metastatic potential of prostatic adenocarcinomas.

Epitope Recognition of a Monoclonal Antibody Raised against a Synthetic Glycerol Phosphate Based Teichoic Acid.

Glycerol phosphate (GroP)-based teichoic acids (TAs) are antigenic cell-wall components found in both enterococcus and staphylococcus species. Their immunogenicity has been explored using both native and synthetic structures, but no details have yet been reported on the structural basis of their interaction with antibodies. This work represents the first case study in which a monoclonal antibody, generated against a synthetic TA, was developed and employed for molecular-level binding analysis using TA microarrays, ELISA, SPR-analyses, and STD-NMR spectroscopy. Our findings show that the number and the chirality of the GroP residues are crucial for interaction and that the sugar appendage contributes to the presentation of the backbone to the binding site of the antibody.

Reevaluation of lymphovascular invasion in gastric cancer using endothelial markers D2-40 and EVG: Enhanced detection, better predictor of lymph node metastasis and biological aggressiveness.

BACKGROUND AND OBJECTIVES: The diagnosis of lymphovascular invasion (LVI) is often inaccurate with routine histology. This study aimed to evaluate the use of immunohistochemistry (IHC) in detecting LVI and reevaluate the clinical implications of LVI in gastric cancer. METHODS: This prospective unrandomized cohort study analyzed the rates of LVI positivity and its relevance with other clinicopathologic features. RESULTS: Between November 2017 and April 2018, 558 patients undergoing curative gastrectomy were enrolled and assigned to the IHC group (n = 285) and hematoxylin-eosin group (n = 273). The use of IHC increased the rates of LVI positivity (60.8% vs. 43.3%, p < .001) and decreased the rates of undetermined LVI subtype (7.7% vs. 27.1%, p < .001). The LVI-negative patients identified by IHC had fewer lymph node metastases (16.8% vs. 34.6%, p = .002) and earlier pathological stage (p = .004) than those identified by routine histology. The LVI-positive patients identified by IHC had a higher percentage of perineural invasion (p = .019). CONCLUSIONS: The use of endothelial markers significantly enhanced the detection of LVI. The LVI detected by IHC could be a better predictor of lymph node metastasis and biological aggressiveness in gastric cancer.

Immunophenotypic Differences in Tumor-Infiltrating Lymphocytes and Neovascularization Between Primary Cutaneous Melanoma With and Without Metastasis: An Immunohistochemical Study of 80 Cases.

ABSTRACT: The prognostic implications of the immunophenotype of the tumor-infiltrating lymphocytes (TILs) in primary cutaneous melanoma are well known. In recent years, the study of this immunophenotype has also resulted in immunotherapeutic consequences. The aims of this study were to characterize the subpopulations of TILs in primary cutaneous melanoma, in cases with and without metastasis, as well as the neovascularization associated with the primary neoplasm, and its influence on the development of metastasis. To this end, the immunophenotype of TILs and the neovascularization of 80 patients with primary cutaneous melanoma (40 each with metastatic and non-metastatic melanoma) were analyzed by immunohistochemistry for CD3, CD4, CD8, FOXP3, PD-1, CD31, and D2-40 antibodies. We found that higher frequencies of TILs with brisk pattern, and CD4+, CD8+, and CD20+ cells in TILs, and a lower frequency of CD31+ vessels were histopathological features associated with better prognosis in primary cutaneous melanoma. Our results support the notion that the immunohistochemical study of TILs and neovascularization in primary cutaneous melanoma may be helpful tools for identifying patients at increased risk of metastasis development.

Distant cutaneous metastasis of malignant epithelioid mesothelioma.

Malignant mesothelioma is a locally aggressive malignancy most commonly arising from the pleural and/or peritoneal cavity. Distant cutaneous metastasis is extremely rare. Here, we describe two cases of mesothelioma metastatic to the head and neck skin. Case 1: A 64-year-old man diagnosed previously with extensive thoracic and abdominal mesothelioma, developed a rapidly growing right upper lip lesion, for which a wedge resection was performed. Case 2: A 77-year-old woman with a history of pleural mesothelioma developed a firm, mobile subcutaneous nodule on the right lateral forehead, clinically thought to represent either an epidermal inclusion cyst or a lipoma. A punch biopsy was performed. In both cases, histopathologic evaluation revealed dermal proliferation of epithelioid cells with moderate cytologic atypia and three mitotic figures per mm2 and two mitotic figures per mm2 for Cases 1 and 2, respectively. Immunohistochemical studies revealed the lesional cells to be positive for WT1, mesothelin, D2-40, CK5/6, while being negative for melanocytic and other keratinocytic markers, supporting a diagnosis of metastatic mesothelioma. Awareness of rare instances of cutaneous metastases from malignant mesothelioma is necessary to avoid possible misdiagnosis and ensure appropriate management.

Binding of omeprazole to protein targets identified by monoclonal antibodies.

Omeprazole is the most commonly used proton pump inhibitor (PPI), a class of medications whose therapeutic mechanism of action involves formation of a disulfide linkage to cysteine residues in the H+/K+ ATPase pump on gastric secretory cells. Covalent linkage between the sole sulfur group of omeprazole and selected cysteine residues of the pump protein results in inhibition of acid secretion in the stomach, an effect that ameliorates gastroesophageal reflux and peptic ulcer disease. PPIs, though useful for specific conditions when used transiently, are associated with diverse untoward effects when used long term. The mechanisms underlying these potential off-target effects remain unclear. PPIs may, in fact, interact with non-canonical target proteins (non-pump molecules) resulting in unexpected pathophysiological effects, but few studies describe off-target PPI binding. Here, we describe successful cloning of monoclonal antibodies against protein-bound omeprazole. We developed and used monoclonal antibodies to characterize the protein target range of omeprazole, stability of omeprazole-bound proteins, and the involvement of cysteines in binding of omeprazole to targets. We demonstrate that a wide range of diverse proteins are targeted by omeprazole. Protein complexes, detected by Western blotting, are resistant to heat, detergents, and reducing agents. Reaction of omeprazole occurs with cysteine-free proteins, is not fully inhibited by cysteine alkylation, occurs at neutral pH, and induces protein multimerization. At least two other clinically used PPIs, rabeprazole and tenatoprazole, are capable of binding to proteins in a similar fashion. We conclude that omeprazole binds to multiple proteins and is capable of forming highly stable complexes that are not dependent on disulfide linkages between the drug and protein targets. Further studies made possible by these antibodies may shed light on whether PPI-protein complexes underlie off-target untoward effects of chronic PPI use.

Measuring the affinity of protein-protein interactions on a single-molecule level by mass photometry.

Measurements of biomolecular interactions are crucial to understand the mechanisms of the biological processes they facilitate. Bulk-based methods such as ITC and SPR provide important information on binding affinities, stoichiometry, and kinetics of interactions. However, the ensemble averaging approaches are not able to probe the intrinsic heterogeneity often displayed by biological systems. Interactions that involve cooperativity or result in the formation of multicomponent complexes pose additional experimental challenges. Single-molecule techniques have previously been applied to solve these problems. However, single-molecule experiments are often technically demanding and require labeling or immobilization of the molecules under study. A recently developed single-molecule method, mass photometry (MP), overcomes these limitations. Here we applied MP to measure the affinities of biomolecular interactions. We have demonstrated how MP allows the user to study multivalent complexes and quantify the affinities of different binding sites in a single measurement. Results obtained from this single-molecule technique have been validated by ITC and BLI. The quality and information content of the MP data, combined with simple and fast measurements and low sample consumption makes MP a new preferred method for measuring strong protein-protein interactions.

A high sensitivity ZENK monoclonal antibody to map neuronal activity in Aves.

The transcription factor ZENK is an immediate early gene that has been employed as a surrogate marker to map neuronal activity in the brain. It has been used in a wide variety of species, however, commercially available antibodies have limited immunoreactivity in birds. To address this issue we generated a new mouse monoclonal antibody, 7B7-A3, raised against ZENK from the rock pigeon (Columba livia). We show that 7B7-A3 labels clZENK in both immunoblots and histological stainings with high sensitivity and selectivity for its target. Using a sound stimulation paradigm we demonstrate that 7B7-A3 can detect activity-dependent ZENK expression at key stations of the central auditory pathway of the pigeon. Finally, we compare staining efficiency across three avian species and confirm that 7B7-A3 is compatible with immunohistochemical detection of ZENK in the rock pigeon, zebra finch, and domestic chicken. Taken together, 7B7-A3 represents a useful tool for the avian neuroscience community to map functional activity in the brain.

Prognostic significance of immunohistochemical markers in adrenocortical carcinoma.

Background: To present basic demographic and clinical characteristics of patients with adrenocortical carcinoma (ACC), to determine the overall survival rate and to analyze the results of immunohistochemical staining and its correlation with the length of survival.Material and methods: The study was conducted during the period between 1996 and 2010 and included 30 patients with ACC. Immunohistochemical staining (MMP9, melan A, inhibin, caltretinin, D2-40, synaptophysin and Ki-67) was performed.Results: ACC was diagnosed in 19 females and 11 men (1.7:1). The average age was 50.1 years. The median tumor size was 10 cm, the median weight 400 g. Majority of subjects had positive immunohistochemical staining for the markers of interest. Patients with any negative staining had shorter cancer-specific survival than ones with positive staining. According to the log-rank test results as well as according to the results of the univariate Cox analysis, negative staining for inhibin, D2-40 and synaptophysin and Ki-67 expression ≥7% were associated with poorer prognosis.Conclusions: The results of our study suggest that the absence of staining for some immunohistochemical markers and increased expression of Ki-67 are associated with a poorer prognosis and shorter survival of patients with ACC. Immunohistochemical markers may serve as a prognostic factor for ACC.

TAFRO syndrome as a cause of glomerular microangiopathy: a case report and literature review.

BACKGROUND: TAFRO syndrome is a systemic inflammatory disorder that manifests as thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R), and organomegaly (O). Renal dysfunction is frequently complicated with TAFRO syndrome, however, it is challenging to perform kidney biopsy in patients with TAFRO syndrome in the presence of thrombocytopenia. Renal histology in TAFRO syndrome mainly shows membranoproliferative glomerulonephritis (MPGN)-like lesions or thrombotic microangiopathy (TMA)-like glomerulopathy. We review our case and previous reports of TAFRO syndrome with kidney biopsy findings and discuss the renal pathophysiology of TAFRO syndrome. CASE PRESENTATION: We describe a previously healthy 48- year-old woman with TAFRO syndrome. Kidney biopsy performed before the treatment showed diffuse global endocapillary proliferative changes with endothelial cell swelling, double contours of partial capillary walls, and mesangiolysis, consistent with TMA-like glomerulopathy. Glucocorticoid therapy including steroid pulse was ineffective and she developed anasarca, renal dysfunction and oliguria. Hemodialysis was required. However, the anti-Interleukin (IL)-6 receptor antibody (tocilizumab) therapy was very effective. An increase in urinary volume was achieved about 2 weeks after the tocilizumab therapy and hemodialysis was discontinued. To investigate the renal pathophysiology of TAFRO syndrome, we performed immunohistological staining of vascular endothelial growth factor (VEGF)-A, CD34, and D2-40, in our case and a normal control kidney. Glomerular VEGF-A was especially positive in podocytes both, in the control and in the case, with no significant difference and there was a significant increase of VEGF-A staining area in the cortical peritubular capillaries in the case. Both glomerular and renal cortical CD34 expression were significantly decreased in our case. D2-40 expression in cortex was not significantly different. CONCLUSIONS: We reviewed our case and other 10 previous reports about renal biopsy findings in TAFRO syndrome and found that glomerular microangiopathy was a common finding. IL-6-VEGF-axis-induced glomerular microangiopathy may play a crucial role in developing acute kidney injury in TAFRO syndrome and the anti-IL-6 receptor antibody therapy may be useful for TAFRO syndrome refractory to glucocorticoids. About the pathophysiology of VEGF in TAFRO syndrome, VEGF balance in the glomerulus and perhaps in the peritubular capillary system as well may be critical. Further investigation is needed.

Prognostic value of blood and lymphatic vessel markers in tongue cancer: A systematic review.

Tongue squamous cell carcinoma (TSCC) has a poor prognosis due to its early metastasis through blood and lymphatic vessels. We undertook a systematic review to investigate the prognostic significance of blood microvessel density (MVD) and lymphatic vessel density (LVD) in TSCC patients. We carried out a systematic search in Ovid Medline, Scopus, and Cochrane libraries. All studies that evaluated the prognostic significance of MVD/LVD markers in TSCC were systematically retrieved. Our results showed that MVD/LVD markers, CD31, CD34, CD105, factor VIII, lymphatic vessel endothelial hyaluronan receptor-1, and D2-40 were evaluated in TSCC patients until 28 June 2018. Six out of 13 studies reported markers that were associated with poor prognosis in TSCC. Two out of three studies suggested that a high number of D2-40+ vessels predicated low overall survival (OS); the third study reported that the ratio of D2-40+ over factor VIII+ vessels is associated with low OS. Most of the other markers had controversial results for prognostication. We found higher expression of MVD/LVD markers were commonly, but not always, associated with shorter survival in TSCC patients. It is therefore not currently possible to recommend implementation of these markers as reliable prognosticators in clinical practice. More studies (especially for D2-40) with larger patient cohorts are needed.

ITCH-dependent proteasomal degradation of c-FLIP induced by the anti-HER3 antibody 9F7-F11 promotes DR5/caspase 8-mediated apoptosis of tumor cells.

BACKGROUND: HER3/ErbB3 receptor deletion or blockade leads to tumor cell apoptosis, whereas its overexpression confers anti-cancer drug resistance through upregulation of protective mechanisms against apoptosis. We produced the anti-HER3 antibody 9F7-F11 that promotes HER3 ubiquitination and degradation via JNK1/2-dependent activation of the E3 ubiquitin ligase ITCH, and that induces apoptosis of cancer cells. Cellular FLICE-like inhibitory protein (c-FLIP) is a key regulator of apoptotic pathways. Here, we wanted to determine the mechanisms underlying the pro-apoptotic effect of 9F7-F11. METHODS: Anti-HER3 antibody-induced apoptosis was assessed by western blot, and by flow cytometry measurement of Annexin V/7-AAD-labelled tumor cells (BxPC3, MDA-MB-468 and DU145 cell lines). c-FLIP/ITCH interaction and subsequent degradation/ubiquitination were investigated by co-immunoprecipitation of ITCH-silenced vs scramble control cells. The relationship between ITCH-mediated c-FLIP degradation and antibody-induced apoptosis was examined by western blot and flow cytometry of tumor cells, after ITCH RNA interference or by pre-treatment with ITCH chemical inhibitor chlorimipramine (CI). RESULTS: Following incubation with 9F7-F11, cancer cell apoptosis occurs through activation of caspase-8, - 9 and - 3 and the subsequent cleavage of poly (ADP-ribose) polymerase (PARP). Moreover we showed that ubiquitination and proteasomal degradation of the anti-apoptotic protein c-FLIP was mediated by USP8-regulated ITCH recruitment. This effect was abrogated by ITCH- and USP8-specific RNA interference (siRNA), or by the ITCH chemical inhibitor CI. Specifically, ITCH silencing or CI blocked 9F7-F11-induced caspase-8-mediated apoptosis of tumor cells, and restored c-FLIP expression. ITCH-silencing or CI concomitantly abrogated HER3-specific antibody-induced apoptosis of Annexin V/7-AAD-labelled BxPC3 cells. 9F7-F11 favored the extrinsic apoptosis pathway by inducing TRAIL-R2/DR5 upregulation and TRAIL expression that promoted the formation of death-inducing signaling complex (DISC), leading to caspase-8-mediated apoptosis. Incubation with 9F7-F11 also induced BID cleavage, BAX upregulation and BIM expression, which initiated the caspase-9/3-mediated mitochondrial death pathway. The anti-HER3 antibody pro-apoptotic effect occurred concomitantly with downregulation of the pro-survival proteins c-IAP2 and XIAP. CONCLUSIONS: The allosteric non-neuregulin competing modulator 9F7-F11, sensitizes tumor cells to DR5/caspase-8-mediated apoptosis through ITCH-dependent downregulation of c-FLIP.

Developing an Antibody-Drug Conjugate Approach to Selective Inhibition of an Extracellular Protein.

Antibody-drug conjugates (ADCs) are a growing class of therapeutics that harness the specificity of antibodies and the cell-killing potency of small-molecule drugs. Beyond cytotoxics, there are few examples of the application of an ADC approach to difficult drug discovery targets. Here, we present the initial development of a non-internalising ADC, with a view to selectively inhibiting an extracellular protein. Employing the wellinvestigated matrix metalloproteinase-9 (MMP-9) as our model, we adapted a broad-spectrum, nonselective MMP inhibitor for conjugation and linked this to a MMP-9-targeting antibody. The resulting ADC fully inhibits MMP-9, and ELISA results suggest antibody targeting can direct a nonselective inhibitor.

Subtle Changes in the Combining Site of the Chlamydiaceae-Specific mAb S25-23 Increase the Antibody-Carbohydrate Binding Affinity by an Order of Magnitude.

Murine antibodies S25-23, S25-26, and S25-5 derive from a common germ-line origin, and all bind the Chlamydiaceae family-specific epitope αKdo(2→8)αKdo(2→4)αKdo (where Kdo is 3-deoxy-α-d- manno-oct-2-ulosonic acid) with high affinity and specificity. These antibodies recognize the entire trisaccharide antigen in a linkage-dependent manner via a groove composed largely of germ-line residues. Despite sharing identical heavy and light chain genes, S25-23 binds the family-specific epitope with nanomolar affinity, which is an order of magnitude higher than that of S25-26, while S25-5 displays an affinity between those of S25-23 and S25-26. We determined the high-resolution crystal structures of S25-23 and S25-5 antigen binding fragments in complex with a pentasaccharide derived from the LPS of Chlamydia and measured the affinity of S25-5 for chlamydial LPS antigens using isothermal titration microcalorimetry. The 1.75 Å resolution structure of S25-23 shows how subtle conservative mutations Arg(L)-27E to lysine and Ser(H)-56 to threonine lead to an order of magnitude increase in affinity. Importantly, comparison between previous S25-26 structures and the 1.99 and 2.05 Å resolution liganded and unliganded structures of S25-5, respectively, shows how a Ser(L)-27E mutation results in an intermediate affinity due to the reduced enthalpic penalty associated with complex formation that would otherwise be required for arginine in this position. This strategy allows for subtle adjustments in the combining site via affinity maturation that have dramatic consequences for the affinity of an antibody for its antigen.

Immunohistochemical characterization of lymphangiogenesis-related biomarkers in primary and recurrent gliomas: A STROBE compliant article.

Glial tumors constitute the majority of primary intracranial brain tumors. The expression of specific markers of lymphangiogenesis in gliomas still remains unclear.A total of 40 surgical specimens from 20 patients with recurrent gliomas were included in the study. The expression of D2-40, vascular endothelial growth factor (VEGF)-C, VEGF-D, and VEGF receptor-3 (VEGR-3) was detected by immunohistochemistry (IHC). The clinicopathologic data (p53 and Ki67) were also collected and analyzed.At relapse malignant transformation rate was 65% (13/20 cases). D2-40, VEGF-C, VEGF-D, and VEGFR-3 were expressed in 20%, 30%, 60%, and 20% of primary and 45%, 30%, 75%, and 35% of recurrent glioma tumors (P < .01, P = 1.00, P = .03, P = .03). In 13 cases with increased malignancy grade, the expression of Ki67 and p53 were higher at relapse compared with the primary tumors (P = .001, P = .045). Multivariate survival analysis showed VEGF-D was an independent prognostic factor for malignant transformation (HR = 0.376, P = .045).Glioma is easy to relapse with tumor progression. VEGF-D was an independent prognostic factor for malignant transformation.

Durable targeting of B-lymphocytes in living mice.

Transfer to and enduring expression of genes in B cells has proved a vexing challenge. We report here a novel method for the specific and durable targeting of B lymphocytes in living mice. The method involves generation of lentiviruses pseudotyped with an anti-CD19 antibody. CD19 targeting viruses injected in the spleen of living mice efficiently transduced B cells and plasma cells detected by flow cytometry analysis of GFP expression. Expression of the reporter gene could be detected in the intact animal by external imaging for more than a year and was enhanced by booster immunization. Our method thus enables the specific delivery, expression and localization by external imaging of exogenous genes to the B cells and plasma cells of living individuals.

Development of Mouse Monoclonal Antibodies Against Human Amyloid Fibril Proteins for Diagnostic and Research Purposes.

Commercial antibodies against varying proteins are often not optimal for identification of proteins in their amyloid fibril forms. Reasons can be the different conformation but also a variety of modifications like N- or C-terminal truncation. Therefore, development of own monoclonal antibodies against amyloid fibril proteins may be advantageous. This chapter gives suggestions of how to be successful in such approaches.

Vascular endothelial growth factors C and D and lymphangiogenesis at the early stage of esophageal squamous cell carcinoma progression.

We conducted a detailed study of lymphangiogenesis and subsequent lymph node metastasis in early-stage esophageal squamous cell carcinoma (ESCC) using immunostaining for D2-40 and vascular endothelial growth factor (VEGF)-C and D. The study materials included 13 samples of normal squamous epithelium, 6 samples of low-grade intraepithelial neoplasia (LGIN), and 60 samples of superficial ESCC (M1 and M2 cancer 24; M3 or deeper cancer 36). We assessed lymphatic vessel density (LVD) using D2-40 and immunoreactivity for VEGF-C and D in relation to histological type, lymphatic invasion, and lymph node metastasis. LVD in M1 and M2 lesions and M3 or deeper lesions was significantly higher than in normal squamous epithelium (P < 0.001). High expression of VEGF-C and D was observed in M1 and M2 cancer and in M3 or deeper cancer, but not in normal squamous epithelium or LGIN. LVD in VEGF-C- and D-positive cases was significantly higher than in negative cases (P < 0.001). In M3 or deeper cancer, the correlation between VEGF-C or D status and lymphatic invasion or lymph node metastasis was not significant. LVD in cases with positive lymphatic invasion and those with lymph node metastasis was significantly higher than in cases lacking either (P = 0.02 and 0.03, respectively). ESCC cells produce VEGF-C and D from the very early stage of progression. VEGF-C and D activate lymphangiogenesis, and this increase of lymphatic vessels leads to lymphatic invasion and subsequent lymph node metastasis.

An immunologically relevant rodent model demonstrates safety of therapy using a tumour-specific IgE.

BACKGROUND: Designing biologically informative models for assessing the safety of novel agents, especially for cancer immunotherapy, carries substantial challenges. The choice of an in vivo system for studies on IgE antibodies represents a major impediment to their clinical translation, especially with respect to class-specific immunological functions and safety. Fcε receptor expression and structure are different in humans and mice, so that the murine system is not informative when studying human IgE biology. By contrast, FcεRI expression and cellular distribution in rats mirror that of humans. METHODS: We are developing MOv18 IgE, a human chimeric antibody recognizing the tumour-associated antigen folate receptor alpha. We created an immunologically congruent surrogate rat model likely to recapitulate human IgE-FcεR interactions and engineered a surrogate rat IgE equivalent to MOv18. Employing this model, we examined in vivo safety and efficacy of antitumour IgE antibodies. RESULTS: In immunocompetent rats, rodent IgE restricted growth of syngeneic tumours in the absence of clinical, histopathological or metabolic signs associated with obvious toxicity. No physiological or immunological evidence of a "cytokine storm" or allergic response was seen, even at 50 mg/kg weekly doses. IgE treatment was associated with elevated serum concentrations of TNFα, a mediator previously linked with IgE-mediated antitumour and antiparasitic functions, alongside evidence of substantially elevated tumoural immune cell infiltration and immunological pathway activation in tumour-bearing lungs. CONCLUSION: Our findings indicate safety of MOv18 IgE, in conjunction with efficacy and immune activation, supporting the translation of this therapeutic approach to the clinical arena.