Not all vaping is the same: differential pulmonary effects of vaping cannabidiol versus nicotine.

RATIONALE: Vaping has become a popular method of inhaling various psychoactive substances. While evaluating respiratory effects of vaping have primarily focused on nicotine-containing products, cannabidiol (CBD)-vaping is increasingly becoming popular. It currently remains unknown whether the health effects of vaping nicotine and cannabinoids are similar. OBJECTIVES: This study compares side by side the pulmonary effects of acute inhalation of vaporised CBD versus nicotine. METHODS: In vivo inhalation study in mice and in vitro cytotoxicity experiments with human cells were performed to assess the pulmonary damage-inducing effects of CBD or nicotine aerosols emitted from vaping devices. MEASUREMENTS AND MAIN RESULTS: Pulmonary inflammation in mice was scored by histology, flow cytometry, and quantifying levels of proinflammatory cytokines and chemokines. Lung damage was assessed by histology, measurement of myeloperoxidase activity and neutrophil elastase levels in the bronchoalveolar lavage fluid and lung tissue. Lung epithelial/endothelial integrity was assessed by quantifying BAL protein levels, albumin leak and pulmonary FITC-dextran leak. Oxidative stress was determined by measuring the antioxidant potential in the BAL and lungs. The cytotoxic effects of CBD and nicotine aerosols on human neutrophils and human small airway epithelial cells were evaluated using in vitro air-liquid interface system. Inhalation of CBD aerosol resulted in greater inflammatory changes, more severe lung damage and higher oxidative stress compared with nicotine. CBD aerosol also showed higher toxicity to human cells compared with nicotine. CONCLUSIONS: Vaping of CBD induces a potent inflammatory response and leads to more pathological changes associated with lung injury than vaping of nicotine.

Do alternative tobacco products induce less adverse respiratory risk than cigarettes?

RATIONALE: Due to the relatively short existence of alternative tobacco products, gaps exist in our current understanding of their long-term respiratory health effects. We therefore undertook the first-ever side-by-side comparison of the impact of chronic inhalation of aerosols emitted from electronic cigarettes (EC) and heated tobacco products (HTP), and combustible cigarettes (CC) smoke. OBJECTIVES: To evaluate the potential differential effects of alternative tobacco products on lung inflammatory responses and efficacy of vaccination in comparison to CC. METHODS: Mice were exposed to emissions from EC, HTP, CC, or air for 8 weeks. BAL and lung tissue were analyzed for markers of inflammation, lung damage, and oxidative stress. Another group was exposed for 12 weeks and vaccinated and challenged with a bacterial respiratory infection. Antibody titers in BAL and sera and pulmonary bacterial clearance were assessed. MAIN RESULTS: EC- and HTP-aerosols significantly augmented lung immune cell infiltrates equivalent to that achieved following CC-exposure. HTP and CC significantly increased neutrophil numbers compared to EC. All products augmented numbers of B cells, T cells, and pro-inflammatory IL17A+ T cells in the lungs. Decreased lung antioxidant activity and lung epithelial and endothelial damage was induced by all products. EC and HTP differentially augmented inflammatory cytokines/chemokines in the BAL. Generation of immunity following vaccination was impaired by EC and HTP but to a lesser extent than CC, with a CC > HTP > EC hierarchy of suppression of pulmonary bacterial clearance. CONCLUSIONS: HTP and EC-aerosols induced a proinflammatory pulmonary microenvironment, lung damage, and suppressed efficacy of vaccination.

AT-RvD1 Mitigates Secondhand Smoke-Exacerbated Pulmonary Inflammation and Restores Secondhand Smoke-Suppressed Antibacterial Immunity.

Cigarette smoke is a potent proinflammatory trigger contributing to acute lung injury and the development of chronic lung diseases via mechanisms that include the impairment of inflammation resolution. We have previously demonstrated that secondhand smoke (SHS) exposure exacerbates bacterial infection-induced pulmonary inflammation and suppresses immune responses. It is now recognized that resolution of inflammation is a bioactive process mediated by lipid-derived specialized proresolving mediators that counterregulate proinflammatory signaling and promote resolution pathways. We therefore hypothesized that proresolving mediators could reduce the burden of inflammation due to chronic lung infection following SHS exposure and restore normal immune responses to respiratory pathogens. To address this question, we exposed mice to SHS followed by chronic infection with nontypeable Haemophilus influenzae (NTHI). Some groups of mice were treated with aspirin-triggered resolvin D1 (AT-RvD1) during the latter half of the smoke exposure period or during a period of smoking cessation and before infection. Treatment with AT-RvD1 markedly reduced the recruitment of neutrophils, macrophages, and T cells in lung tissue and bronchoalveolar lavage and levels of proinflammatory cytokines in the bronchoalveolar lavage. Additionally, treatment with AT-RvD1 improved Ab titers against the NTHI outer membrane lipoprotein Ag P6 following infection. Furthermore, treatment with AT-RvD1 prior to classically adjuvanted immunization with P6 increased Ag-specific Ab titers, resulting in rapid clearance of NTHI from the lungs after acute challenge. Collectively, we have demonstrated that AT-RvD1 potently reverses the detrimental effects of SHS on pulmonary inflammation and immunity and thus could be beneficial in reducing lung injury associated with smoke exposure and infection.

Specialized Proresolving Mediators Overcome Immune Suppression Induced by Exposure to Secondhand Smoke.

Tobacco smoke exposure is associated with multiple diseases including, respiratory diseases like asthma and chronic obstructive pulmonary disease. Tobacco smoke is a potent inflammatory trigger and is immunosuppressive, contributing to increased susceptibility to pulmonary infections in smokers, ex-smokers, and vulnerable populations exposed to secondhand smoke. Tobacco smoke exposure also reduces vaccine efficacy. Therefore, mitigating the immunosuppressive effects of chronic smoke exposure and improving the efficacy of vaccinations in individuals exposed to tobacco smoke, is a critical unmet clinical problem. We hypothesized that specialized proresolving mediators (SPMs), a class of immune regulators promoting resolution of inflammation, without being immunosuppressive, and enhancing B cell Ab responses, could reverse the immunosuppressive effects resulting from tobacco smoke exposure. We exposed mice to secondhand smoke for 8 wk, followed by a period of smoke exposure cessation, and the mice were immunized with the P6 lipoprotein from nontypeable Haemophilus influenzae, using 17-HDHA and aspirin-triggered-resolvin D1 (AT-RvD1) as adjuvants. 17-HDHA and AT-RvD1 used as adjuvants resulted in elevated serum and bronchoalveolar lavage levels of anti-P6-specific IgG and IgA that were protective, with immunized mice exhibiting more rapid bacterial clearance upon challenge, reduced pulmonary immune cell infiltrates, reduced production of proinflammatory cytokines, and less lung-epithelial cell damage. Furthermore, the treatment of mice with AT-RvD1 during a period of smoke-cessation further enhanced the efficacy of SPM-adjuvanted P6 vaccination. Overall, SPMs show promise as novel vaccine adjuvants with the ability to overcome the tobacco smoke-induced immunosuppressive effects.

Importance of myeloid derived suppressor cells in cancer from a biomarker perspective.

Myeloid derived suppressor cells (MDSC) are a heterogenous population of immature myeloid cells that accumulate in tumor bearing host and migrate to lymphoid organs and tumor tissues. This process is controlled by a set of defined pro-inflammatory cytokines and chemokines, which are upregulated in malignancies. MDSC have strong immunosuppressive potential and constitute a major component of the tumor microenvironment (TME). Tumor cells take advantage of the suppressive mechanisms of MDSC to establish an immunosuppressive TME which inhibits antitumor immune responses thereby promoting cancer progression. An immunosuppressive TME acts as a significant barrier to immunotherapeutic interventions. Pre-clinical and clinical studies have demonstrated that enrichment and activation of MDSC is correlated with tumor progression, recurrence and metastasis. In this review we discuss the potential impact of MDSC on tumor progression and its role as a biomarker of prognostic significance in cancer with a special focus on hepatocellular cancer (HCC).

Acute Effects of Heated Tobacco Product (IQOS) Aerosol Inhalation on Lung Tissue Damage and Inflammatory Changes in the Lungs.

INTRODUCTION: Emerging heated tobacco products (HTPs) were designed to reduce exposure to toxicants from cigarette smoke (CS) by avoiding burning tobacco and instead heating tobacco. We studied the effects of short-term inhalation of aerosols emitted from HTP called IQOS, on lung damage and immune-cell recruitment to the lungs in mice. METHODS: Numerous markers of lung damage and inflammation including albumin and lung immune-cell infiltrates, proinflammatory cytokines, and chemokines were quantified in lungs and bronchoalveolar (BAL) fluid from IQOS, CS, or air-exposed (negative control) mice. RESULTS: Importantly, as a surrogate marker of lung epithelial-cell damage, we detected significantly increased levels of albumin in the BAL fluid of both HTP- and CS-exposed mice compared with negative controls. Total numbers of leukocytes infiltrating the lungs were equivalent following both IQOS aerosols and CS inhalation and significantly increased compared with air-exposed controls. We also observed significantly increased numbers of CD4+IL-17A+ T cells, a marker of a T-cell immune response, in both groups compared with air controls; however, numbers were the highest following CS exposure. Finally, the numbers of CD4+RORγt+ T cells, an inflammatory T-cell subtype expressing the transcription factor that is essential for promoting differentiation into proinflammatory Th17 cells, were significantly augmented in both groups compared with air-exposed controls. Levels of several cytokines in BAL were significantly elevated, reflecting a proinflammatory milieu. CONCLUSIONS: Our study demonstrates that short-term inhalation of aerosols from IQOS generates damage and proinflammatory changes in the lung that are substantially similar to that elicited by CS exposure. IMPLICATIONS: Exposure of mice to IQOS, one of the candidate modified-risk tobacco products, induces inflammatory immune-cell accumulation in the lungs and augments the levels of proinflammatory cytokines and chemokines in the BAL fluid. Such an exacerbated pulmonary proinflammatory microenvironment is associated with lung epithelial-cell damage in IQOS-exposed mice, suggesting a potential association with the impairment of lung function.

Secondhand Smoke Induces Inflammation and Impairs Immunity to Respiratory Infections.

Despite advocacy to reduce smoking-related diseases, >1 billion people worldwide continue to smoke. Smoking is immunosuppressive and an important etiological factor in the development of several human disorders including respiratory diseases like chronic obstructive pulmonary disease. However, there is a critical gap in the knowledge of the role of secondhand smoke (SHS) in inflammation and immunity. We therefore studied the influence of SHS on pulmonary inflammation and immune responses to respiratory infection by nontypeable Haemophilus influenzae (NTHI) recurrently found in chronic obstructive pulmonary disease patients. Chronic SHS-exposed mice were chronically infected with NTHI and pulmonary inflammation was evaluated by histology. Immune cell numbers and cytokines were measured by flow cytometry and ELISA, respectively. Chronic SHS exposure impaired NTHI P6 Ag-specific B and T cell responses following chronic NTHI infection as measured by ELISPOT assays, reduced the production of Abs in serum and bronchoalveolar lavage, and enhanced albumin leak into the bronchoalveolar lavage as determined by ELISA. Histopathological examination of lungs revealed lymphocytic accumulation surrounding airways and bronchovasculature following chronic SHS exposure and chronic infection. Chronic SHS exposure enhanced the levels of inflammatory cytokines IL-17A, IL-6, IL-1ß, and TNF-α in the lungs, and impaired the generation of adaptive immunity following either chronic infection or P6 vaccination. Chronic SHS exposure diminished bacterial clearance from the lungs after acute NTHI challenge, whereas P6 vaccination improved clearance equivalent to the level seen in air-exposed, non-vaccinated mice. Our study provides unequivocal evidence that SHS exposure has long-term detrimental effects on the pulmonary inflammatory microenvironment and immunity to infection and vaccination.

High immunosuppressive burden in cancer patients: a major hurdle for cancer immunotherapy.

A bottleneck for immunotherapy of cancer is the immunosuppressive microenvironment in which the tumor cells are located. Regardless of the fact that large numbers of tumor-specific T cells can be generated in patients by active immunization or adoptive transfer, these T cells do not readily translate to tumor cell killing in vivo. The immune regulatory mechanism that prevents autoimmunity may be harnessed by tumor cells for the evasion of immune destruction. Regulatory T cells, myeloid-derived suppressor cells, inhibitory cytokines and immune checkpoint receptors are the major components of the immune system acting in concert with causing the subversion of anti-tumor immunity in the tumor microenvironment. This redundant immunosuppressive network may pose an impediment to efficacious immunotherapy, thus facilitating tumor progression. Cancer progression clearly documents the failure of immune control over relentless growth of tumor cells. Detailed knowledge of each of these factors responsible for creating an immunosuppressive shield to protect tumor cells from immune destruction is essential for the development of novel immune-based therapeutic interventions of cancer. Multipronged targeted depletion of these suppressor cells may restore production of granzyme B by CD8(+) T cells and increase the number of IFN-γ-producing CD4(+) T cells.

Cigarette smoke exposure exacerbates lung inflammation and compromises immunity to bacterial infection.

The detrimental impact of tobacco on human health is clearly recognized, and despite aggressive efforts to prevent smoking, close to one billion individuals worldwide continue to smoke. People with chronic obstructive pulmonary disease are susceptible to recurrent respiratory infections with pathogens, including nontypeable Haemophilus influenzae (NTHI), yet the reasons for this increased susceptibility are poorly understood. Because mortality rapidly increases with multiple exacerbations, development of protective immunity is critical to improving patient survival. Acute NTHI infection has been studied in the context of cigarette smoke exposure, but this is the first study, to our knowledge, to investigate chronic infection and the generation of adaptive immune responses to NTHI after chronic smoke exposure. After chronic NTHI infection, mice that had previously been exposed to cigarette smoke developed increased lung inflammation and compromised adaptive immunity relative to air-exposed controls. Importantly, NTHI-specific T cells from mice exposed to cigarette smoke produced lower levels of IFN-γ and IL-4, and B cells produced reduced levels of Abs against outer-membrane lipoprotein P6, with impaired IgG1, IgG2a, and IgA class switching. However, production of IL-17, which is associated with neutrophilic inflammation, was enhanced. Interestingly, cigarette smoke-exposed mice exhibited a similar defect in the generation of adaptive immunity after immunization with P6. Our study has conclusively demonstrated that cigarette smoke exposure has a profound suppressive effect on the generation of adaptive immune responses to NTHI and suggests the mechanism by which prior cigarette smoke exposure predisposes chronic obstructive pulmonary disease patients to recurrent infections, leading to exacerbations and contributing to mortality.

T-regulatory cells and programmed death 1+ T cells contribute to effector T-cell dysfunction in patients with chronic obstructive pulmonary disease.

RATIONALE: Previous studies from our laboratory have shown that peripheral blood mononuclear cells (PBMCs) from patients with chronic obstructive pulmonary disease (COPD) prone to exacerbations with nontypeable Haemophilus influenzae have impaired responses to lipoprotein P6. We hypothesized that an underlying immunosuppressive network could be responsible for the defective antibacterial immunity observed in these patients. We evaluated T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSC), and exhausted T effector cells (programmed death 1 [PD-1](+)) in patients with COPD, because these cells are known to play a pivotal role in suppressing immune responses. OBJECTIVES: We performed an in-depth characterization of Tregs, T effector cells, and MDSC in COPD and correlated their levels and function with disease severity. METHODS: Treg, effector T cell, and MDSC frequency from patients with COPD and healthy subjects' PBMCs were analyzed by flow cytometry. Treg immunosuppressive capacity was measured by in vitro suppression assay. The frequency of interferon-γ producing T cells and T-cell proliferation were measured after blocking CTLA-4 and PD-1. Plasma proinflammatory and immunosuppressive cytokine levels were measured. MEASUREMENTS AND MAIN RESULTS: Significantly increased levels of Tregs, MDSC, and PD-1(+) exhausted effector T cells were present in patients with COPD compared with healthy subjects. Tregs from patients with COPD suppressed P6-specific T-cell proliferation to a greater extent than Tregs from healthy subjects. Plasma levels of Treg-generated cytokines, IL-10, and transforming growth factor-ß were elevated. Blockade of CTLA-4 resulted in significant augmentation of T-cell IFN-γ production in patients with COPD. CONCLUSIONS: Functionally suppressive Tregs, MDSCs, and exhausted PD-1(+) T cells contribute to effector T-cell dysfunction in COPD.

Targeted therapy in gastrointestinal malignancies.

Increased understanding of cancer pathogenesis has identified several pathways that serve as potential targets for novel targeted agents in development. The selection of targeted cancer therapy based on biomarkers has instigated a new era of personalized medicine and changed the way we practice oncology. Many targeted agents are approved for treatment of gastrointestinal malignancies most targeting tumor angiogenesis, and many more are in different phases of development. Here we briefly summarize nine different targeted agents that are approved currently in the U.S. and several other agents currently being studied in various gastrointestinal cancers.

Challenges in current inhalable tobacco toxicity assessment models: A narrative review.

Emerging tobacco products such as electronic nicotine delivery systems (ENDS) and heated tobacco products (HTPs) have a dynamic landscape and are becoming widely popular as they claim to offer a low-risk alternative to conventional smoking. Most pre-clinical laboratories currently exploit in vitro, ex vivo, and in vivo experimental models to assess toxicological outcomes as well as to develop risk-estimation models. While most laboratories have produced a wide range of cell culture and mouse model data utilizing current smoke/aerosol generators and standardized puffing profiles, much variation still exists between research studies, hindering the generation of usable data appropriate for the standardization of these tobacco products. In this review, we discuss current state-of-the-art in vitro and in vivo models and their challenges, as well as insights into risk estimation of novel products and recommendations for toxicological parameters for reporting, allowing comparability of the research studies between laboratories, resulting in usable data for regulation of these products before approval by regulatory authorities.

Anti-inflammatory IgG production requires functional P1 promoter in ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1) gene.

The anti-inflammatory properties associated with intravenous immunoglobulin therapy require the sialic acid modification of the N-glycan of the Fc domain of IgG. Sialylation of the Fc fragment is mediated by ß-galactoside α2,6-sialyltransferase 1 (ST6Gal-1), acting on the Gal(ß4)GlcNAc terminal structure of the biantennary N-glycans on the Fc domain. However, little is known regarding the in vivo regulation of Fc sialylation and its role in the progression of inflammatory processes. Here, we report that decreased Fc sialylation of circulatory IgG accompanies the acute phase response elicited by turpentine exposure or upon acute exposure to either nontypeable Haemophilus influenzae or ovalbumin. However, Fc sialylation was increased 3-fold from the base line upon transition to chronic inflammation by repeated exposure to challenge. The P1 promoter of the ST6Gal-1 gene is critical for Fc sialylation, but P1 does not drive ST6Gal-1 expression in B cells. The Siat1ΔP1 mouse, with a dysfunctional P1 promoter, was unable to produce sialylated Fc in the systemic circulation, despite the presence of Gal(ß4)GlcNAc termini on the Fc glycans. The major contribution of P1 action is to synthesize ST6Gal-1 enzymes that are deposited into the systemic circulation. The data strongly indicate that this pool of extracellular ST6Gal-1 in the blood impacts the sialylation of IgG Fc and that defective Fc sialylation is likely a major contributing mechanism for the proinflammatory tendencies previously noted in Siat1ΔP1 animals.

Single low-dose un-adjuvanted HBsAg nanoparticle vaccine elicits robust, durable immunity.

Chitosan nanoparticles were evaluated as a vaccine delivery system for hepatitis B surface antigen (HBsAg) in the absence of adjuvant. Nano-encapsulated HBsAg (HBsAg chitosan-NP) was endocytosed more rapidly and efficiently by dendritic cells compared to soluble HBsAg. FRET analysis demonstrated that intact nanoparticles were taken up by DCs. To determine the immunogenicity of adjuvant-free nano-encapsulated HBsAg, mice were immunized with a single dose of non-encapsulated HBsAg, HBsAg chitosan-NP, or HBsAg alum. Mice immunized with adjuvant-free nanoparticle elicited anti-HBs antibodies at significantly higher titers compared to mice immunized with HBsAg alum. Elevated numbers of BAFF-R(+) B cells and CD138+ plasma cells account for the heightened anti-HBs response in nanoparticle immunized mice. Increases in Tfh cells provide a mechanism for the accumulation of anti-HBs secreting cells. Thus, chitosan nanoparticle vaccines represent a promising un-adjuvanted platform to generate robust and durable immunity to HBsAg and other subunit antigens following a single low-dose administration. FROM THE CLINICAL EDITOR: In this study, chitosan nanoparticle vaccines are demonstrated as a promising un-adjuvanted platform to generate robust and durable immunity to HBsAg and other subunit antigens following a single low-dose administration in a murine model. The authors also demonstrated superior antibody response induction compared with non-encapsulated HBs antigen and HBsAg aluminum.

Nrf2 regulates chronic lung inflammation and B-cell responses to nontypeable Haemophilus influenzae.

Nrf2 is a leucine zipper transcription factor that protects against oxidant-induced injury. Nontypeable Haemophilus influenzae is responsible for frequent disease exacerbations in patients with chronic obstructive pulmonary disease and is responsible for causing otitis media in young children. We hypothesized that Nrf2 would limit inflammatory responses to nontypeable H. influenzae. The objective of this study was to assess the role of Nrf2 in chronic lung inflammation and regulation of immune responses to nontypeable H. influenzae in mice. Wild-type (C57BL/6) mice and Nrf2(-/-) mice were instilled by oropharyngeal aspiration of 1 × 10(6) colony-forming units of live, nontypeable H. influenzae (NTHI) twice a week for 4 to 16 consecutive weeks to generate a chronic inflammatory milieu within the lungs that models chronic bronchitis. Nrf2(-/-) mice had increased lymphocytic airway inflammation compared with WT mice after NTHI challenge. Although the extent of NTHI-induced peribronchovascular inflammation did not significantly differ between the genotypes, plasma cell infiltration was significantly more abundant in Nrf2(-/-) mice. Most strikingly, Nrf2(-/-) mice generated significantly enhanced and persistent levels of serum antibodies against P6, a key outer membrane protein of NTHI. Lung dendritic cells from Nrf2(-/-) mice challenged with NTHI had increased activation markers compared with dendritic cells from similarly treated WT mice. Nrf2 regulates NTHI-induced airway inflammation characterized by lymphocytic and plasma cell infiltration and the activation of lung dendritic cells and B-cell responses in mice. Nrf2 may be a potential therapeutic target in limiting the bacterial infection-induced airway inflammation that drives exacerbations of chronic obstructive pulmonary disease.

Murine model of chronic respiratory inflammation.

The respiratory mucosa is exposed to the external environment each time we breathe and therefore requires a robust and sophisticated immune defense system. As with other mucosal sites, the respiratory mucosal immune system must balance its response to pathogens while also regulating inflammatory immune cell-mediated tissue damage. In the airways, a failure to tightly control immune responses to a pathogen can result in chronic inflammation and tissue destruction with an overzealous response being deleterious for the host. Chronic obstructive pulmonary disease (COPD) is the fourth most common cause of death in the US and both the prevalence of and mortality rate of this disease is increasing annually. COPD is characterized by intermittent disease exacerbation. The causal contribution of bacterial infections to exacerbations of COPD is now widely accepted, accounting for at least 50% of all exacerbations. Non-typeable Haemophilus influenzae and Moraxella catarrhalis (both gram-negative bacteria) along with Streptococcus pneumoniae (a gram-positive bacterium) are the three most common bacterial pathogens that cause respiratory tract infections in COPD patients. The colonization of bacteria in the lower airways is similar to a low-grade smoldering infection that induces chronic airway inflammation. Chronic low-grade infection can induce a persistent inflammatory response in the airways and parenchyma. Inefficient removal of bacteria from the lower respiratory tract is characteristic of chronic bronchitis. Inflammation is believed to be central to the pathogenesis of exacerbations, but a clear understanding of the inflammatory changes during an exacerbation of COPD has yet to emerge. As bacterial colonization of the lung in COPD patients is a chronic inflammatory condition highlighted by frequent bouts of exacerbation and clearance, we sought to reproduce this chronic pathogen-mediated inflammation in a murine model by repeatedly delivering the intact, whole, live bacteria intra-tracheally to the lungs.

Natural Killer Cells and T Cells in Hepatocellular Carcinoma and Viral Hepatitis: Current Status and Perspectives for Future Immunotherapeutic Approaches.

Natural killer (NK) cells account for 25-50% of the total number of hepatic lymphocytes, which implicates that NK cells play an important role in liver immunity. The frequencies of both circulating and tumor infiltrating NK cells are positively correlated with survival benefit in hepatocellular cancer (HCC) and have prognostic implications, which suggests that functional impairment in NK cells and HCC progression are strongly associated. In HCC, T cell exhaustion is accompanied by the interaction between immune checkpoint ligands and their receptors on tumor cells and antigen presenting cells (APC). Immune checkpoint inhibitors (ICIs) have been shown to interfere with this interaction and have altered the therapeutic landscape of multiple cancer types including HCC. Immunotherapy with check-point inhibitors, aimed at rescuing T-cells from exhaustion, has been applied as first-line therapy for HCC. NK cells are the first line effectors in viral hepatitis and play an important role by directly eliminating virus infected cells or by activating antigen specific T cells through IFN-γ production. Furthermore, chimeric antigen receptor (CAR)-engineered NK cells and T cells offer unique opportunities to create CAR-NK with multiple specificities learning from the experience gained with CAR-T cells with potentially less adverse effects. This review focus on the abnormalities of NK cells, T cells, and their functional impairment in patients with chronic viral hepatitis, which contributes to progression to hepatic malignancy. Furthermore, we discuss and summarize recent advances in the NK cell and T cell based immunotherapeutic approaches in HCC.

Transgenic plant-based oral vaccines.

Oral vaccines offer significant advantages over needle-based vaccines for achieving universal childhood vaccination goals. The expression of vaccine antigens in transgenic plants has the potential to provide a convenient, safe approach for oral vaccination and thus a feasible alternative to traditional parenteral vaccines. Many developments in the field have ushered in improvements such as enhanced protein antigen expression for the use of plants as factories for vaccine production, and facilitated studies pertaining to immunogenicity of candidate vaccines. Oral delivery of plant-based vaccines offers the benefit of antigen protection within the harsh intestinal environment. Within the gut, mucosal immune cells are poised to respond to pathogens, but can also be exploited to elicit protective immune responses to oral vaccines. Inclusion of mucosal adjuvants during immunization with the vaccine antigen has been an important step towards the success of plant-based vaccines. This review discusses the mechanisms that control mucosal immune responses and highlights some of the studies and the results achieved following immunization with transgenic plants.

Tivozanib mediated inhibition of c-Kit/SCF signaling on Tregs and MDSCs and reversal of tumor induced immune suppression correlates with survival of HCC patients.

The immune modulatory effect of tivozanib, a tyrosine kinase inhibitor, and the underlying immune mechanisms impacting survival of HCC patients have not been investigated. Pre-clinical studies have shown that tivozanib reduces Tregs and MDSCs accumulation through inhibition of c-Kit/SCF axis. We rationalized that c-Kit/SCF axis antagonism by tivozanib may reverse tumor-induced immune suppression in HCC patients. The frequency of circulating Tregs, MDSCs, CTLA-4+Tregs, PD-1+T cells, c-Kit+pERK-2+Tregs, and c-Kit+pERK-2+MDSCs were quantified in HCC patients at baseline and two time points during tivozanib treatment. We report for the first time that reduction in Tregs after tivozanib treatment and increased levels of baseline CD4+PD-1+T cells correlated with significant improvement in overall survival (OS) of the patients and these signatures may be potential biomarkers of prognostic significance. This immune modulation resulted from tivozanib-mediated blockade of c-Kit/SCF signaling, impacting ERK2 phosphorylation on Tregs and MDSCs. Low pre-treatment CD4+T cells: Treg ratio and reduction in the frequencies of Foxp3+c-Kit+pERK+Tregs after tivozanib treatment correlated significantly with progression free survival. In a comparative analysis of tivozanib vs sorafenib treatment in HCC patients, we demonstrate that decrease in the baseline numbers or frequencies of Foxp3+Tregs, MDSCs and exhausted T cells was significantly greater following tivozanib treatment. Additionally, greater increase in CD4+T cell: Treg ratio after tivozanib treatment was associated with significant improvement in OS compared to sorafenib treatment, highlighting the greater efficacy of tivozanib. These insights may help identify patients who likely would benefit from c-Kit/SCF antagonism and inform efforts to improve the efficacy of tivozanib in combination with immunotherapy.