Diminished Frequencies of Cytotoxic Marker Expressing T- and NK Cells at the Site of Mycobacterium tuberculosis Infection

Potent induction of antitumor immunity by combining cryo-thermal ablation with immune checkpoint inhibitors in hepatocellular carcinoma

BACKGROUND

The low response rate of immune checkpoint inhibitors (ICIs) prompts the exploration of novel combination therapies for patients with hepatocellular carcinoma (HCC). Here, we aimed to examine the efficiency and potential mechanism of cryo-thermal ablation (Cryo-A) combined with anti-programmed death protein 1 (αPD1) and/or cytotoxic T-lymphocyte antigen 4 (αCTLA4) inhibitors in a murine hepatoma model.

METHOD

Immunocompetent C57BL/6 mice inoculated with unilateral or bilateral H22 hepatic tumour cells were treated with Cryo-A and/or ICIs (αPD1 and/or αCTLA4). Flow cytometry, immunohistochemistry, ELISpot assay, time-of-flight cytometry, tumour rechallenging, and T-cell depletion assay were used to assess the dynamic changes of immune cell subsets following therapy.

RESULTS

We found Cryo-A resulted in immunogenic cell death of tumour cells, activation of dendritic cells, and enhancement of antitumor immunity. Cryo-A alone was insufficient to extend survival, combining Cryo-A with αPD1 and αCTLA4 further modulated the tumour microenvironment, inducing a durable antitumor immune response by tumour-reactive CD8+ T cells and significantly prolonged survival. Time-of-flight cytometry (CyTOF) data revealed that combination therapies reshaped the tumour microenvironment by the increase of intratumoral CD8+ T cells expressed higher levels of cytotoxic markers and immune checkpoint molecules, and by downregulation of intratumoral granulocytes. The combination also resulted in the eradication of remote unablated tumours (abscopal effect).

CONCLUSIONS

These findings suggested that Cryo-A turned HCC from "cold" tumours to "hot" tumours and the combination of Cryo-A with αPD1 and αCTLA4 may be a promising approach to improve the prognosis of HCC.

Single cell analysis reveals a subset of cytotoxic-like plasmacytoid dendritic cells in people with HIV-1

Human plasmacytoid dendritic cells (pDCs) play a central role in initiating and activating host immune responses during infection. To understand how the transcriptome of pDCs is impacted by HIV-1 infection and exogenous stimulation, we isolated pDCs from healthy controls, people with HIV-1 (PWH) before and during toll-like receptor 9 (TLR9) agonist treatment and performed single-cell (sc)-RNA sequencing. Our cluster analysis revealed four pDC clusters: pDC1, pDC2, cytotoxic-like pDC and an exhausted pDC cluster. The inducible cytotoxic-like pDC cluster is characterized by high expression of both antiviral and cytotoxic genes. Further analyses confirmed that cytotoxic-like pDCs are distinct from NK and T cells. Cell-cell communication analysis also demonstrated that cytotoxic-like pDCs exhibit similar incoming and outgoing cellular communicating signals as other pDCs. Thus, our study presents a detailed transcriptomic atlas of pDCs and provides new perspectives on the mechanisms of regulation and function of cytotoxic-like pDCs.

CTLs, NK cells and NK-derived EVs against breast cancer

Patients with advanced stage breast cancer need novel therapies. New potential treatments have been developed, such as adoptive cellular therapies and alternative cell-free immunotherapies. The goal of this study was to assess the cytotoxicity of three of the patient-derived immune components, CTLs, NK cells and NK-derived EVs, and evaluate the potential for the development of novel therapy against breast cancer. CTLs were activated against MUC-1 antigen. The in vitro cytotoxic activity of three components was assessed with flow cytometry and in vivo study revealed the efficacy of adoptive cell therapy. Overall, CTLs exhibited the highest cytotoxicity against spheroids of MCF7 breast adenocarcinoma, reaching in all cases higher than double the percentage of NK cells' cytotoxicity. NK-derived EVs exhibited the lowest effect against MCF7 spheroids comparing to the two cell populations. MUC-1 specific CTLs were evaluated with adoptive cell therapy mice study and appeared to be well tolerable and moderately efficacious. More studies need to be performed with CTLs to evaluate safety and efficacy in order to assess their clinical potential, while NK cells and NK-derived EVs are promising candidates that require more experiments to enhance their cytotoxicity.

Dominant expansion of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines in culture-positive lymph node tuberculosis

Lymph node culture-positive tuberculosis (LNTB+) is associated with increased mycobacterial antigen-induced pro-inflammatory cytokine production compared to LN culture-negative tuberculosis (LNTB-). However, the frequencies of CD4+, CD8+ T cells and NK cells expressing Th1/Tc1/Type 1 (IFNγ, TNFα, IL-2), Th17/Tc17/Type 17 (IL-17A, IL-17F, IL-22) cytokines and cytotoxic (perforin [PFN], granzyme [GZE] B, CD107a) markers in LNTB+ and LNTB- individuals are not known. Thus, we have studied the unstimulated (UNS) and mycobacterial antigen-induced frequencies of CD4+, CD8+ T and NK cells expressing Th1, Th17 cytokines and cytotoxic markers using flow cytometry. The frequencies of CD4+, CD8+ T and NK cells expressing cytokines and cytotoxic markers were not significantly different between LNTB+ and LNTB- individuals in UNS condition. In contrast, upon Mtb antigen stimulation, LNTB+ individuals are associated with significantly increased frequencies of CD4+ T cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [IFNγ, TNFα, IL-2]), CD8+ T cells (PPD [IFNγ], ESAT-6 PP [IFNγ], CFP-10 PP [TNFα]) and NK cells (PPD [IFNγ, TNFα], ESAT-6 PP [IFNγ, TNFα], CFP-10 PP [TNFα]) expressing Th1/Tc1/Type 1, but not Th17/Tc17/Type 17 cytokines and cytotoxic markers compared to LNTB- individuals. LNTB+ individuals did not show any significant alterations in the frequencies of CD4+, CD8+ T cells and NK cells expressing cytokines and cytotoxic markers compared to LNTB- individuals upon HIV Gag PP and P/I antigen stimulation. Increased frequencies of CD4+, CD8+ T and NK cells expressing Th1/Tc1/Type 1 cytokines among the LNTB+ group indicates that the presence of mycobacteria plays a dominant role in the activation of key correlates of immune protection or induces higher immunopathology.

Ex-vivo immunophenotyping and high dimensionality UMAP analysis of leucocyte subsets in tuberculous lymphadenitis

Tuberculous lymphadenitis (TBL) is defined by reduced proinflammatory cytokines and elevated CD4⁺, CD8⁺ T cells and decreased CD8⁺ cytotoxic markers. However, ex-vivo phenotyping of diverse leucocytes in TBL has not been done. We show activated and atypical B cells, myeloid dendritic cells (mDCs), classical, non-classical and intermediate monocytes, T regulatory (T regs) cells, CD4⁺ T cell effector memory RA (TEMRA), CD4⁺ effector and CD8⁺ central memory phenotypes were significantly increased in TBL compared to LTB individuals. In contrast, classical memory and plasma B cells, plasmacytoid DCs (pDCs), CD8⁺ TEMRA, CD4⁺ naïve and central memory cells were significantly decreased in TBL compared to LTB individuals. Some of the leucocyte frequencies (atypical memory B cells, pDCs, myeloid-derived suppressor cells, CD4⁺ effector and CD8⁺ central memory was increased; activated memory and plasma B cell, mDCs, classical, non-classical, intermediate monocytes, T regs, CD4⁺ TEMRA, CD4⁺, CD8⁺ naïve and effector memory cells and CD8⁺ central memory cells were decreased) were significantly modulated after anti-TB treatment among TBL individuals. UMAP analysis show that leucocyte subsets or islands expressing specific markers were significantly different in TBL baseline and post-treatment individuals. Overall, we suggest altered frequencies of diverse leucocytes influences the disease pathology and protective immunity in TBL individuals.