HIV infection significantly affects the frequencies and functions of immunoregulatory CD3+CD4-CD8- double-negative (DN) T-cells, while the effect of early antiretroviral therapy (ART) initiation on these cells remains understudied. DN T-cell subsets were analyzed prospectively in 10 HIV+ individuals during acute infection and following early ART initiation compared to 20 HIV-uninfected controls. In this study, 21 Rhesus macaques (RMs) were SIV-infected, of which 13 were assessed during acute infection and 8 following ART initiation four days post-infection. DN T-cells and FoxP3+ DN Treg frequencies increased during acute HIV infection, which was not restored by ART. The expression of activation (HLA-DR/CD38), immune checkpoints (PD-1/CTLA-4), and senescence (CD28-CD57+) markers by DN T-cells and DN Tregs increased during acute infection and was not normalized by ART. In SIV-infected RMs, DN T-cells remained unchanged despite infection or ART, whereas DN Treg frequencies increased during acute SIV infection and were not restored by ART. Finally, frequencies of CD39+ DN Tregs increased during acute HIV and SIV infections and remained elevated despite ART. Altogether, acute HIV/SIV infections significantly changed DN T-cell and DN Treg frequencies and altered their immune phenotype, while these changes were not fully normalized by early ART, suggesting persistent HIV/SIV-induced immune dysregulation despite early ART initiation.

Memory T cells demonstrate superior in vivo persistence and antitumor efficacy. However, methods for manufacturing less differentiated T cells are not yet well-established. Here, we show that producing chimeric antigen receptor (CAR)-T cells using berbamine (BBM), a natural compound found in the Chinese herbal medicine Berberis amurensis, enhances the antitumor efficacy of CAR-T cells. BBM is identified through cell-based screening of chemical compounds using induced pluripotent stem cell-derived T cells, leading to improved viability with a memory T cell phenotype. Transcriptomics and metabolomics using stem cell memory T cells reveal that BBM broadly enhances lipid metabolism. Furthermore, the addition of BBM downregulates the phosphorylation of p38 mitogen-activated protein kinase and enhanced mitochondrial respiration. CD19-CAR-T cells cultured with BBM also extend the survival of leukaemia mouse models due to their superior in vivo persistence. This technology offers a straightforward approach to enhancing the antitumor efficacy of CAR-T cells.
© 2024. The Author(s).

The transplantation of gene-modified autologous hematopoietic stem and progenitor cells (HSPCs) offers a promising therapeutic approach for hematological and immunological disorders. However, this strategy is often limited by the toxicities associated with traditional conditioning regimens. Antibody-based conditioning strategies targeting cKIT and CD45 antigens have shown potential in mitigating these toxicities, but their long-term safety and efficacy in clinical settings require further validation. In this study, we investigate the thrombopoietin (TPO) receptor, cMPL, as a novel target for conditioning protocols. We demonstrate that high surface expression of cMPL is a hallmark feature of long-term repopulating hematopoietic stem cells (LT-HSCs) within the adult human CD34+ HSPC subset. Targeting the cMPL receptor facilitates the separation of human LT-HSCs from mature progenitors, a delineation not achievable with cKIT. Leveraging this finding, we developed a cMPL-targeting immunotoxin, demonstrating its ability to selectively deplete host cMPL high LT-HSCs with a favorable safety profile and rapid clearance within 24 hours post-infusion in rhesus macaques. These findings present significant potential to advance our understanding of human hematopoiesis and enhance the therapeutic outcomes of ex vivo autologous HSPC gene therapies. Abstract Figure Graphical abstract

Substitution of lysine 27 to methionine in histone H3 (H3K27M) defines an aggressive subtype of diffuse glioma. Previous studies have shown that a H3K27M-specific long peptide vaccine (H3K27M-vac) induces mutation-specific immune responses that control H3K27M+ tumors in major histocompatibility complex-humanized mice. Here we describe a first-in-human treatment with H3K27M-vac of eight adult patients with progressive H3K27M+ diffuse midline glioma on a compassionate use basis. Five patients received H3K27M-vac combined with anti-PD-1 treatment based on physician's discretion. Repeat vaccinations with H3K27M-vac were safe and induced CD4+ T cell-dominated, mutation-specific immune responses in five of eight patients across multiple human leukocyte antigen types. Median progression-free survival after vaccination was 6.2 months and median overall survival was 12.8 months. One patient with a strong mutation-specific T cell response after H3K27M-vac showed pseudoprogression followed by sustained complete remission for >31 months. Our data demonstrate safety and immunogenicity of H3K27M-vac in patients with progressive H3K27M+ diffuse midline glioma.
© 2023. The Author(s).

Hematopoietic stem cell gene therapy has been successfully used for a number of genetic diseases and is also being explored for HIV. However, toxicity of the conditioning regimens has been a major concern. Here we compared current conditioning approaches in a clinically relevant nonhuman primate model. We first customized various aspects of the therapeutic approach, including mobilization and cell collection protocols, conditioning regimens that support engraftment with minimal collateral damage, and cell manufacturing and infusing schema that reflect and build on current clinical approaches. Through a series of iterative in vivo experiments in two macaque species, we show that busulfan conditioning significantly spares lymphocytes and maintains a superior immune response to mucosal challenge with simian/human immunodeficiency virus, compared to total body irradiation and melphalan regimens. Comparative mobilization experiments demonstrate higher cell yield relative to our historical standard, primed bone marrow and engraftment of CRISPR-edited hematopoietic stem and progenitor cells (HSPCs) after busulfan conditioning. Our findings establish a detailed workflow for preclinical HSPC gene therapy studies in the nonhuman primate model, which in turn will support testing of novel conditioning regimens and more advanced HSPC gene editing techniques tailored to any disease of interest.
© 2023 The Authors.