Combination of two monoclonal antibodies with SOCS1 N- and C-terminal binding sites to address SOCS1 status in B cells and B-cell lymphoma.

Introduction: Accumulating studies show that the tumour suppressor SOCS1 is one of the most frequently mutated genes in lymphomas, often affecting the coding sequence of SOCS1 protein. Depending on the type of mutation and lymphoma concerned, SOCS1 mutations have different impacts on progression-free and overall survival. Two antibodies binding the N and C terminals of SOCS1 would be a suitable 'test pair' to identify truncated versions of SOCS1.

Co-Stimulatory Bispecific Antibodies Induce Enhanced T Cell Activation and Tumor Cell Killing in Breast Cancer Models.

Although T cell-recruiting CD3-binding bispecific antibodies (BiMAb) have been proven to be clinically effective for hematologic malignancies, the success of BiMAb targeting solid tumor-associated antigens (TAA) in carcinomas so far remains poor. We reasoned that provision of co-stimulatory BiMAb in combination with αTAA-αCD3 BiMAb would boost T cell activation and proliferative capacity, and thereby facilitate the targeting of weakly or heterogeneously expressed tumor antigens. Various αTAA-αCD3 and αTAA-αCD28 BiMAb in a tetravalent IgG1-Fc based format have been analyzed, targeting multiple breast cancer antigens including HER2, EGFR, CEA, and EpCAM.

A new reliable and highly specific monoclonal antibody to detect the C-terminal region of silencer of cytokine signaling 1.

Introduction: SOCS1, a negative regulator of JAK/STAT signaling, is among the most frequently mutated genes in DLBCL and classical Hodgkin lymphoma. The C-terminal SOCS box domain, mediating the degradation of phospho-JAK2, is often affected or even lacking. The analysis of such variants is hampered by the lack of a SOCS1-specific monoclonal antibody recognizing the C-terminus of SOCS1.

High-density Peptide Arrays Help to Identify Linear Immunogenic B-cell Epitopes in Individuals Naturally Exposed to Malaria Infection.

High-density peptide arrays are an excellent means to profile anti-plasmodial antibody responses. Different protein intrinsic epitopes can be distinguished, and additional insights are gained, when compared with assays involving the full-length protein. Distinct reactivities to specific epitopes within one protein may explain differences in published results, regarding immunity or susceptibility to malaria.

Tubular Dickkopf-3 promotes the development of renal atrophy and fibrosis.

Renal tubular atrophy and interstitial fibrosis are common hallmarks of etiologically different progressive chronic kidney diseases (CKD) that eventually result in organ failure. Even though these pathological manifestations constitute a major public health problem, diagnostic tests, as well as therapeutic options, are currently limited. Members of the dickkopf (DKK) family, DKK1 and -2, have been associated with inhibition of Wnt signaling and organ fibrosis.

A novel method for measuring cellular antibody uptake using imaging flow cytometry reveals distinct uptake rates for two different monoclonal antibodies targeting L1.

Monoclonal antibodies (mAbs) have emerged as a promising tool for cancer therapy. Differing approaches utilize mAbs to either deliver a drug to the tumor cells or to modulate the host's immune system to mediate tumor kill. The rate by which a therapeutic antibody is being internalized by tumor cells is a decisive feature for choosing the appropriate treatment strategy.

Self-Antigen Presentation by Keratinocytes in the Inflamed Adult Skin Modulates T-Cell Auto-Reactivity.

Keratinocytes have a pivotal role in the regulation of immune responses, but the impact of antigen presentation by these cells is still poorly understood, particularly in a situation where the antigen will be presented only in adult life. Here, we generated a transgenic mouse model in which keratinocytes exclusively present a myelin basic protein (MBP) peptide covalently linked to the major histocompatibility complex class II β-chain, solely under inflammatory conditions. In these mice, inflammation caused by epicutaneous contact sensitizer treatment resulted in keratinocyte-mediated expansion of MBP-specific CD4(+) T cells in the skin.

Dickkopf-3, a tissue-derived modulator of local T-cell responses.

The adaptive immune system protects organisms from harmful environmental insults. In parallel, regulatory mechanisms control immune responses in order to assure preservation of organ integrity. Yet, molecules involved in the control of T-cell responses in peripheral tissues are poorly characterized.

A photosensitizer delivered by bispecific antibody redirected T lymphocytes enhances cytotoxicity against EpCAM-expressing carcinoma cells upon light irradiation.

Recently conducted clinical trials have provided impressive evidence that chemotherapy resistant metastatic melanoma and several hematological malignancies can be cured using adoptive T cell therapy or T cell-recruiting bispecific antibodies. However, a significant fraction of patients did not benefit from these treatments. Here we have evaluated the feasibility of a novel combination therapy which aims to further enhance the killing potential of bispecific antibody-redirected T lymphocytes by using these cells as targeted delivery system for photosensitizing agents.

Acinar cell carcinomas of the pancreas: a molecular analysis in a series of 57 cases.

Pancreatic acinar cell carcinomas (PACs) are rare but are distinct aggressive neoplasms that phenotypically differ from pancreatic ductal adenocarcinomas (PDACs) and pancreatic neuroendocrine neoplasms (PNENs). Despite recent work on the genetic changes of PACs, their molecular pathogenesis is still poorly understood. In this study, we focus on a comparative genomic hybridization analysis.

Antibody therapy to human L1CAM in a transgenic mouse model blocks local tumor growth but induces EMT.

L1 cell adhesion molecule (L1CAM) is overexpressed in many human cancers, confers bad prognosis and augments cell motility, invasion and metastasis. Results from xenograft mouse models suggested that L1CAM antibodies might be promising tools for cancer therapy. Here, we generated human L1CAM-transgenic mice to study therapeutic efficacy and putative side effects in a model system.

Lack of CD24 expression in mice reduces the number of leukocytes in the colon.

CD24 is an extensively glycosylated membrane protein that is linked to the membrane via a glycosyl-phosphatidylinositol (GPI)-anchor. In mice, CD24 is expressed by hematopoietic and non-hematopoietic cells. CD24-/- mice do not have gross immunological defects, but detailed analysis revealed strongly reduced responses in an experimental autoimmune encephalomyelitis (EAE) model and a massive proliferation of T cells under lymphopenic conditions.

Metalloprotease-mediated tumor cell shedding of B7-H6, the ligand of the natural killer cell-activating receptor NKp30.

Natural killer (NK) cells are potent immune effector cells capable of mediating antitumor responses. Thus, during immunoediting, tumor cell populations evolve strategies to escape NK-cell-mediated recognition. In this study, we report a novel mechanism of immune escape involving tumor cell shedding of B7-H6, a ligand for the activating receptor NKp30 that mediates NK-cell binding and NK-cell-mediated killing.

Immunotherapy of B-cell non-Hodgkin lymphoma by targeting the chemokine receptor CXCR5 in a preclinical mouse model.

Bispecific antibodies are promising agents for immunotherapy. Here, we describe a quadroma-based trifunctional bispecific antibody binding the chemokine receptor CXCR5 and the T-cell antigen CD3 that efficiently prevents tumor growth in a mouse B-cell lymphoma model. CXCR5 regulates the tissue homeostasis of mature B cells and is highly expressed on B-cell non-Hodgkin and lymphocyte-predominant Hodgkin lymphoma, as well as on a subset of CD4(+) T cells known as follicular T-helper cells.

Neurofibromin specific antibody differentiates malignant peripheral nerve sheath tumors (MPNST) from other spindle cell neoplasms.

Malignant peripheral nerve sheath tumors (MPNST) derive from the Schwann cell or perineurial cell lineage and occur either sporadically or in association with the tumor syndrome neurofibromatosis type 1 (NF1). MPNST often pose a diagnostic challenge due to their frequent lack of pathognomonic morphological or immunohistochemical features. Mutations in the NF1 tumor suppressor gene are found in all NF1-associated and many sporadic MPNST.

L1 cell adhesion molecule as a potential therapeutic target in murine models of endometriosis using a monoclonal antibody approach.

Background/aims: The neural cell adhesion molecule L1CAM is a transmembrane glycoprotein abnormally expressed in tumors and previously associated with cell proliferation, adhesion and invasion, as well as neurite outgrowth in endometriosis. Being an attractive target molecule for antibody-based therapy, the present study assessed the ability of the monoclonal anti-L1 antibody (anti-L1 mAb) to impair the development of endometriotic lesions in vivo and endometriosis-associated nerve fiber growth.

Methods And Results: Endometriosis was experimentally induced in sexually mature B6C3F1 (n=34) and CD-1 nude (n=21) mice by autologous and heterologous transplantation, respectively, of endometrial fragments into the peritoneal cavity.

Generation of “LYmph Node Derived Antibody Libraries” (LYNDAL) for selecting fully human antibody fragments with therapeutic potential.

The development of efficient strategies for generating fully human monoclonal antibodies with unique functional properties that are exploitable for tailored therapeutic interventions remains a major challenge in the antibody technology field. Here, we present a methodology for recovering such antibodies from antigen-encountered human B cell repertoires. As the source for variable antibody genes, we cloned immunoglobulin G (IgG)-derived B cell repertoires from lymph nodes of 20 individuals undergoing surgery for head and neck cancer.

A standardized staining protocol for L1CAM on formalin-fixed, paraffin-embedded tissues using automated platforms.

The L1 cell adhesion molecule (L1CAM) is overexpressed in many human cancers and can serve as a biomarker for prognosis in most of these cancers (including type I endometrial carcinomas). Here we provide an optimized immunohistochemical staining procedure for a widely used automated platform (VENTANA™), which has recourse to commercially available primary antibody and detection reagents. In parallel, we optimized the staining on a semi-automated BioGenix (i6000) 
immunostainer.

Downregulation of the activating NKp30 ligand B7-H6 by HDAC inhibitors impairs tumor cell recognition by NK cells.

Natural killer (NK) cells are central effector cells during innate immune responses against cancer. Natural cytotoxicity receptors expressed by NK cells such as NKp30 are involved in the recognition of transformed cells. Recently, the novel B7 family member B7-H6, which is expressed on the cell surface of various tumor cells including hematological malignancies, was identified as an activating ligand for NKp30.

Hypoxia induces EMT in low and highly aggressive pancreatic tumor cells but only cells with cancer stem cell characteristics acquire pronounced migratory potential.

Tumor hypoxia induces epithelial-mesenchymal transition (EMT), which induces invasion and metastasis, and is linked to cancer stem cells (CSCs). Whether EMT generates CSCs de novo, enhances migration of existing CSCs or both is unclear. We examined patient tissue of pancreatic ductal adenocarcinoma (PDA) along with carcinomas of breast, lung, kidney, prostate and ovary.

Combining forces to hit cancer stem cells: TRAIL-lymphocytes and EpCAMxCD3 bispecific antibody show efficacy against pancreatic cancer.

TRAIL selectively kills cancer cells while bispecific antibody EpCAMxCD3 guides effector lymphocytes to cancer cells. Arming of ex vivo constructed TRAIL-lymphocytes with EpCAMxCD3 enhances contact time and affinity between lymphocytes and tumor cells and enforces tumor elimination. This boosts endogenous immune responses and augments the effect of cytotoxic tumor therapy.

CD24 controls Src/STAT3 activity in human tumors.

CD24 is a glycosyl-phosphatidylinositol-anchored membrane protein that is frequently over-expressed in a variety of human carcinomas and is correlated with poor prognosis. In cancer cell lines, changes of CD24 expression can alter several cellular properties in vitro and tumor growth in vivo. However, little is known about how CD24 mediates these effects.

Therapeutic potential of amanitin-conjugated anti-epithelial cell adhesion molecule monoclonal antibody against pancreatic carcinoma.

Background: Human epithelial cell adhesion molecule (EpCAM) is overexpressed in many cancers. Anti-EpCAM antibodies have shown promise in preclinical studies, but showed no tumor regression in a recent phase II clinical trial. Therefore, we generated a novel anti-EpCAM antibody-drug conjugate and assessed whether it showed enhanced antitumor effects.

Detection of circulating tumor-associated antigen depends on the domains recognized by the monoclonal antibodies used: N-terminal trimmed EpCAM-levels are much higher than untrimmed forms.

The measurement of tumor-associated proteins is of high diagnostic value in the follow-up of cancer patients. Most tests ignore that various forms of the protein can exist; especially in epithelial cancers and the soluble receptors they produce. We choose EpCAM as model-antigen to analyze whether tests recognizing different domains of the protein give different results in patients' sera.