CD115- monocytic myeloid-derived suppressor cells are precursors of OLFM4high polymorphonuclear myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) consist of monocytic (M-) MDSCs and polymorphonuclear (PMN-) MDSCs that contribute to an immunosuppressive environment in tumor-bearing hosts. However, research on the phenotypic and functional heterogeneity of MDSCs in tumor-bearing hosts and across different disease stage is limited. Here we subdivide M-MDSCs based on CD115 expression and report that CD115^- M-MDSCs are functionally distinct from CD115⁺ M-MDSCs. CD115^- M-MDSCs increased in bone marrow and blood as tumors progressed. Transcriptome analysis revealed that CD115^- M-MDSCs expressed higher levels of neutrophil-related genes. Moreover, isolated CD115^- M-MDSCs had higher potential to be differentiated into PMN-MDSCs compared with CD115⁺ M-MDSCs. Of note, CD115^- M-MDSCs were able to differentiate into both olfactomedin 4 (OLFM4)^hi and OLFM4^lo PMN-MDSCs, whereas CD115⁺ M-MDSCs differentiated into a smaller proportion of OLFM4^lo PMN-MDSCs. In vivo, M-MDSC to PMN-MDSC differentiation occurred most frequently in bone marrow while M-MDSCs preferentially differentiated into tumor-associated macrophages in the tumor mass. Our study reveals the presence of previously unrecognized subtypes of CD115^- M-MDSCs in tumor-bearing hosts and demonstrates their cellular plasticity during tumorigenesis.

Dendritic cells pulsed with penetratin-OLFM4 inhibit the growth and metastasis of melanoma in mice

Cancer stem cells (CSCs) can self-renew and differentiate, contributing to tumor heterogeneity, metastasis, and recurrence. Their resistance to therapies, including immunotherapy, underscores the importance of targeting them for complete remission and relapse prevention. Olfactomedin 4 (OLFM4), a marker associated with various cancers such as colorectal cancer, is expressed on CSCs promoting immune evasion and tumorigenesis. However, its potential as a target for CSC-specific immunotherapy remains underexplored. The primary aim of this study is to evaluate the effectiveness of targeting OLFM4 with dendritic cell (DC)-based vaccines in inhibiting tumor growth and metastasis. To improve antigen delivery and immune response, OLFM4 was conjugated with a protein-transduction domain (PTD) from the antennapedia of Drosophila called penetratin, creating a fusion protein (P-OLFM4). The efficacy of DCs pulsed with P-OLFM4 (DCs [P-OLFM4]) was compared to DCs pulsed with OLFM4 (DCs [OLFM4]) and PBS (DCs [PBS]). DCs [P-OLFM4] inhibited tumor growth by 91.2 % and significantly reduced lung metastasis of OLFM4+ melanoma cells by 97 %, compared to the DCs [PBS]. DCs [OLFM4] also demonstrated a reduction in lung metastasis by 59.7 % compared to DCs [PBS]. Immunization with DCs [P-OLFM4] enhanced OLFM4-specific T-cell proliferation, interferon-γ production, and cytotoxic T cell activity in mice. The results indicate that OLFM4 is a viable target for CSC-focused immunotherapy. DC [P-OLFM4] vaccines can elicit robust immune responses, significantly inhibiting tumor growth and metastasis. This strategy holds promise for developing more effective cancer treatments that specifically target CSCs, potentially leading to better patient outcomes by reducing the likelihood of tumor relapse and metastasis.

HIFU-CCL19/21 Axis Enhances Dendritic Cell Vaccine Efficacy in the Tumor Microenvironment

BACKGROUND/OBJECTIVES

Effectively targeting treatment-resistant tumor cells, particularly cancer stem cells (CSCs) involved in tumor recurrence, remains a major challenge in immunotherapy. This study examines the potential of combining mechanical high-intensity focused ultrasound (M-HIFU) with dendritic cell (DC) vaccines to enhance immune responses against OLFM4-expressing tumors, a CSC marker linked to immune evasion and tumor growth.

METHODS

M-HIFU was applied to induce immunogenic cell death by mechanically disrupting tumor cells, releasing tumor-associated antigens and creating an immunostimulatory environment. DC vaccines loaded with OLFM4 were then administered to boost the immune response within this primed environment.

RESULTS

The combination of M-HIFU and DC vaccine significantly inhibited tumor growth and metastasis, with enhanced T-cell activation and increased recruitment of immune cells due to elevated chemokines CCL19 and CCL21. This synergy promoted immune memory, reducing the likelihood of recurrence.

CONCLUSIONS

M-HIFU effectively promotes the migration of DC vaccines through CCL19/21, presenting a promising approach for cancer treatment. Further studies are recommended to optimize this combination for clinical applications, with potential to improve patient outcomes in challenging cancer types.

Detection of Salmonella genes in stool samples of children aged 5 years and younger in urban and rural areas of Bangladesh

INTRODUCTION

Typhoid incidence in children is higher in urban areas than in rural areas of Bangladesh. This study examined whether healthy urban children harboured higher levels of Salmonella genes than healthy rural children.

METHODOLOGY

Stool samples from 140 children were studied: 70 from rural areas and 70 from urban metropolitan areas.

RESULTS

The stool samples of urban children contained more Salmonella genes (median 4, IQR 3-4) than those of rural children (median 3, IQR 3-4). This suggests that urban Bangladeshi children have more Salmonella genes in their guts than rural children. Especially, in those under 12 months of age, the Salmonella gene prevalence in urban children was unique. They had more Salmonella genes (median 4, IQR 4-5) than rural children in the same age group (median 3, IQR 2.5-4). We also found more Salmonella genes in urban children who drank tap water (median 4, IQR 3-5) than in rural children whose water source was tube well water (median 3, IQR 2-4) and boiled pond water (median 3, IQR 3-3.5). However, there was no significant difference of Salmonella genes between urban children who drank tap-water and children whose water source was a tube well (median 4, IQR 3-4).

CONCLUSIONS

These data suggest that the urban environment, including the drinking water supply system, increases the likelihood of healthy children in urban areas harbouring more potentially pathogenic Salmonella organisms in their gut than found in rural healthy children.

Safety, Tolerability and Pharmacokinetics of Intravenous Sodium Taurodeoxycholate, HY209, a GPCR19 Agonist Inhibiting Inflammasomal Activation

Background

HY209 is a synthesized sodium taurodeoxycholate (TDCA) that is expected to serve as a novel treatment for sepsis by inhibiting the inflammasomal activation that suppresses the production of pro-inflammatory cytokines. This study aimed to assess the safety, tolerability and pharmacokinetics (PKs) of HY209 after intravenous administration in healthy subjects.

Methods

A dose-block randomized, double-blind, placebo-controlled, single ascending dose study was conducted. Eight subjects in each dose group were randomized to receive an intravenous administration of HY209 (0.1, 0.2, 0.4, 0.8 and 1.6 mg/kg) or a placebo at a 3:1 ratio. Safety and tolerability variables including adverse events (AEs) and vital signs were monitored. For the PK analysis, serial blood samples were collected for 72 hours at baseline and up to 24 hours post-dose. A power model was used to evaluate the dose-proportionality of HY209. Given that TDCA is an endogenous compound, time-matched baseline differences in plasma concentrations were analyzed.

Results

A total of 39 subjects completed the study. All AEs were mild, and no serious AEs were observed. There was no significant correlation between the frequency of AEs and the administered dose. A circadian pattern was observed in the plasma TDCA concentration at baseline. After infusion, the plasma TDCA was rapidly eliminated; the plasma TDCA concentration at one hour after the end of infusion showed no significant differences from the baseline. The baseline-adjusted maximum plasma concentration of TDCA demonstrated dose-proportionality in a HY209 range of 0.1-1.6 mg/kg.

Conclusion

A single intravenous administration of HY209 was well tolerated and its systemic exposure showed dose-proportionality in a dose range between 0.1 and 1.6 mg/kg.

T-track PCR fingerprinting for the rapid detection of genetic polymorphism

The diversity of DNA sequences can be analyzed by comparing randomly amplified polymorphic DNA, or restriction fragment length polymorphism fragments of DNA. Such analyses are dependent on the selection of appropriate restriction enzyme(s) and/or primers. We have investigated a simpler approach to providing sensitive and specific genotyping. Cyclic extension of target sequences with dideoxythymidine generates PCR products with variable lengths. We analyzed these variable PCR products by scoring the number of variable bands and comparing the scores (numerical profiles) to establish similarities. We found that the polymorphic lengths of the PCR products were comparable among serologically defined strains. It suggests that this single PCR reaction followed by a one-step electrophoresis yields easily analyzable data that can be compared with data from other gels.