HIV remains a major public health issue in spite of antiretroviral therapy (ART). An innovative vaccine that can induce long-lasting and effective immunity is required to curb the persistently high numbers of new infections worldwide.
A novel DNA vaccine was generated using a Simian-Human Immunodeficiency Virus (SHIV) backbone with a Zambian T/F clade C envelope and under the control of the caprine arthritis encephalitis virus long terminal repeats (LTRs) for constitutive expression. Due to the deleted integrase, this DNA vaccine "CSH-DIN-T/F Z331" performs only a single replication cycle. To increase immunogenicity, the co-expression of apoptotic genes (BAX, BAK, or caspase 8) incorporated at the end of Pol was tested to promote the release of apoptotic bodies taken up by dendritic cells leading to cross-presentation of antigen. The three vaccines (CSH-DIN-T/F Z331-BAX, CSH-DIN-T/F Z331-BAK, and CSH-DIN-T/F Z331-Cas8) were tested in vitro for expression and in vivo in BALB/cJ mice for immunogenicity.
Transduced HEK293 cells co-cultured with CEMx174 confirmed the single replication cycle of the DNA vaccine and the induction of apoptosis by CSH-DIN-T/F Z331-Cas8 based on Annexin V expression. BALB/cJ mice were immunized with a combined intramuscular + intradermal/electroporation approach. Intracellular cytokine staining (ICS) from splenocytes collected 12 weeks post-prime/6 weeks post-boost demonstrated a clear superiority of caspase 8 expressing construct over the others, with higher proportions of IFN-γ-, IL-2-, and IL-21-producing CD8 T cells specific to Env, Gag, and Nef. The kinetics of immune response after various immunization schedules were also investigated.
This novel single-cycle DNA vaccine with apoptotic genes demonstrated an enhanced immunogenicity primarily for antigen-specific CD8+ T-cell responses.
Copyright © 2025 Bose, Rogers, Shirreff, Chebloune and Villinger.

The contribution of circulating verses tissue resident memory T cells (TRMs) to clinical neuropathology is an enduring question due to a lack of mechanistic insights. The prevailing view is TRMs are protective against pathogens in the brain. However, the extent to which antigen-specific TRMs induce neuropathology upon reactivation is understudied. Using the described phenotype of TRMs, we found that brains of naïve mice harbor populations of CD69+ CD103- T cells. Notably, numbers of CD69+ CD103- TRMs rapidly increase following neurological insults of various origins. This TRM expansion precedes infiltration of virus antigen-specific CD8 T cells and is due to proliferation of T cells within the brain. We next evaluated the capacity of antigen-specific TRMs in the brain to induce significant neuroinflammation post virus clearance, including infiltration of inflammatory myeloid cells, activation of T cells in the brain, microglial activation, and significant blood brain barrier disruption. These neuroinflammatory events were induced by TRMs, as depletion of peripheral T cells or blocking T cell trafficking using FTY720 did not change the neuroinflammatory course. Depletion of all CD8 T cells, however, completely abrogated the neuroinflammatory response. Reactivation of antigen-specific TRMs in the brain also induced profound lymphopenia within the blood compartment. We have therefore determined that antigen-specific TRMs can induce significant neuroinflammation, neuropathology, and peripheral immunosuppression. The use of cognate antigen to reactivate CD8 TRMs enables us to isolate the neuropathologic effects induced by this cell type independently of other branches of immunological memory, differentiating this work from studies employing whole pathogen re-challenge. This study also demonstrates the capacity for CD8 TRMs to contribute to pathology associated with neurodegenerative disorders and long-term complications associated with viral infections. Understanding functions of brain TRMs is crucial in investigating their role in neurodegenerative disorders including MS, CNS cancers, and long-term complications associated with viral infections including COVID-19.
Copyright © 2023 Elsevier Inc. All rights reserved.

Glioblastoma (GBM) is the most common malignant brain tumor in adults, responsible for approximately 225,000 deaths per year. Despite preclinical successes, most interventions have failed to extend patient survival by more than a few months. Treatment with anti-programmed cell death protein 1 (anti-PD-1) immune checkpoint blockade (ICB) monotherapy has been beneficial for malignant tumors such as melanoma and lung cancers but has yet to be effectively employed in GBM. This study aimed to determine whether supplementing anti-PD-1 ICB with engineered extended half-life IL2, a potent lymphoproliferative cytokine, could improve outcomes. This combination therapy, subsequently referred to as enhanced checkpoint blockade (ECB), delivered intraperitoneally, reliably cures approximately 50% of C57BL/6 mice bearing orthotopic GL261 gliomas and extends median survival of the treated cohort. In the CT2A model, characterized as being resistant to CBI, ECB caused a decrease in CT2A tumor volume in half of measured animals similar to what was observed in GL261-bearing mice, promoting a trending survival increase. ECB generates robust immunologic responses, features of which include secondary lymphoid organ enlargement and increased activation status of both CD4 and CD8 T cells. This immunity is durable, with long-term ECB survivors able to resist GL261 rechallenge. Through employment of depletion strategies, ECB's efficacy was shown to be independent of host MHC class I-restricted antigen presentation but reliant on CD4 T cells. These results demonstrate ECB is efficacious against the GL261 glioma model through an MHC class I-independent mechanism and supporting further investigation into IL2-supplemented ICB therapies for tumors of the central nervous system.
©2023 American Association for Cancer Research.

Peripheral T-cell lymphoma (PTCL) represents a rare group of heterogeneous diseases in urgent need of effective treatments. A scarcity of disease-relevant preclinical models hinders research advances. Here, we isolated a novel mouse (m)PTCL by serially transplanting a lymphoma from a germinal center B-cell hyperplasia model (Cγ1-Cre Blimp1fl/fl ) through immune-competent mice. Lymphoma cells were identified as clonal TCRβ+ T-helper cells expressing T-follicular helper markers. We also observed coincident B-cell activation and development of a de novo B-cell lymphoma in the model, reminiscent of B-cell activation/lymphomagenesis found in human PTCL. Molecular profiling linked the mPTCL to the high-risk "GATA3" subtype of PTCL, showing GATA3 and Th2 gene expression, PI3K/mTOR pathway enrichment, hyperactivated MYC, and genome instability. Exome sequencing identified a human-relevant oncogenic β-catenin mutation possibly involved in T-cell lymphomagenesis. Prolonged treatment responses were achieved in vivo by targeting ATR in the DNA damage response (DDR), a result corroborated in PTCL cell lines. This work provides mechanistic insight into the molecular and immunological drivers of T-cell lymphomagenesis and proposes DDR inhibition as an effective and readily translatable therapy in PTCL.
© 2022 The Authors. Published under the terms of the CC BY 4.0 license.

The contribution of circulating verses tissue resident memory T cells (TRM) to clinical neuropathology is an enduring question due to a lack of mechanistic insights. The prevailing view is TRM cells are protective against pathogens in the brain. However, the extent antigen-specific TRM cells can induce neuropathology upon reactivation has not been determined. Using the described phenotype of TRMs, we found that brains of naïve mice harbor populations of CD69 + CD103 − T cells. Notably, numbers of CD69 + CD103 − TRM cells rapidly increase following neurological insults of physical, cancerous, or viral origins. This TRM expansion precedes infiltration of virus specific CD8 T cells and is due to proliferation of T cells within the brain. In contrast, the CD69 + CD103 + TRMs in the brain are generated after the initial expansion of CD69 + CD103 − cells following injury and are antigen-specific. We next evaluated the capacity of antigen-specific TRMs in the brain to induce significant neuroinflammation post virus clearance, including infiltration of inflammatory monocytes, activation of T cells in the brain, and significant blood brain barrier disruption. These neuroinflammatory events were induced by TRMs, as depletion of peripheral T cells or blocking T cell trafficking using FTY720 did not change the neuroinflammatory course. Reactivation of antigen-specific TRMs in the brain also induced profound lymphopenia within the blood compartment. We have therefore determined that antigen-specific TRMs can induce significant neuroinflammation, neuropathology, and peripheral immune suppression. Importantly, understanding functions of brain TRMs is crucial in investigating their role in neurodegenerative disorders, CNS cancers, and long-term complications associated with viral infections including COVID-19. h4>Graphical Abstract/h4> Healthy brain harbors populations of resident memory T cells (TRM). These TRM cells rapidly proliferate in response to CNS insults of various origins. Following clearance of the insult, populations of TRM cells in the brain decline, but an antigen-specific TRM subset remains within the brain. Antigen-specific reactivation of brain TRMs mediates neuroinflammatory sequalae involving activation and blasting of resident T cells, infiltration of inflammatory monocytes and blood brain barrier disruption. Severe neuroinflammation within the brain following antigen-specific TRM reactivation is concurrent with profound lymphopenia within the blood compartment.