T cell retargeting with MHC class I-restricted antibodies: the CD28 costimulatory domain enhances antigen-specific cytotoxicity and cytokine production

T cells require both primary and costimulatory signals for optimal activation. The primary Ag-specific signal is delivered by engagement of the TCR. The second Ag-independent costimulatory signal is mediated by engagement of the T cell surface costimulatory molecule CD28 with its target cell ligand B7. However, many tumor cells do not express these costimulatory molecules. We previously constructed phage display derived F(AB), G8, and Hyb3, Ab-based receptors with identical specificity but distinct affinities for HLA-A1/MAGE-A1, i.e., "TCR-like" specificity. These chimeric receptors comprised the FcepsilonRI-gamma signaling element. We analyzed whether linking the CD28 costimulation structure to it (gamma + CD28) could affect the levels of MHC-restricted cytolysis and/or cytokine production. Human scFv-G8(POS) T lymphocytes comprising the gamma + CD28 vs the gamma signaling element alone produced substantially more IL-2, TNF-alpha, and IFN-gamma in response to HLA-A1/MAGE-A1(POS) melanoma cells. Also a drastic increase in cytolytic capacity of scFv-G8(POS) T cells, equipped with gamma + CD28 vs the gamma-chain alone was observed

Virtual screening for inhibitors of the human TSLP:TSLPR interaction

The pro-inflammatory cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathophysiology of various allergy disorders that are mediated by type 2 helper T cell (Th2) responses, such as asthma and atopic dermatitis. TSLP forms a ternary complex with the TSLP receptor (TSLPR) and the interleukin-7-receptor subunit alpha (IL-7Ra), thereby activating a signaling cascade that culminates in the release of pro-inflammatory mediators. In this study, we conducted an in silico characterization of the TSLP: TSLPR complex to investigate the drugability of this complex. Two commercially available fragment libraries were screened computationally for possible inhibitors and a selection of fragments was subsequently tested in vitro. The screening setup consisted of two orthogonal assays measuring TSLP binding to TSLPR: a BLI-based assay and a biochemical assay based on a TSLP: alkaline phosphatase fusion protein. Four fragments pertaining to diverse chemical classes were identified to reduce TSLP: TSLPR complex formation to less than 75% in millimolar concentrations. We have used unbiased molecular dynamics simulations to develop a Markov state model that characterized the binding pathway of the most interesting compound. This work provides a proof-ofprinciple for use of fragments in the inhibition of TSLP: TSLPR complexation

Drift of the HIV-1 envelope glycoprotein gp120 toward increased neutralization resistance over the course of the epidemic: a comprehensive study using the most potent and broadly neutralizing monoclonal antibodies

Extending our previous analyses to the most recently described broadly neutralizing monoclonal antibodies (bNAbs) we confirm a drift of HIV-1 clade B variants over two decades toward higher resistance to bNAbs targeting almost all the identified gp120 neutralizing epitopes. In contrast, the sensitivity to bNAbs targeting the gp41 MPER remained stable, suggesting a selective pressure on gp120 preferentially. Despite this evolution, selected combinations of bNAbs remain capable to neutralize efficiently most of the circulating variants

Chronic Delivery of Antibody Fragments Using Immunoisolated Cell Implants as a Passive Vaccination Tool

BACKGROUND: Monoclonal antibodies and antibody fragments are powerful biotherapeutics for various debilitating diseases. However, high production costs, functional limitations such as inadequate pharmacokinetics and tissue accessibility are the current principal disadvantages for broadening their use in clinic. METHODOLOGY AND PRINCIPAL FINDINGS: We report a novel method for the long-term delivery of antibody fragments. We designed an allogenous immunoisolated implant consisting of polymer encapsulated myoblasts engineered to chronically release scFv antibodies targeted against the N-terminus of the Aβ peptide. Following a 6-month intracerebral therapy we observed a significant reduction of the production and aggregation of the Aβ peptide in the APP23 transgenic mouse model of Alzheimer's disease. In addition, functional assessment showed prevention of behavioral deficits related to anxiety and memory traits. CONCLUSIONS AND SIGNIFICANCE: The chronic local release of antibodies using immunoisolated polymer cell implants represents an alternative passive vaccination strategy in Alzheimer's disease. This novel technique could potentially benefit other diseases presently treated by local and systemic antibody administration

Prostate tumor attenuation in the nu/nu murine model due to anti-sarcosine antibodies in folate-targeted liposomes

Herein, we describe the preparation of liposomes with folate-targeting properties for the encapsulation of anti-sarcosine antibodies (antisarAbs@LIP) and sarcosine (sar@LIP). The competitive inhibitory effects of exogenously added folic acid supported the role of folate targeting in liposome internalization. We examined the effects of repeated administration on mice PC-3 xenografts. Sar@LIP treatment significantly increased tumor volume and weight compared to controls treated with empty liposomes. Moreover, antisarAbs@LIP administration exhibited a mild antitumor effect. We also identified differences in gene expression patterns post-treatment. Furthermore, Sar@LIP treatment resulted in decreased amounts of tumor zinc ions and total metallothioneins. Examination of the spatial distribution across the tumor sections revealed a sarcosine-related decline of the MT1X isoform within the marginal regions but an elevation after antisarAbs@LIP administration. Our exploratory results demonstrate the importance of sarcosine as an oncometabolite in PCa. Moreover, we have shown that sarcosine can be a potential target for anticancer strategies in management of PCa

Immunotherapy with FBTA05 (Bi20), a trifunctional bispecific anti-CD3 x anti-CD20 antibody and donor lymphocyte infusion (DLI) in relapsed or refractory B-cell lymphoma after allogeneic stem cell transplantation: study protocol of an investigator-driven, open-label, non-randomized, uncontrolled, dose-escalating Phase I/II-trial

BACKGROUND: Patients with B cell malignancies refractory to allogeneic stem cell transplantation (SCT) can be treated by subsequent immunotherapy with donor lymphocyte infusions (DLI). But unlike myeloid leukemia, B cell leukemia and lymphoma are less sensitive to allogeneic adoptive immunotherapy. Moreover, the beneficial graft-versus-lymphoma (GVL) effect may be associated with moderate to severe graft-versus-host disease (GVHD). Thus, novel therapeutic approaches augmenting the anti-tumor efficacy of DLI and dissociating the GVL effect from GVHD are needed. The anti-CD20 x anti-CD3 trifunctional bispecific antibody (trAb) FBTA05 may improve the targeting of tumor cells by redirecting immune allogeneic effector cells while reducing the risk of undesirable reactivity against normal host cells. Hence, FBTA05 may maximize GVL effects by simultaneously decreasing the incidence and severity of GVHD. METHODS/DESIGN: Based on this underlying treatment concept and on promising data taken from preclinical results and a small pilot study, an open-label, non-randomized, uncontrolled, dose-escalating phase I/II-study is conducted to evaluate safety and preliminary efficacy of the investigational antibody FBTA05 in combination with DLI for patients suffering from rituximab- and/or alemtuzumab-refractory, CD20-positive low- or high-grade lymphoma after allogeneic SCT. During the first trial phase with emphasis on dose escalation a maximum of 24 patients distributed into 4 cohorts will be enrolled. For the evaluation of preliminary efficacy data a maximum of 12 patients (6 patients with low-grade lymphoma and/or Chronic Lymphocytic Leukemia (CLL) / 6 patients with high-grade or aggressive lymphoma) will attend the second phase of this clinical trial. DISCUSSION: Promising data (e.g. induction of cellular immunity; GVL predominance over GVHD; achievement of partial or complete responses; prolongation of time-to-progression) obtained from this phase I/II trial would represent the first milestone in the clinical evaluation of a novel immunotherapeutic concept for treatment-resistant low- and high-grade lymphoma and NHL patients in relapse. TRIAL REGISTRATION: NCT0113857

Author Correction:Single human B cell-derived monoclonal anti-Candida antibodies enhance phagocytosis and protect against disseminated candidiasis

We thank the BBSRC, SULSA BioSKAPE and Pfizer Inc. for funding for a studentship for F.M.R. and the Wellcome Trust (086827, 075470, 099215, 099197 and 101873) and a Wellcome Trust ISSF award (105625), MRC CiC (MC_PC_14114) and MRC Centre for Medical Mycology and University of Aberdeen for funding and a Wellcome Trust Strategic Award (097377) and a Wellcome Trust grant 099197MA to T.F. and FCT Investigator IF/00033/2012 and PTDC/QUI-QUI/112537/2009 to A.S.P. We thank Ian Broadbent, Angus McDonald and Ron Gladue for constructive discussions; Chris Boston and Amanda Fitzgerald for advice on antibody expression and purification; Ed Lavallie and Wayne Stochaj for design and expression of the recombinant Hyr1; Louise Walker for high-pressure freezing of samples for TEM analysis; Jeanette Wagener for endotoxin testing of mAbs for in vivo experiments; Yan Liu of the Glycosciences laboratory for insight in the analysis with N-glycan array; Rebecca Hall and Mark Gresnigt for providing fungal strains; Andrew Limper and Theodore J. Kottom for providing Pneumocystis infected lung tissue extracts; David Williams for C. albicans mannoprotein; Christopher Thornton for A. fumigatus mannoprotein; Katie J. Doores for mAb PGT 128; and Gordon Brown for the murine Fc-Dectin-1. We are grateful to Lucinda Wight, Debbie Wilkinson and Kevin MacKenzie in the Microscopy and Histology Core Facility (Aberdeen University) and Raif Yuecel in the Iain Fraser Cytometry Centre (Aberdeen University) for their expert help with microscopy and cytometry experiments. We are also grateful to the staff at the University of Aberdeen Medical Research Facility for assistance with in vivo experiments and members of the Glycosciences Laboratory for their support of the Carbohydrate Microarray Facility. 18 January 2019 - Author Correction: Single human B cell-derived monoclonal anti-Candida antibodies enhance phagocytosis and protect against disseminated candidiasis F. M. Rudkin, I. Raziunaite, H. Workman, S. Essono, R. Belmonte, D. M. MacCallum, E. M. Johnson, L. Silva, A. S. Palma, T. Feizi, A. Jensen, L. P. Erwig & N. A. R. Gow Nature Communicationsvolume 10, Article number: 394 (2019)Peer reviewedPublisher PD