Comparative genomics and host resistance against infectious diseases.

The large size and complexity of the human genome have limited the identification and functional characterization of components of the innate immune system that play a critical role in front-line defense against invading microorganisms. However, advances in genome analysis (including the development of comprehensive sets of informative genetic markers, improved physical mapping methods, and novel techniques for transcript identification) have reduced the obstacles to discovery of novel host resistance genes. Study of the genomic organization and content of widely divergent vertebrate species has shown a remarkable degree of evolutionary conservation and enables meaningful cross-species comparison and analysis of newly discovered genes. Application of comparative genomics to host resistance will rapidly expand our understanding of human immune defense by facilitating the translation of knowledge acquired through the study of model organisms. We review the rationale and resources for comparative genomic analysis and describe three examples of host resistance genes successfully identified by this approach

CD19/CD22 targeting with co-transduced CAR T-cells to prevent antigen negative relapse after CAR T-cell therapy of B-ALL

CD19-negative relapse is a leading cause of treatment failure after Chimeric antigen receptor (CAR) T-cell therapy for ALL. We investigated a CAR T-cell product targeting CD19 and CD22 generated by lentiviral co-transduction with vectors encoding our previously-described fast-off rate CD19CAR (AUTO1) combined with a novel CD22CAR capable of effective signalling at low antigen density. Twelve patients with advanced B-ALL were treated (CARPALL study, NCT02443831), a third of whom had failed prior licensed CAR therapy. Toxicity was similar to that of AUTO1 alone, with no cases of severe cytokine release syndrome. Ten of 12 patients (83%) achieved a Measurable Residual Disease (MRD) negative complete remission at 2 months post infusion. Of 10 responding patients, 5 had emergence of MRD (2) or relapse (3) with CD19 and CD22 expressing disease associated with loss of CAR T-cell persistence. With a median follow-up of 8.7 months there were no cases of relapse due to antigen-negative escape. Overall survival was 75% (95%CI: 41-91%) at 6 and 12 months. Six and 12-month event free survival (EFS) were 75% (95%CI: 41-91%) and 60% (95%CI: 23-84%). These data suggest dual targeting with co-transduction may prevent antigen negative relapse after CAR T-cell therapy

Phase 1 clinical trial of CRISPR-engineered CAR19 universal T cells for treatment of children with refractory B cell leukemia

Copyright © 2022 The Authors, some rights reserved.Genome editing of allogeneic T cells can provide “off-the-shelf” alternatives to autologous chimeric antigen receptor (CAR) T cell therapies. Disruption of T cell receptor α chain (TRAC) to prevent graft-versus-host disease (GVHD) and removal of CD52 (cluster of differentiation 52) for a survival advantage in the presence of alemtuzumab have previously been investigated using transcription activator–like effector nuclease (TALEN)-mediated knockout. Here, we deployed next-generation CRISPR-Cas9 editing and linked CAR expression to multiplexed DNA editing of TRAC and CD52 through incorporation of self-duplicating CRISPR guide RNA expression cassettes within the 3’ long terminal repeat of a CAR19 lentiviral vector. Three cell banks of TT52CAR19 T cells were generated and cryopreserved. A phase 1, open-label, non-randomized clinical trial was conducted and treated six children with relapsed/refractory CD19-positive B cell acute lymphoblastic leukemia (B-ALL) (NCT04557436). Lymphodepletion included fludarabine, cyclophosphamide, and alemtuzumab and was followed by a single infusion of 0.8 × 106 to 2.0 × 106 CAR19 T cells per kilogram with no immediate toxicities. Four of six patients infused with TT52CAR19 T cells exhibited cell expansion, achieved flow cytometric remission, and then proceeded to receive allogeneic stem cell transplantation. Two patients required biological intervention for grade II cytokine release syndrome, one patient developed transient grade IV neurotoxicity, and one patient developed skin GVHD, which resolved after transplant conditioning. Other complications were within expectations, and primary safety objectives were met. This study provides a demonstration of the feasibility, safety, and therapeutic potential of CRISPR-engineered immunotherapy.11Nsciescopu