HP-1γ Controls High-Affinity Antibody Response to T-Dependent Antigens

Targeting Cbx3/HP1γ Induces LEF-1 and IL-21R to Promote Tumor-Infiltrating CD8 T-Cell Persistence

Immune checkpoint blockade (ICB) relieves CD8⁺ T-cell exhaustion in most mutated tumors, and TCF-1 is implicated in converting progenitor exhausted cells to functional effector cells. However, identifying mechanisms that can prevent functional senescence and potentiate CD8⁺ T-cell persistence for ICB non-responsive and resistant tumors remains elusive. We demonstrate that targeting Cbx3/HP1γ in CD8⁺ T cells augments transcription initiation and chromatin remodeling leading to increased transcriptional activity at Lef1 and Il21r. LEF-1 and IL-21R are necessary for Cbx3/HP1γ-deficient CD8⁺ effector T cells to persist and control ovarian cancer, melanoma, and neuroblastoma in preclinical models. The enhanced persistence of Cbx3/HP1γ-deficient CD8⁺ T cells facilitates remodeling of the tumor chemokine/receptor landscape ensuring their optimal invasion at the expense of CD4⁺ Tregs. Thus, CD8⁺ T cells heightened effector function consequent to Cbx3/HP1γ deficiency may be distinct from functional reactivation by ICB, implicating Cbx3/HP1γ as a viable cancer T-cell-based therapy target for ICB resistant, non-responsive solid tumors.

The State of Cellular Adoptive Immunotherapy for Neuroblastoma and Other Pediatric Solid Tumors

Research on adult cancer immunotherapy is proceeding at a rapid pace resulting in an impressive success rate exemplified by a few high profile cases. However, this momentum is not readily extended to pediatric immunotherapy, and it is not for lack of trying. Though reasons for the slower advance are not apparent, some issues can be raised. Pediatric cancer patients represent a distinct demographic group whose immune system is inherently different from that of mature adults. Treating pediatric patients with immunotherapy designed for adults may not yield objective clinical responses. Here, we will present an update on adoptive T-cell and natural killer-cell therapies for neuroblastoma and other childhood solid tumors. Additionally, we will delineate key differences between human fetal/neonatal and adult immune systems. We hope this will generate interests leading to the discussion of potential future directions for improving adoptive cancer immunotherapy for children.

Cbx3/HP1γ deficiency confers enhanced tumor-killing capacity on CD8+ T cells

Cbx3/HP1γ is a histone reader whose function in the immune system is not completely understood. Here, we demonstrate that in CD8⁺ T cells, Cbx3/HP1γ insufficiency leads to chromatin remodeling accompanied by enhanced Prf1, Gzmb and Ifng expression. In tumors obtained from Cbx3/HP1γ-insufficient mice or wild type mice treated with Cbx3/HP1γ-insufficient CD8⁺ T cells, there is an increase of CD8⁺ effector T cells expressing the stimulatory receptor Klrk1/NKG2D, a decrease in CD4⁺ CD25⁺ FOXP3⁺ regulatory T cells (Treg cells) as well as CD25⁺ CD4⁺ T cells expressing the inhibitory receptor CTLA4. Together these changes in the tumor immune environment may have mitigated tumor burden in Cbx3/HP1γ-insufficient mice or wild type mice treated with Cbx3/HP1γ-insufficient CD8⁺ T cells. These findings suggest that targeting Cbx3/HP1γ can represent a rational therapeutic approach to control growth of solid tumors.

Recombinant NDV expressing cytokines or fliC confers a quick immune response against NDV challenge and resistance to maternal antibody

Currently, there are two major bottleneck problems which seriously affect prevention of the Newcastle disease (ND): interference of maternal antibody on NDV vaccination and slow production of neutralization antibody. To overcome these problems, in present study, four rNDV vaccine strains expressing bio-adjuvants chIL2, chIL15, chGM-CSF or fliC gene were constructed and rescued using reverse genetics approach. The HI antibody titers of SPF birds immunized with rNDV reached to 5.5log2, 4.7log2, 6.5log2 and 5.8log2, respectively at the 8th day post immunization, while the antibody titers of the parental virus and control were 3.3log2 and 1log2, respectively. The immunized chickens were challenged by 10⁴ELD₅₀ dose of the virulent NDV BJ strains at the 7th day post immunization. The protection rate of the four rNDVs bio-adjuvant groups was 100%, while the protection rate of the parental group was 80%. We also examined the anti-maternal antibody activity of these adjuvant vaccines by detection HI titer after vaccination of chickens with high (8.4log2) or low (5log2) maternal antibody levels. In chicken flock with higher maternal antibody, parental strain could not resist the influence of the maternal antibody and induce any notable change of HI antibody kinetics. However, both rClon30-chGM-CSF and rClon30-flic were able to resist the influence of the maternal antibody and maintained the HI antibody above the protection level during the 14day's experiment. In chicken flock with lower maternal antibody, the parental rclone30 strain could not induce HI titer to the protection level until the 14th day, but both rClon30-GM-CSF and clone30-fliC raised the HI antibody to above the protection level at the 7th day post vaccination.