Improving the efficiency and effectiveness of an industrial SARS-CoV-2 diagnostic facility.

On 11th March 2020, the UK government announced plans for the scaling of COVID-19 testing, and on 27th March 2020 it was announced that a new alliance of private sector and academic collaborative laboratories were being created to generate the testing capacity required. The Cambridge COVID-19 Testing Centre (CCTC) was established during April 2020 through collaboration between AstraZeneca, GlaxoSmithKline, and the University of Cambridge, with Charles River Laboratories joining the collaboration at the end of July 2020. The CCTC lab operation focussed on the optimised use of automation, introduction of novel technologies and process modelling to enable a testing capacity of 22,000 tests per day. Here we describe the optimisation of the laboratory process through the continued exploitation of internal performance metrics, while introducing new technologies including the Heat Inactivation of clinical samples upon receipt into the laboratory and a Direct to PCR protocol that removed the requirement for the RNA extraction step. We anticipate that these methods will have value in driving continued efficiency and effectiveness within all large scale viral diagnostic testing laboratories

Optimisation des stratégies pour l'évolution dirigée des protéines

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

<i>In vitro</i>Evolution of Antibody Affinity via Insertional Mutagenesis Scanning of an Entire Antibody Variable Region

AbstractWe report the first systematic combinatorial exploration of affinity enhancement of antibodies by insertions and deletions (InDels). Transposon-based introduction of InDels via the method TRIAD was used to generate large libraries with random in-frame InDels across the entire scFv gene that were further recombined and screened by ribosome display. Knowledge of potential insertion points from TRIAD libraries formed the basis of exploration of length and sequence diversity of novel insertions by insertional-scanning mutagenesis (ISM). An overall 256-fold affinity improvement of an anti-IL-13 antibody BAK1 as a result of InDel mutagenesis and combination with known point mutations validates this approach and suggests that the results of this InDel approach and conventional exploration of point mutations can synergize to generate antibodies with higher affinity.SignificanceInsertion/deletion (InDel) mutations play key roles in genome and protein evolution. Despite their prominence in evolutionary history, the potential of InDels for changing function in protein engineering by directed evolution remains unexplored. Instead point mutagenesis is widely used. Here we create antibody libraries containing InDels and demonstrate that affinity maturation can be achieved in this way, establishing an alternative to the point mutation strategies employed in all previous in vitro selections. These InDels mirror the observation of considerable length variation in loops of natural antibodies originating from the same germline genes and be combined with point mutations, making both natural sources of functional innovation available for artificial evolution in the test tube.</jats:sec

In vitro evolution of antibody affinity via insertional scanning mutagenesis of an entire antibody variable region

Significance Insertion/deletion (InDel) mutations play key roles in genome and protein evolution. Despite their prominence in evolutionary history, the potential of InDels for changing function in protein engineering by directed evolution remains unexplored. Instead point mutagenesis is widely used. Here we create antibody libraries containing InDels and demonstrate that affinity maturation can be achieved in this way, establishing an alternative to the point mutation strategies employed in all previous in vitro selections. These InDels mirror the observation of considerable length variation in loops of natural antibodies originating from the same germline genes and be combined with point mutations, making both natural sources of functional innovation available for artificial evolution in the test tube.</jats:p

Abstract LB-158: MEDI4736: Delivering effective blockade of immunosupression to enhance tumour rejection: Monoclonal antibody discovery and preclinical development

Abstract Cancerous cells emerge within the body following accumulation of deleterious genetic mutations. These mutations alter the phenotype of a cancer cell marking it as distinct from the surrounding host; an immunological state termed “altered self”. These cells, like other non-self entities such as viruses and bacteria, are recognised by the immune system and marked for destruction, a process known as “immune surveillance”. B7-H1 expression by tumour cells is believed to aid tumours in evading detection and elimination by the immune system. B7-H1 functions in this respect via several alternative mechanisms including driving exhaustion and anergy of tumour infiltrating T lymphocytes, stimulating secretion of immune repressive cytokines into the tumour micro-environment, stimulating repressive regulatory T cell function and protecting B7-H1 expressing tumour cells from lysis by tumour cell specific cytotoxic T cells. Using hybridoma technology and high throughput screening MedImmune has identified a series of fully human antibodies specific for human B7-H1. Further characterisation of these antibodies led to the identification of a single high affinity antibody, MEDI 4736, with the ability to relieve B7-H1 mediated suppression of T cell activation in vitro and to enhance sub-optimal T cell activation in a mixed lymphocyte reaction. In vitro testing shows that MEDI 4736 does not trigger non-specific cytokine release in whole blood, and is only able to activate T cells in the context of an active T cell receptor signal. A surrogate anti-mouse B7-H1 antibody shows significant anti-tumour activity in a syngeneic model when dosed in combination with chemotherapy. Similarly MEDI 4736 is able to inhibit tumour growth in a novel in vivo xenograft model, via a mechanism that is dependent on the presence of tumour specific human T cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-158. doi:10.1158/1538-7445.AM2011-LB-158</jats:p

Rate of Asparagine Deamidation in a Monoclonal Antibody Correlating with Hydrogen Exchange Rate at Adjacent Downstream Residues

Antibodies are an important class of drugs, comprising more than half of all new FDA approvals. Therapeutic antibodies must be chemically stable both in storage and <i>in vivo</i>, following administration to patients. Deamidation is a major degradation pathway for all natural and therapeutic proteins circulating in blood. Here, the linkage between deamidation propensity and structural dynamics is investigated by examining two antibodies with differing specificities. While both antibodies share a canonical asparagine-glycine (NG) motif in a structural loop, this is prone to deamidation in one of the antibodies but not the other. We found that the hydrogen-exchange rate at the adjacent two amides, often the autocatalytic nucleophiles in deamidation, correlated with the rate of degradation. This previously unreported observation was confirmed upon mutation to stabilize the deamidation lability via a generally applicable orthogonal engineering strategy presented here. We anticipate that the structural insight into chemical degradation in full-length monoclonal antibodies and the high-resolution hydrogen-exchange methodology used will have broad application across biochemical study and drug discovery and development

Identification and Characterization of MEDI4736, an Antagonistic Anti–PD-L1 Monoclonal Antibody

Abstract Programmed cell-death 1 ligand 1 (PD-L1) is a member of the B7/CD28 family of proteins that control T-cell activation. Many tumors can upregulate expression of PD-L1, inhibiting antitumor T-cell responses and avoiding immune surveillance and elimination. We have identified and characterized MEDI4736, a human IgG1 monoclonal antibody that binds with high affinity and specificity to PD-L1 and is uniquely engineered to prevent antibody-dependent cell-mediated cytotoxicity. In vitro assays demonstrate that MEDI4736 is a potent antagonist of PD-L1 function, blocking interaction with PD-1 and CD80 to overcome inhibition of primary human T-cell activation. In vivo MEDI4736 significantly inhibits the growth of human tumors in a novel xenograft model containing coimplanted human T cells. This activity is entirely dependent on the presence of transplanted T cells, supporting the immunological mechanism of action for MEDI4736. To further determine the utility of PD-L1 blockade, an anti-mouse PD-L1 antibody was investigated in immunocompetent mice. Here, anti-mouse PD-L1 significantly improved survival of mice implanted with CT26 colorectal cancer cells. The antitumor activity of anti–PD-L1 was enhanced by combination with oxaliplatin, which resulted in increased release of HMGB1 within CT26 tumors. Taken together, our results demonstrate that inhibition of PD-L1 function can have potent antitumor activity when used as monotherapy or in combination in preclinical models, and suggest it may be a promising therapeutic approach for the treatment of cancer. MEDI4736 is currently in several clinical trials both alone and in combination with other agents, including anti–CTLA-4, anti–PD-1, and inhibitors of IDO, MEK, BRAF, and EGFR. Cancer Immunol Res; 3(9); 1052–62. ©2015 AACR.</jats:p