Project description:Checkpoint blockage has revolutionized cancer treatment. NKG2A is an inhibitory receptor expressed by cytotoxic lymphocytes, including NK cells. In contrast to other checkpoint inhibitory antibodies, anti-NKG2A antibodies have shown only limited success. Here, we designed a Cas9-based strategy to delete KLRC1 from human NK cells. Electroporation of KLRC1-targeting Cas9-RNP efficiently eliminated NKG2A expression from primary human NK cells. NKG2A-deficient NK cells showed normal proliferation, only minor transcriptional changes related to enhanced NK cell activation and maintained their phenotype and licensing status. Genetic deletion of NKG2A fully bypassed HLA-E inhibition and further enhanced NK cell activity against various tumor cell lines, thereby outperforming anti-NKG2A antibodies. In combination with antibody-coating of tumor cells to induce antibody-dependent cellular cytotoxicity, genetic deletion of NKG2A independently promoted cytotoxicity. Thus, Cas9-mediated targeting of NKG2A is an effective way to target this important inhibitory checkpoint. This technique is easily amenable to adoptive cell therapy in the clinical setting, where NKG2A deletion will promote anti-tumor responses and may help NK cells to better infiltrate and persist in an inhibitory tumor microenvironment.
Project description:A key mechanism of tumor resistance to immune cells is mediated by expression of peptide-loaded HLA-E in tumor cells, which suppresses natural killer (NK) cell activity via ligation of the NK inhibitory receptor CD94/NKG2A. To bypass HLA-E inhibition, we developed a way to generate highly functional NK cells lacking NKG2A. Constructs containing a single-chain variable fragment derived from an anti-NKG2A antibody were linked to endoplasmic reticulum-retention domains. After retroviral transduction in human peripheral blood NK cells, these NKG2A Protein Expression Blockers (PEBLs) abrogated NKG2A expression. The resulting NKG2Anull NK cells had higher cytotoxicity against HLA-E-expressing tumor cells.
Project description:We studied the heterogeneity among human KIR/NKG2A+CD8+ T cells. First, we found that KIRs and NKG2A are expressed on human CD8+ T cells in a mutually exclusive manner. Therefore, we compared KIR+CD8+ and NKG2A+CD8+ T cells in regards to TCR overlap and transcriptomic profiles and demonstrated that KIR+CD8+ and NKG2A+CD8+ T cells are distinct innate-like populations.
Project description:We report abnormal pregnancy outcomes in mice lacking NKG2A, including altered placental transcription. In humans, we find HLAB-21T snp to be associated with an increased risk of pre-eclampsia.
Project description:The ability to modulate immune-inhibitory pathways using checkpoint blockade antibodies such as PD-1, PD-L1, and CTLA-4 represents a significant breakthrough in cancer therapy in recent years. This has driven interest in identifying small-molecule-immunotherapy combinations to increase the proportion of responses. Murine syngeneic models, which have a functional immune system, represent an essential tool for pre-clinical evaluation of new immunotherapies. However, immune response varies widely between models and the translational relevance of each model is not fully understood, making selection of an appropriate pre-clinical model for drug target validation challenging. Utilizing RNAseq transcriptomic profiling, we have characterised the changes in gene regulatory pathways and immune populations in CT26 mice after treatment with the combination of anti-PD-L1 and anti-CTLA-4 antibodies. At day 7 post tumor implant, the pathways analysis of differentially expressed genes indicated an enrichment for migration of leukocytes in response to inflammation and communication between innate and adaptive immune cells. Similarly, analysis of upstream regulators suggested that lipopolysaccharide, IL-1B, TNF, IFNG, and NFKB1A pathways associated with inflammation were activated. At day 14, pathways related T-helper cell signalling pathways were upregulated. In addition, upstream regulators of the lipopolysaccharide and IFNG pathway, as well STAT1 and IL21 pathway were enriched, indicative of innate and adaptive immune response to inflammation.
Project description:CD4 T cells can differentiate into a hetergenous population of effector T cells. A population of cytotoxic CD4 T cells can be generated against influenza challenge, however identifying these cells have been challenging. The expression of NKG2A/C/E on CD4 T cells identifies CD4 T cells with cytotoxic potential thus allowing further characterization of this subset of CD4 effector cells. Microarray analysis comparing cytotoxic CD4 T cells versus non-cytotoxic CD4 T cells reveals unique differences in localization between these populations in the lung after influenza A challenge.
Project description:CD19-targeting chimeric antigen receptor (CAR) T cell have become an important therapeutic option for patients with relapsed and refractory B cell malignancies. However, according to the recent clinical data, a significant portion of patients still do not benefit from the therapy, due various resistance mechanisms including the high expression of multiple inhibitory immune checkpoint receptors on activated CAR-T cells. Studies of checkpoint blockade immunotherapy using monoclonal antibodies have shown that simultaneously targeting inhibitory receptors that are functionally non-redundant can synergistically enhance anti-tumor responses. Here we report a lentiviral two-in-one CAR T approach in which two checkpoint receptors can be downregulated simultaneously by a dual short-hairpin RNA (shRNA) cassette integrated into a CAR vector. Using this system, we evaluated CD19-targeting CAR T cells in the context of four different checkpoint combinations, PD-1/TIM-3, PD-1/LAG-3, PD-1/CTLA-4, and PD-1/TIGIT, and found that the CAR T with PD-1/TIGIT downregulation uniquely exhibited synergistic anti-tumor effect in mouse xenograft models compared to the single PD-1 downregulation and maintained cytolytic and proliferative capacity upon repeated antigen exposure. Importantly, functional and phenotypic analysis of CAR T cells as well as analysis of transcriptomic profiles suggests that downregulation of PD-1 enhances short-term effector function while downregulation of TIGIT is primarily responsible for maintaining a less-differentiated/exhausted state, providing a potential mechanism of the synergy. The PD-1/TIGIT downregulated CAR T cells generated from DLBCL patient-derived T cells following clinically applicable manufacturing process also showed a robust anti-tumor activity and significantly improved persistence in vivo compared to conventional CD19-targeting CAR T cells. Overall, our results demonstrate that the cell-intrinsic PD-1/TIGIT dual downregulation strategy may provide an effective way to overcome the immune checkpoint-mediated resistance in CAR T therapy.
Project description:Immune checkpoint blockade (ICB) has shown remarkable efficacy, but in only a minority of cancer patients, suggesting the need to develop additional treatment strategies.We integrated transcriptional profiles of treatment-naïve human tumors and functional CRISPR screens to identify glycometabolism genes with immunomodulatory effects. We identified MAN2A1, encoding an enzyme in N-glycan maturation, as a key immunomodulatory gene. Analyses of public immune checkpoint blockade trial data also suggested a synergy between MAN2A1 inhibition and anti-PD-L1 treatment. Loss of Man2a1 in cancer cells increased their sensitivity to T cell-mediated killing. Man2a1 knockout enhanced response to anti-PD-L1 treatment and facilitated higher cytotoxic T cell infiltration in tumors under anti-PD-L1 treatment. Furthermore, a pharmacological inhibitor of MAN2A1, swainsonine, synergized with anti-PD-L1 in syngeneic melanoma tumor model, whereas each treatment alone had little effect.