Characterisation of an engineered trastuzumab IgE antibody and effector cell mechanisms targeting HER2/neu-positive tumour cells

Trastuzumab (Herceptin(®)), a humanized IgG1 antibody raised against the human epidermal growth factor receptor 2 (HER2/neu), is the main antibody in clinical use against breast cancer. Pre-clinical evidence and clinical studies indicate that trastuzumab employs several anti-tumour mechanisms that most likely contribute to enhanced survival of patients with HER2/neu-positive breast carcinomas. New strategies are aimed at improving antibody-based therapeutics like trastuzumab, e.g. by enhancing antibody-mediated effector function mechanisms. Based on our previous findings that a chimaeric ovarian tumour antigen-specific IgE antibody showed greater efficacy in tumour cell killing, compared to the corresponding IgG1 antibody, we have produced an IgE homologue of trastuzumab. Trastuzumab IgE was engineered with the same light- and heavy-chain variable-regions as trastuzumab, but with an epsilon in place of the gamma-1 heavy-chain constant region. We describe the physical characterisation and ligand binding properties of the trastuzumab IgE and elucidate its potential anti-tumour activities in functional assays. Both trastuzumab and trastuzumab IgE can activate monocytic cells to kill tumour cells, but they operate by different mechanisms: trastuzumab functions in antibody-dependent cell-mediated phagocytosis (ADCP), whereas trastuzumab IgE functions in antibody-dependent cell-mediated cytotoxicity (ADCC). Trastuzumab IgE, incubated with mast cells and HER2/neu-expressing tumour cells, triggers mast cell degranulation, recruiting against cancer cells a potent immune response, characteristic of allergic reactions. Finally, in viability assays both antibodies mediate comparable levels of tumour cell growth arrest. These functional characteristics of trastuzumab IgE, some distinct from those of trastuzumab, indicate its potential to complement or improve upon the existing clinical benefits of trastuzumab

Search for strongly interacting massive particles generating trackless jets in proton–proton collisions at s=13 TeV\sqrt{s} = 13\,\text {TeV}

International audienceA search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton–proton collision data corresponding to an integrated luminosity of 16.1$\,\text {fb}^{-1}$, collected with the CMS detector in 2016. No significant excess of events is observed above the expected background. For the simplified dark matter model under consideration, SIMPs with masses up to 100$\,\text {GeV}$ are excluded and further sensitivity is explored towards higher masses