Daniel Baty - Academia.edu (original) (raw)

Papers by Daniel Baty

OncoImmunology, 2020

The natural killer group 2 member D (NKG2D) receptor is a C-type lectin-like activating receptor ... more The natural killer group 2 member D (NKG2D) receptor is a C-type lectin-like activating receptor mainly expressed by cytotoxic immune cells including NK, CD8 + T, γδ T and NKT cells and in some pathological conditions by a subset of CD4 + T cells. It binds a variety of ligands (NKG2DL) whose expressions is finely regulated by stress-related conditions. The NKG2DL/NKG2D axis plays a central and complex role in the regulation of immune responses against diverse cellular threats such as oncogene-mediated transformations or infections. We generated a panel of seven highly specific anti-human NKG2D single-domain antibodies targeting various epitopes. These single-domain antibodies were integrated into bivalent and bispecific antibodies using a versatile plug-and-play Fab-like format. Depending on the context, these Fab-like antibodies exhibited activating or inhibitory effects on the immune response mediated by the NKG2DL/NKG2D axis. In solution, the bivalent anti-NKG2D antibodies that compete with NKG2DL potently blocked the activation of NK cells seeded on immobilized MICA, thus constituting antagonizing candidates. Bispecific anti-NKG2DxHER2 antibodies that concomitantly engage HER2 on tumor cells and NKG2D on NK cells elicited cytotoxicity of unstimulated NK in a tumor-specific manner, regardless of their apparent affinities and epitopes. Importantly, the bispecific antibodies that do not compete with ligands binding retained their full cytotoxic activity in the presence of ligands, a valuable property to circumvent immunosuppressive effects induced by soluble ligands in the microenvironment.

Frontiers in Immunology

Triple negative breast cancers (TNBC) remain a major medical challenge due to poor prognosis and ... more Triple negative breast cancers (TNBC) remain a major medical challenge due to poor prognosis and limited treatment options. Mesothelin is a glycosyl-phosphatidyl inositol-linked membrane protein with restricted normal expression and high level expression in a large proportion of TNBC, thus qualifying as an attractive target. Its overexpression in breast tumors has been recently correlated with a decreased disease-free survival and an increase of distant metastases. The objective of the study was to investigate the relevance of a bispecific antibody-based immunotherapy approach through mesothelin targeting and CD16 engagement using a Fab-like bispecific format (MesobsFab). Using two TNBC cell lines with different level of surface mesothelin and epithelial/mesenchymal phenotypes, we showed that, in vitro, MesobsFab promotes the recruitment and penetration of NK cells into tumor spheroids, induces potent dose-dependent cell-mediated cytotoxicity of mesothelin-positive tumor cells, cytokine secretion, and decreases cell invasiveness. MesobsFab was able to induce cytotoxicity in resting human peripheral blood mononuclear cells (PBMC), mainly through its NK cells-mediated antibody dependent cell cytotoxicity (ADCC) activity. In vivo, the anti-tumor effect of MesobsFab depends upon a threshold of MSLN density on target cells. Collectively our data support mesothelin as a relevant therapeutic target for the subset of TNBC that overexpresses mesothelin characterized by a low overall and disease-free survival as well as the potential of MesobsFab as antibody-based immunotherapeutics.

Scientific Reports

Early detection of malignant tumours and, especially, micrometastases and disseminated tumour cel... more Early detection of malignant tumours and, especially, micrometastases and disseminated tumour cells is still a challenge. In order to implement highly sensitive diagnostic tools we demonstrate the use of nanoprobes engineered from nanobodies (single-domain antibodies, sdAbs) and fluorescent quantum dots (QDs) for single-and two-photon detection and imaging of human micrometastases and disseminated tumour cells in ex vivo biological samples of breast and pancreatic metastatic tumour mouse models expressing human epidermal growth factor receptor 2 (HER2) or carcinoembryonic antigen (CEA). By staining thin (5-10 µm) paraffin and thick (50 µm) agarose tissue sections, we detected HER2-and CEA-positive human tumour cells infiltrating the surrounding tissues or metastasizing to different organs, including the brain, testis, lung, liver, and lymph nodes. Compared to conventional fluorescently labelled antibodies the sdAb-HER2-QD and sdAb-CEA-QD nanoprobes are superior in detecting micrometastases in tissue sections by lower photobleaching and higher brightness of fluorescence signals ensuring much better discrimination of positive signals versus background. Very high two-photon absorption cross-sections of QDs and small size of the nanoprobes ensure efficient imaging of thick tissue sections unattainable with conventional fluorescent probes. The nanobody-QD probes will help to improve early cancer diagnosis and prognosis of progression by assessing metastasis. Cancer still remains a great challenge to public health and represents a giant economic burden to the society. In 2013, more than one and a quarter million people died from cancer in the European Union 1. To improve cancer prognosis and, hence, patients' survival, early detection of the disease is one of the main purposes in diagnostic approaches. In this regard, the rapidly progressing field of nanotechnology is considered a powerful tool in cancer diagnostic and therapeutic applications 2,3. The development of new nanoprobes which can detect cancer biomarkers with high specificity and sensitivity is appealing. The use of nanomaterials brings a number of advantages not only in diagnostics, but also in therapeutic concepts, such as improvement of water compatibility of hydrophobic drugs, their protection from degradation, with the result of a longer release, increase in drug bioavailability, tumour selectivity, and greater penetration depths for the treatment of deep seated tumours 4,5. Among the

Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2018

Mesothelin is a cell-surface glycoprotein restricted to mesothelial cells overexpressed in severa... more Mesothelin is a cell-surface glycoprotein restricted to mesothelial cells overexpressed in several types of cancer, including triple-negative breast cancer not responding to trastuzumab or hormone-based therapies. Mesothelin-targeting therapies are currently being developed. However, the identification of patients potentially eligible for such a therapeutic strategy remains challenging. The objective of this study was to perform the radiolabeling and preclinical evaluation of Tc-A1 and Tc-C6, two antimesothelin single-domain antibody (sdAb)-derived imaging agents. A1 and C6 were radiolabeled with Tc and evaluated in vitro on recombinant protein and cells, as well as in vivo in xenograft mouse models of the triple-negative breast cancer cell lines HCC70 (mesothelin-positive) and MDA-MB-231 (mesothelin-negative). Both Tc-A1 and Tc-C6 bound mesothelin with high affinity in vitro, with Tc-A1 affinity being 2.4-fold higher than that of Tc-C6 (dissociation constant, 43.9 ± 4.0 vs. 107 ± 1...

Nature communications, Dec 6, 2017

Antibodies have enormous therapeutic and biotechnology potential. G protein-coupled receptors (GP... more Antibodies have enormous therapeutic and biotechnology potential. G protein-coupled receptors (GPCRs), the main targets in drug development, are of major interest in antibody development programs. Metabotropic glutamate receptors are dimeric GPCRs that can control synaptic activity in a multitude of ways. Here we identify llama nanobodies that specifically recognize mGlu2 receptors, among the eight subtypes of mGluR subunits. Among these nanobodies, DN10 and 13 are positive allosteric modulators (PAM) on homodimeric mGlu2, while DN10 displays also a significant partial agonist activity. DN10 and DN13 have no effect on mGlu2-3 and mGlu2-4 heterodimers. These PAMs enhance the inhibitory action of the orthosteric mGlu2/mGlu3 agonist, DCG-IV, at mossy fiber terminals in the CA3 region of hippocampal slices. DN13 also impairs contextual fear memory when injected in the CA3 region of hippocampal region. These data highlight the potential of developing antibodies with allosteric actions on...

Proceedings of the National Academy of Sciences

The immunity protein to colicin A (Cai), which is constitutively expressed at a very low level in... more The immunity protein to colicin A (Cai), which is constitutively expressed at a very low level in Escherichia coli strains, has been studied in recombinant plasmid constructs allowing expression of various immunity fusion proteins under the control of inducible promoters. The 13amino acid NH2-terminal region of Cai was substituted by polypeptides from 13-galactosidase or from colicin A. Upon induction of the chimeric proteins, the rate of expression of the immunity protein could be correlated to the level of resistance to colicin A. The immunity protein has been "tagged" with an epitope from the colicin A protein for which a monoclonal antibody is available. Using this technique, we have directly demonstrated that the immunity protein is located in the cytoplasmic membrane. The results indicate that the NH2terminal region of Cai is directed toward the cytoplasm and is probably not required for Cai insertion into the membrane or for its function.

The Journal of Biological Chemistry, 1994

Bulletin Du Cancer, Dec 21, 2000

Journal of Molecular Biology, Aug 20, 1992

The structure of complexes of RecA with double-stranded and single-stranded DNA was studied by li... more The structure of complexes of RecA with double-stranded and single-stranded DNA was studied by linear dichroism spectroscopy, fluorescence quenching and fluorescence anisotropy measurements. One of the two tryptophan residues (Trp291) of RecA was replaced by genetic engineering for an ultraviolet light-transparent threonine. This modified RecA protein shows, within experimental errors, the same DNA-binding kinetics and stoichiometry as the wild-type protein and no significant variation with respect to in vivo repair function was observed between cells with the two protein forms. By comparing the dichroic and fluorescence properties of the wild-type versus the modified protein, when bound to DNA, information about orientation and environment of the Trp291 chromophore in the complex could be obtained. The indole chromophore of Trp291Z was found to be oriented with its pseudo-long axis tilted 61 degrees and the aromatic plane is tilted 27 degrees relative to the fibre axis. Trp291 shows low mobility within the protein and therefore the deduced orientation may be used as a "handle" on the protein at the construction of three-dimensional models of RecA-DNA complexes. Comparison with the orientation for this residue in the crystal structure of the RecA homopolymer fibre indicates no measurable reorientation of the C-terminal subdomain of RecA upon DNA binding. Whereas the accuracy of the orientation determination of tryptophan, in absolute terms, is rather poor, changes of its orientation can be detected with high precision. Thus, similar Trp291 orientations are obtained in the complexes with single-stranded and double-stranded DNA, indicating similar structures of the protein fibres. The fluorescence quenching results indicate that the protein region of Trp291 is not involved in the binding of DNA.

Mol Gen Genet, 1987

The genetic behaviour of short non-homologous regions has been studied during transformation of S... more The genetic behaviour of short non-homologous regions has been studied during transformation of Streptococcus pneumoniae. Amethopterin-resistant mutants belonging to the amiA locus were used for these investigations. Five mutants deleted for 1-5 bp were obtained by oligonucleotide-directed mutagenesis. Their efficiency of transformation was measured using recipient strains either able to excise and repair mismatched bases (Hex +) or Hex derivatives. Deletions or insertions of I and 2 bp are fully recognized by the Hex system, and are efficiently repaired whereas 3-bp deletions or insertions are only partially excised and repaired. The efficiency of repair is inversely related to the size of the non-homology. Markers with 5-bp deletions or insertions are poorly repaired and thus transform at very high frequency: similar results are obtained in reciprocal crosses. It is proposed that 1-or 2-bp deletions or insertions are included in the heteroduplex structure as transition mutations. The Hex system would detect only small deviations from the normal DNA structure.

Scientific reports, 2016

The detection of tumours in an early phase of tumour development in combination with the knowledg... more The detection of tumours in an early phase of tumour development in combination with the knowledge of expression of tumour markers such as epidermal growth factor receptor (EGFR) is an important prerequisite for clinical decisions. In this study we applied the anti-EGFR nanobody (99m)Tc-D10 for visualizing small tumour lesions with volumes below 100 mm(3) by targeting EGFR in orthotopic human mammary MDA-MB-468 and MDA-MB-231 and subcutaneous human epidermoid A431 carcinoma mouse models. Use of nanobody (99m)Tc-D10 of a size as small as 15.5 kDa enables detection of tumours by single photon emission computed tomography (SPECT) imaging already 45 min post intravenous administration with high tumour uptake (>3% ID/g) in small MDA-MB-468 and A431 tumours, with tumour volumes of 52.5 mm(3) ± 21.2 and 26.6 mm(3) ± 16.7, respectively. Fast blood clearance with a serum half-life of 4.9 min resulted in high in vivo contrast and ex vivo tumour to blood and tissue ratios. In contrast, no a...

Antibodies, 2015

As evidenced by the recent approvals of Removab (EU, Trion Pharma) in 2009 and of Blincyto (US, A... more As evidenced by the recent approvals of Removab (EU, Trion Pharma) in 2009 and of Blincyto (US, Amgen) in 2014, the high potential of bispecific antibodies in the field of immuno-oncology is eliciting a renewed interest from pharmaceutical companies. Supported by rapid advances in antibody engineering and the development of several technological platforms such as Triomab or bispecific T cell engagers (BiTEs), the "bispecifics" market has increased significantly over the past decade and may occupy a pivotal space in the future. Over 30 bispecific molecules are currently in different stages of clinical trials and more than 70 in preclinical phase. This review focuses on the clinical potential of bispecific antibodies as immune effector cell engagers in the onco-immunotherapy field. We summarize current strategies targeting various immune cells and their clinical interests. Furthermore, perspectives of bispecific antibodies in future clinical developments are addressed.

2015 International Conference on Biomedical Engineering and Computational Technologies (SIBIRCON), 2015

Ms Medecine Sciences, Dec 1, 2009

Les anticorps thérapeutiques sont enfin devenus une réalité. Le développement de l'ingénierie des... more Les anticorps thérapeutiques sont enfin devenus une réalité. Le développement de l'ingénierie des anticorps a permis l'obtention d'anticorps monoclonaux (Acm) chimériques, humanisés et même totalement humains beaucoup plus efficaces, conduisant à l'acceptation de plus d'une vingtaine d'anticorps thérapeutiques en clinique pour le traitement de maladies inflammatoires, auto-immunes, virales ou cancéreuses [1]. Cependant, les Acm présentent toujours d'importantes limitations, entre autres un haut poids moléculaire (150 kDa) limitant sérieusement leur pénétration dans les tumeurs solides [2], et des coûts de production très élevés (➜). Ainsi, sur neuf anticorps acceptés pour le traitement des tumeurs, seuls trois Anticorps thérapeutiques et immunociblage,

Journal of Molecular Biology, 1991