Special Issue "New Developments in Natural Killer Cells for Immunotherapy"

Tyndallized bacteria prime bronchial epithelial cells to mount an effective innate immune response against infections

Airway epithelium represents a physical barrier against toxic substances and pathogens but also presents pattern recognition receptors on the epithelial cells that detect pathogens leading to molecule release and sending signals that activate both the innate and adaptive immune responses. Thus, impaired airway epithelial function and poor integrity may increase the recurrence of infections. Probiotic use in respiratory diseases as adjuvant of traditional therapy is increasingly widespread. There is growing interest in the use of non-viable heat-killed bacteria, such as tyndallized bacteria (TB), due to safety concerns and to their immunomodulatory properties. This study explores in vitro the effects of a TB blend on the immune activation of airway epithelium. 16HBE bronchial epithelial cells were exposed to different concentrations of TB. Cell viability, TB internalization, TLR2 expression, IL-6, IL-8 and TGF-βl expression/release, E-cadherin expression and wound healing were assessed. We found that TB were tolerated, internalized, increased TLR2, E-cadherin expression, IL-6 release and wound healing but decreased both IL-8 and TGF-βl release. In conclusion, TB activate TLR2 pathway without inducing a relevant pro-inflammatory response and improve barrier function, leading to the concept that TB preserve epithelial homeostasis and could be used as strategy to prevent and to manage respiratory infection, exacerbations included.

SIRT2 as a Potential Biomarker in Lung Adenocarcinoma: Implications for Immune Infiltration

SIRT2 play important roles in cell cycle and cellular metabolism in the development of non-small cell lung cancer (NSCLC), and SIRT2 exhibits its therapeutic effect on NSCLC tumors with high expression of SIRT2. Nevertheless, the clinical relevance of SIRT2 in lung adenocarcinoma (LUAD), particularly its impact on tumor growth and prognostic implications, remains obscure. This investigation entailed a comprehensive analysis of SIRT2 mRNA and protein expression levels in diverse tumor and corresponding healthy tissues, utilizing databases such as TIMER 2.0, UALCAN, and HPA. Prognostic correlations of SIRT2 expression in LUAD patients, stratified by distinct clinicopathological characteristics, were evaluated using the KM Plotter database. Additionally, the TCGA and TIMER 2.0 databases were employed to assess the relationship between SIRT2 and immune infiltration, as well as to calculate immunity, stromal, and estimation scores, thus elucidating the role of SIRT2 in modulating tumor immunotherapy responses. Furthermore, Gene Set Enrichment Analysis (GSEA) was utilized to elucidate SIRT2's biological functions in pan-cancer cells. Our findings revealed a marked reduction in both mRNA and protein levels of SIRT2 in LUAD tumors relative to healthy tissue. Survival analysis indicated that diminished SIRT2 expression correlates with adverse prognostic outcomes in LUAD. Furthermore, SIRT2 expression demonstrated a significant association with various clinicopathologic attributes of LUAD patients, influencing survival outcomes across different clinicopathologic states. Functional enrichment analyses highlighted SIRT2's involvement in cell cycle regulation and immune response. Notably, SIRT2 exhibited a positive correlation with immune cell infiltration, including natural killer (NK) cells, macrophages, and dendritic cells (DCs). In summary, SIRT2 was a potential prognostic biomarker for LUAD and and a new immunotherapy target.

Developing oxaliplatin and IL-15 Co-carried gels as drug depots to enable triple-interlocked combination therapy for colorectal cancer

Chemo-immunotherapy, which involves the simultaneous use of chemotherapy drug and immunotherapeutic agent to achieve synergistic effects, plays a crucial role in cancer treatment. However, the immunosuppressive microenvironment, insufficient tumor specificity, and serious systemic side effects hinder their synergistic therapeutic effects and clinical applications. Herein, T cell and natural killer (NK) cell, which are the most important immune effector cells, were both activated to reverse the immunosuppressive microenvironment. To simplify drug carriers, oxaliplatin was selected as the chemotherapy drug which can both induce the ICD effect and activate T cells. IL-15 was selected to activate NK cells. To enhance the productivity of the carrier and reduce side effects, the easy-prepared thermosensitive hydrogel (OXL/IL-15 TG) was developed to co-load oxaliplatin-loaded liposomes (OXL) and IL-15. Colorectal cancer, suitable for in situ administration, was selected as model cancer. The resulting novel triple-interlocked combination therapy could directly kill the tumor cells, induces ICD effect and activate NK cells. After administration, OXL/IL-15 TG was formed serving as a drug depot, slowing releasing OXL and IL-15 non-interferencely. OXL around 165.47±7.04 nm was passively delivered to tumor tissue, killing tumor cells and inducing ICD effect. The results demonstrated that IL-15 stimulated the activation of NK cells. In tumor-bearing mice models, OXL/IL-15 TG exhibited a remarkable and noteworthy anti-tumor efficacy, and expanded survival rate. Notably, OXL/IL-15 TG led to an enhanced infiltration of CD3+CD8+ T cells and CD3-CD49+ NK cells within the tumor tissue. Overall, the triple-interlocked combination therapy provided a new idea for colorectal cancer therapy.

Comprehensive analysis reveals that LTBR is a immune-related biomarker for glioma

Glioma is a common malignant brain tumor with great heterogeneity and huge difference in clinical outcomes. Although lymphotoxin (LT) beta receptor (LTBR) has been linked to immune system and response development for decades, the expression and function in glioma have not been investigated. To confirm the expression profile of LTBR, integrated RNA-seq data from glioma and normal brain tissues were analyzed. Functional enrichment analysis, TMEscore analysis, immune infiltration, the correlation of LTBR with immune checkpoints and ferroptosis, and scRNAseq data analysis in gliomas were in turn performed, which pointed out that LTBR was pertinent to immune functions of macrophages in gliomas. In addition, after being trained and validated in the tissue samples of the integrated dataset, an LTBR DNA methylation-based prediction model succeeded to distinguish gliomas from non-gliomas, as well as the grades of glioma. Moreover, by virtue of the candidate LTBR CpG sites, a prognostic risk-score model was finally constructed to guide the chemotherapy, radiotherapy, and immunotherapy for glioma patients. Taken together, LTBR is closely correlated with immune functions in gliomas, and LTBR DNA methylation could serve as a biomarker for diagnosis and prognosis of gliomas.

Investigation of NK cell function against two target hematological cell line using radioactive chromium assay

NK (Natural killer) cells are a special population of peripheral blood lymphocytes that kill virus-infected cells as well as tumor cells. For testing NK cell function, the classic gold standard assay has been used for a long time, determining the activity from target tumor cells using radioactive chromium in cell cultures for 4h. In this study two hematological cell lines K562 and MDS where used and target and results showed different sensitivity to killing by NK cells separated from healthy volunteers. Results have been shown that MDS release significantly more radioactive chromium indicating higher degree of necrosis during cell culture. In addition, K562 cell line is better target for NK killing in all different E:T ratio in comparison to MDS cell line previously described. Based on this, it is suggested that K562 cells be continues used in the future as better target for investigation NK killing.

NK cells and the profile of inflammatory cytokines in the peripheral blood of patients with advanced carcinomas

BACKGROUND

Natural killer (NK) cells are one of the most crucial immune cells that mediate the antitumoral response due to their ability to immediately recognize and eliminate transformed cells. Because of their great cytotoxic activity, the function of NK cells must be robustly regulated to avoid tissue damage. Such regulation is mediated by a coordinated engagement of activating (NKp46) and inhibitory (CD158b) receptors, which tumor cells may use to escape from immunosurveillance. Also, NK cells are generally divided based on surface molecules, such as CD16 and CD56, and can be classified as CD56brightCD16- (regulatory) and CD56dimCD16+ (cytotoxic) NK cells. Here, we aimed to evaluate the frequency and phenotype of circulating NK cells in patients with advanced carcinomas, as well as their systemic cytokine/chemokine and growth factors production.

METHODS

Peripheral blood was collected from 24 patients with advanced solid cancer during or after treatment and from 10 healthy donors. The frequency and the expression of activating (NKp46) and inhibitory (CD158b) molecules of CD56brightCD16- and CD56dimCD16+ NK cells were assessed by flow cytometry and the multiplex Luminex platform was used to quantify the secreted factors in peripheral blood serum.

RESULTS

Cancer patients had a lower frequency of the cytotoxic CD56dim CD16+ NK cells subset in comparison with healthy controls. Also, the regulatory CD56bright CD16- NKs isolated from cancer patients exhibited a significantly lower expression of NKp46. Among 29 immunological and growth factors analyzed in the peripheral blood of oncologic patients, MCP-1, IP-10, and eotaxin, and VEGF they have presented a higher proportion. The Pearson correlation test showed that IL-12p40 positively correlates with CD56brightCD16- NK cells. We also observed a positive correlation between MCP-1 and the activating marker NKp46, as well as a negative correlation between IP-10 and TNF-α and NKp46. CD158b expression in CD56dimCD16+ was positively correlated with EGF and negatively correlated with MIP-1β.

CONCLUSIONS

Taken together, these results suggest that cancer patients present a shift towards a poorly cytotoxic and less activated NK profile which may contribute to tumor development and progression. The understanding of NK cell biology and soluble factors during tumor development could aid in the design of possible targeting therapeutic approaches.

A trispecific antibody induces potent tumor-directed T-cell activation and antitumor activity by CD3/CD28 co-engagement

Aim: A novel CD19xCD3xCD28 trispecific antibody with a tandem single-chain variable fragments (scFv) structure was developed for the treatment of B-cell malignancies. Methods: The trispecific antibody in inducing tumor-directed T-cell activation and cytotoxicity was evaluated in vitro and in vivo and compared with its bispecific counterpart BiTE-CD19xCD3 lacking a CD28-targeting domain. Results: The trispecific antibody with a co-stimulatory domain exhibited augmented T-cell activation and memory T-cell differentiation capability and it induced faster tumor cell lysis than the bispecific antibody. RNAseq analysis revealed that the trispecific antibody modulates CD3/TCR complex-derived signal and upregulates antiapoptotic factors to influence the survival of T cells. Conclusion: By CD3/CD28 co-engagement, the trispecific antibody demonstrated its advantages in T-cell immunity and potential use as a more powerful and long-lasting T-cell engager.

Allogeneic CAR-T Therapy Technologies: Has the Promise Been Met?

This last decade, chimeric antigen receptor (CAR) T-cell therapy has become a real treatment option for patients with B-cell malignancies, while multiple efforts are being made to extend this therapy to other malignancies and broader patient populations. However, several limitations remain, including those associated with the time-consuming and highly personalized manufacturing of autologous CAR-Ts. Technologies to establish "off-the-shelf" allogeneic CAR-Ts with low alloreactivity are currently being developed, with a strong focus on gene-editing technologies. Although these technologies have many advantages, they have also strong limitations, including double-strand breaks in the DNA with multiple associated safety risks as well as the lack of modulation. As an alternative, non-gene-editing technologies provide an interesting approach to support the development of allogeneic CAR-Ts in the future, with possibilities of fine-tuning gene expression and easy development. Here, we will review the different ways allogeneic CAR-Ts can be manufactured and discuss which technologies are currently used. The biggest hurdles for successful therapy of allogeneic CAR-Ts will be summarized, and finally, an overview of the current clinical evidence for allogeneic CAR-Ts in comparison to its autologous counterpart will be given.

Suppression of NK Cell Activation by JAK3 Inhibition: Implication in the Treatment of Autoimmune Diseases

Natural killer (NK) cell is an essential cytotoxic lymphocyte in our innate immunity. Activation of NK cells is of paramount importance in defending against pathogens, suppressing autoantibody production and regulating other immune cells. Common gamma chain (γc) cytokines, including IL-2, IL-15, and IL-21, are defined as essential regulators for NK cell homeostasis and development. However, it is inconclusive whether γc cytokine-driven NK cell activation plays a protective or pathogenic role in the development of autoimmunity. In this study, we investigate and correlate the differential effects of γc cytokines in NK cell expansion and activation. IL-2 and IL-15 are mainly responsible for NK cell activation, while IL-21 preferentially stimulates NK cell proliferation. Blockade of Janus tyrosine kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway by either JAK inhibitors or antibodies targeting γc receptor subunits reverses the γc cytokine-induced NK cell activation, leading to suppression of its autoimmunity-like phenotype in vitro. These results underline the mechanisms of how γc cytokines trigger autoimmune phenotype in NK cells as a potential target to autoimmune diseases.

Case report: Herbal treatment of neutropenic enterocolitis after chemotherapy for breast cancer

In this case report, a 53-year-old woman was diagnosed with severe NE after receiving chemotherapy for breast cancer. The patient with breast cancer was treated with a single cycle of docetaxel (140 mg) + epirubicin (130 mg) + cyclophosphamide (0.9 g) chemotherapy. However, the woman presented with symptoms of fatigue and diarrhea 5 days later accompanied with severe neutropenia according to the routine blood test. The computed tomography examination displayed the thickening and swelling of the colorectal wall. After the diagnosis of NE, the woman received antibiotics and supportive treatment, but her symptoms were not improved. The Chinese herbal medicine (CHM) diagnostic pattern was then designed for the patient. The patient was administered with two CHM decoctions. One decoction contained 24 kinds of herbal materials, and the other one was called pure ginseng decoction. These two decoctions were administered to the patient 2 or 3 times per day to tonify the spleen, nourish Qi and blood, and remove phlegm and damp heat symptoms. After the CHM treatment lasting for 10 days, the symptoms of the patient were improved, and she was discharged. In conclusion, CHM treatment played an indispensable role in curing the woman with chemotherapy-induced NE.

The involvement of circulating CD69+ CD56bright natural killer cells in weight loss before bariatric surgery: A retrospective cohort study

As the impact of the immune system on weight loss prior to bariatric surgery has never been proven, we elucidated the clinical utility of the immune system as an indicator of preoperative weight loss before bariatric surgery. We examined the relationships between preoperative weight loss and biochemical and clinical data at the initial visit in 34 obese patients. Patients were divided according to preoperative weight loss, and peripheral blood mononuclear cells were compared using flowcytometry. The Δpreoperative excess weight loss [Δpre-EWL: pre-EWL (%)/period of preoperative weight loss (days)] showed negative correlations with total and subcutaneous fat area (P = .02, r = -0.41, P = .02, r = -0.42 respectively). The Δpre-EWL and Δpreoperative total weight loss (Δpre-TWL) were negatively correlated with white blood cell count, lymphocyte count, and C-reactive protein (CRP) levels at the initial visit (Δpre-EWL; P = .02, r = -0.37, P = .01, r = -0.41, P = .008, r = -0.45, Δpre-TWL; P = .01, r = -0.40, P = .01, r = -0.42, P = .01, r = -0.42, respectively). Multivariate regression modeling showed that both Δpre-EWL and Δpre-TWL were significantly associated with lymphocyte count (Δpre-EWL; P = .01, Δpre-TWL; P = .01). A comparison between the high (Δ pre-EWL > 0.098) and low weight loss group (Δ pre-EWL < 0.098) demonstrated a significant difference in the expression of the activation marker CD69 on CD56bright Natural killer (NK) cells (P = .01), whereas there was no difference in the frequency of T cells, Natural killer T cells, or NK cells. Additionally, high CRP levels were associated with CD69 expression in CD56bright NK cells (P = .01, R = 0.57). Peripheral lymphocytes, especially CD69-positive CD56bright NK cells, are involved in preoperative weight loss after bariatric surgery, and systemic inflammation may inhibit weight loss before surgery.

Effects of Severe Acute Respiratory Syndrome Coronavirus Vaccination on Reinfection: A Community-Based Retrospective Cohort Study

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a disease that is characterized by frequent reinfection. However, the factors influencing reinfection remain poorly elucidated, particularly regarding the effect of COVID-19 vaccination on preventing reinfection and its effects on symptomatology and the interval until reinfection.

METHODS

This retrospective cohort study examined patients with severe acute respiratory syndrome coronavirus reinfection between January 2020 and February 2022. This study included patients aged >17 years who were reinfected at least 90 days between two infections with severe acute respiratory syndrome coronavirus. The main outcome measure was a reduction in symptoms during reinfection, and reinfection interval.

RESULTS

Overall, 712 patients (average age: 40.52 ± 16.41 years; 312 males) were included. The reduction rate of symptoms at reinfection than that at first infection was significantly higher in the vaccinated group than in the unvaccinated group (p < 0.001). The average reinfection interval was 265.81 days. The interval between the first and second infection was 63.47 days longer in the vaccinated group than in the unvaccinated group. The interval was also 57.23 days, significantly longer in the asymptomatic group than in the symptomatic group (p < 0.001).

CONCLUSIONS

Besides its role in preventing severe acute respiratory syndrome coronavirus infection, vaccination reduces the rate of symptomatic reinfection and increases the reinfection interval; thus, it is necessary to be vaccinated even after a previous infection. The findings may inform the decision to avail COVID-19 vaccination.