Frequency Of Natural Killer T Cells Research Articles

Expansion of MAIT cells in the combined absence of NKT and γδ-T cells

Mucosal-associated invariant T (MAIT) cells, natural killer T (NKT) cells, and γδT cells are collectively referred to as 'unconventional T cells' due to their recognition of non-peptide antigens and restriction to non-classical MHC-I-like molecules. Though the frequencies of MAIT, NKT and γδT cells and distribution of their functional subsets vary widely between organs and individuals, the factors controlling these differences are poorly understood. Here, we show that MAIT cells are increased in mice deficient in either NKT or γδT cells and even more-so in mice deficient in both NKT and γδT cells. In addition, characterisation of the TCRα repertoire within γδT cell-deficient thymocytes revealed an altered Trav gene segment usage relative to that of WT thymocytes, highlighting a retention of the Tcra-Tcrd locus from 129 strain embryonic stem cells used to generate Tcrd-/- mice. Accordingly, this resulted in a moderate increase in distal Trav segment usage such as Trav1, potentially contributing to increased generation of Trav1-Traj33+ MAIT cells in the Tcrd-/- thymus. However, peripheral MAIT cells also underwent increased homeostatic proliferation in the absence of NKT and γδT cells and adoptively transferred MAIT cell subsets exhibited tissue-specific homing patterns. Collectively, our data reveals a shared niche for MAIT, NKT, and γδT cells, suggesting a competition for common factors that could be exploited for treating disease. Importantly, these data highlight that careful assessment of studies using NKT or γδT cell-deficient mouse models is required when investigating the role of unconventional T cells in disease.

P.227 Spatial memory impairments following imunotoxic lesion of GABAergic neurons of the basal forebrain

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

P.110 Study of the role of the matricellular protein hevin in major depression

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

P.224 Primary food cues engage pathways involved in over-eating and reward-seeking in rats

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

Natural Killer T Cells Are Numerically and Functionally Deficient in Patients with Trauma

Natural killer T (NKT) cells rapidly produce Th1 and Th2 cytokines such as interferon-γ (IFN-γ) and interleukin (IL)-4. This study examined the frequency and function of NKT cells in trauma patients. Frequencies, proliferative responses to α-galactosylceramide (α-GalCer), and Th1/Th2 cytokine secretion levels of NKT cells in peripheral blood mononuclear cells from trauma patients and healthy controls (HC) were measured by flow cytometry. Circulating NKT cell levels were significantly reduced in trauma patients. Proliferation and IFN-γ production of circulating NKT cells in response to α-GalCer were markedly decreased in trauma patients. CD69 expression levels produced by NKT cells were significantly upregulated in trauma patients compared to those in HC. In addition, annexin V+ NKT cells were profoundly increased in trauma patients after α-GalCer stimulation. Trauma patients had higher plasma levels of IL-6, IL-8, and TNF-α compared to HC. In particular, the proliferative response of NKT cells to α-GalCer was significantly decreased in the presence of these cytokines. Such decrease was partially recovered after treatment with blocking antibodies against these cytokines. This study demonstrates that circulating NKT cells are numerically deficient and functionally impaired in IFN-γ production in trauma patients. These findings provide an important insight into the trauma-related innate immune response.

An investigation into the modulation of T cell phenotypes by amitriptyline and nortriptyline

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

S.13.02 Dark microglia: remodelling neuronal circuits in psychiatric disorders

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

P.030 Cognitive impairment and treatment of depression

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

S.18.03 IGF1 and derivatives in the treatment of neurodevelopmental disorders

Amitriptyline is prescribed for treating the symptoms of neuroinflammatory disorders including neuropathic pain and fibromyalgia. As amitriptyline has evidence of modulating the neuroimmune interface; the effects of amitriptyline treatment on T-cell phenotype and function were examined in vitro. Peripheral blood mononuclear cells(PBMCs) were isolated and treated with amitriptyline, nortriptyline and a combination of both drugs. Toxicity for T-cells was assessed by Annexin V/Propidium Iodide staining. Activation status and cytokine expression by T-cells post treatment was assessed by flow cytometry. The levels of secreted cytokines, chemokines and neurotrophins were measured by ELISA in the supernatants. There was no significant increase in T-cell death following 24 or 48 h compared to controls. There were significantly lower frequencies of CD8+ T-cells after treatment with amitriptyline, nortriptyline and a combination of both compared to a Vehicle Control(VC)(p<0.001). The frequencies of naive CD8+CD45RA+ cells were significantly lower after amitriptyline, nortriptyline and a combination of both (p<0001). The frequencies of CD27+CD4+(p<0.05) and CD27+CD8+(p<0.01) T-cells were also significantly lower following combination drug treatment. Significantly lower frequencies of IFN-γ-producing CD8+ T-cells were observed with all treatment combinations(p<0.05) and frequencies of IL-17-producing CD4+ and CD8+ T-cells were significantly lower following amitriptyline treatment (p<0.05). Frequencies of Natural Killer T-cells were significantly higher following treatment with nortriptyline (p<0.05). Significantly higher levels of IL-16 (p<0.001) and lower levels of TNF-β (p<0.05) were observed in supernatants. This data indicates that both amitriptyline and nortriptyline modulate the phenotype and function of T-cells and this may have clinical relevance in the pathologies of its off-label applications.

Regulatory T cells induce CD4- NKT cell anergy and suppress NKT cell cytotoxic function.

Due to the strong tumoricidal activities of activated natural killer T (NKT) cells, invariant NKT cell-based immunotherapy has shown promising clinical efficacy. However, suppressive factors, such as regulatory T cells (Tregs), may be obstacles in the use of NKT cell-based cancer immunotherapy for advanced cancer patients. Here, we investigated the suppressive effects of Tregs on NKT cells and the underlying mechanisms with the aim to improve the antitumor activities of NKT cells. Peripheral blood samples were obtained from healthy donors, patients with benign tumors, and patients with head and neck squamous cell carcinoma (HNSCC). NKT cells, induced with α-galactosylceramide (α-GalCer), and monocyte-derived dendritic cells (DCs) were co-cultured with naïve CD4+ T cell-derived Tregs to investigate the mechanism of the Treg suppressive effect on NKT cell cytotoxic function. The functions and phenotypes of NKT cells were evaluated with flow cytometry and cytometric bead array. Treg suppression on NKT cell function required cell-to-cell contact and was mediated via impaired DC maturation. NKT cells cultured under Treg-enriched conditions showed a decrease in CD4- NKT cell frequency, which exert strong tumoricidal responsiveness upon α-GalCer stimulation. The same results were observed in HNSCC patients with significantly increased effector Tregs. Tregs exert suppressive effects on NKT cell tumoricidal function by inducing more CD4- NKT cell anergy and less CD4+ NKT cell anergy. Both Treg depletion and NKT cell recovery from the anergy state may be important for improving the clinical efficacy of NKT cell-based immunotherapy in patients with advanced cancers.

Natural Killer and Natural Killer T Cells in Juvenile Systemic Lupus Erythematosus: Relation to Disease Activity and Progression.

The contribution of innate immune cells, including natural killer (NK) and natural killer T (NKT) cells, in systemic lupus erythematosus (SLE) is still unclear. Herein, we examined the frequency of peripheral NK cells, CD56dim and CD56bright NK cells, and NKT cells in patients with juvenile SLE and their potential relations to SLE-related clinical and laboratory parameters. The study included 35 SLE children and 20 apparently healthy controls. After baseline clinical and lab work, SLE Disease Activity Index (SLEDAI-2K) and Pediatric Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) Damage Index (Ped-SDI) scores were assessed. The frequency of peripheral NK cells, CD56dim and CD56bright NK cells, and NKT cells was examined using flow cytometry. SLE patients showed significantly lower frequency of NK cells and NKT cells and higher frequency of CD56bright NK cells compared to controls. Disease activity, urea, and creatinine correlated negatively with NK, but positively with CD56bright NK cells. NK and NKT cells exhibited inverse correlation with the renal biopsy activity index; however, CD56bright NK cells showed direct correlations with both activity and chronicity indices. Regarding Ped-SDI, renal, neuropsychiatry disorders, and growth failure correlated inversely with NK but directly with CD56bright NK cells. NKT cell inversely correlated with renal damage and delayed puberty. In conclusion, low frequency of NK and NKT and expansion of CD56bright NK cells are marked in juvenile SLE, particularly with activity. These changes have direct effect on renal impairment and growth failure, reflecting their potential influence on disease progression.

Natural Killer T cells in Egyptian Patients with HCV-associated Non-alcoholic Fatty Liver Disease

Background:Studies on Natural Killer T (NKT) cells in Non-alcoholic fatty liver disease (NAFLD) have shown contradictory results. Moreover, the effect of HCV superinfection on NKT cells in NAFLD patients have not been previously studied. Aim: to assess the effect of the concomitant HCV infection on the frequency of NKT cells and CD8+ T cells in a cohort of Egyptian patients with hepatic steatosis. Subjects and Methods: Two-hundred subjects were divided into four equal groups, 1) concomitant hepatic steatosis/HCV, 2) HCV (without steatosis), 3) steatosis (without HCV), and 4) normal controls. NKT and CD8+ T cells were identified by monoclonal antibodies surface staining for (CD3, CD56, CD161), and (CD3, CD8) respectively using flow cytometry. Results: CD3+/CD56+/CD161+ NKT cells were significantly higher in patients with either steatosis (alone) or concomitant HCV/steatosis compared to control (p<0.0001 each), while comparable NKT frequency was found between HCV group and control (p=0.72). A significant increase in CD3+/CD8+ T cells was noted in the three patients’ groups compared to control (p=0.0001, 0.002 and 0.001, respectively). Interestingly, NKT cells were significantly higher in patients with steatosis/HCV compared to those with HCV alone (p<0.0001), while, they did not differ betweenconcomitant HCV/steatosis and steatosis (alone) group. Higher frequencies of both NKT cells and CD8+ T cells were significantly associated with increased severity of steatosis. In HCV group, NKT frequencies were unrelated to steatosis severity. Conclusion: NKT cells are significantly elevated in patients with hepatic steatosis irrespective to the presence or absence of concomitant HCV infection.

The Role of Invariant NKT in Autoimmune Liver Disease: Can Vitamin D Act as an Immunomodulator?

Natural killer T (NKT) cells are a distinct lineage of T cells which express both the T cell receptor (TCR) and natural killer (NK) cell markers. Invariant NKT (iNKT) cells bear an invariant TCR and recognize a small variety of glycolipid antigens presented by CD1d (nonclassical MHC-I). CD1d-restricted iNKT cells are regulators of immune responses and produce cytokines that may be proinflammatory (such as interferon-gamma (IFN-γ)) or anti-inflammatory (such as IL-4). iNKT cells also appear to play a role in B cell regulation and antibody production. Alpha-galactosylceramide (α-GalCer), a derivative of the marine sponge, is a potent stimulator of iNKT cells and has been proposed as a therapeutic iNKT cell activator. Invariant NKT cells have been implicated in the development and perpetuation of several autoimmune diseases such as multiple sclerosis and systemic lupus erythematosus (SLE). Animal models of SLE have shown abnormalities in iNKT cells numbers and function, and an inverse correlation between the frequency of NKT cells and IgG levels has also been observed. The role of iNKT cells in autoimmune liver disease (AiLD) has not been extensively studied. This review discusses the current data with regard to iNKT cells function in AiLD, in addition to providing an overview of iNKT cells function in other autoimmune conditions and animal models. We also discuss data regarding the immunomodulatory effects of vitamin D on iNKT cells, which may serve as a potential therapeutic target, given that deficiencies in vitamin D have been reported in various autoimmune disorders.

CD70 Modulates Thymocyte Development and Type 1 Diabetes in NOD Mice

CD70 is a tumor necrosis factor (TNF) superfamily member expressed by activated T cells, B cells, dendritic cells, NK cells and mature macrophages. It interacts with CD27, a TNF receptor family member on T cells that regulates T cell activation, proliferation and survival. Type 1 diabetes (T1D) is caused by T cell mediated beta cell destruction, however, T1D-prone NOD mice developed accelerated disease in the absence of CD70. This was associated with altered proportions of double negative vs. double positive thymocytes in CD70 knockout mice, indicating that CD70 modulates global thymopoiesis. Also affected, but in opposing directions, was the development of regulatory T cells (Treg) and natural killer T (NKT) cells, two immunoregulatory lymphocyte subsets that are functionally and numerically deficient in NOD mice. Tregs frequencies were reduced by 23% and 32% in CD70 heterozygous (CD70-/+) and homozygous (CD70-/-) knockout mice. In contrast, NKT cell frequencies were respectively increased by 48% and 61% in CD70-/+ and CD70-/- mice compared to standard NOD mice. The higher level of NKT cells in CD70 knockout mice was unexpectedly associated with reduced levels of thymic CD1d, a molecule that is required for NKT cell development. Collectively, our results show that CD70 controls the development of several T cell populations that are known to modulate T1D development in NOD mice and that, in the absence of CD70, T1D is exacerbated. These finding may facilitate the development of clinical therapeutics aimed at enhancing the stimulatory function of CD70 as a way to suppress disease. Disclosure C. Ye: None. J. Driver: None. M.V. Wiles: None. D. Serreze: None.

CD1d-Restricted Natural Killer T Cells Are Preserved in Indian Long-Term Nonprogressors.

Natural killer T (NKT) cells act as a bridge between innate and adaptive immune responses. Limited information is available regarding the role of NKT cells in the HIV disease progression especially HIV-1 C infection. NKT cells were characterized for their frequency and the activation, aging, exhaustion status, and their proliferation ability in 32 long-term nonprogressors (LTNPs), 40 progressors, 18 patients before and after suppressive combination antiretroviral therapy (cART) along with 35 HIV-1-negative subjects using multicolor flow cytometry. The frequencies of total NKT cells and their subpopulation were significantly higher in LTNPs as compared with those obtained in progressors (P < 0.0001) and were significantly associated with higher CD4 counts and with lower plasma viral loads. The percentage of activated, aged, and exhausted NKT cells were significantly lower in LTNPs as compared with the progressors and inversely correlated with CD4 count and positively with plasma viral loads. The NKT cells from the LTNPs showed higher proliferation ability. The frequency and proliferation ability of the NKT cells were partially restored after 12 months of suppressive cART but still lower than the levels in LTNPs. The degree of restoration after cART was similar in both CD4 and CD4 NKT cells. The findings demonstrate significant association of preserved NKT cells with the nonprogressive HIV infection and also showed that exhausted NKT cells are associated with disease progression. Further characterization of their functionality and assessment of sustenance in HIV infection will help to understand the HIV pathogenesis and to develop immune therapies.

The cytokine profile of human NKT cells and PBMCs is dependent on donor sex and stimulus.

Sex-related variations in natural killer T (NKT) cells may influence immunoregulation and outcome of infectious and autoimmune diseases. We analyzed sex-specific differences in peripheral blood NKTs and peripheral blood mononuclear cells (PBMCs) from men and women and determined the frequencies of NKT cells and their subpopulations [CD4+; CD8+; double negative (DN)] and the levels of cytokine production following stimulation with the NKT cell ligands α-Galactosylceramide (αGalCer) and Entamoeba histolytica lipopeptidephosphoglycan (Lotter et al. in PLoS Pathog 5(5):e1000434, 2009). Total and DN NKT cells were more abundant in women than in men. In women, αGalCer induced higher production of intracellular IFNγ, IL-4, IL-17 and TNF by CD4+ and DN+NKT cells. Both ligands induced expression of multiple cytokines in PBMCs and influenced the ratio of NKT cell subpopulations during long-term culture. Although the sex-specific differences in frequencies of NKT cells and their subpopulations were marginal, the significant sex-specific differences in cytokine production might influence disease outcomes.

Targeted disruption of CD1d prevents NKT cell development in pigs.

Studies in mice genetically lacking natural killer T (NKT) cells show that these lymphocytes make important contributions to both innate and adaptive immune responses. However, the usefulness of murine models to study human NKT cells is limited by the many differences between mice and humans, including that their NKT cell frequencies, subsets, and distribution are dissimilar. A more suitable model may be swine that share many metabolic, physiological, and growth characteristics with humans and are also similar for NKT cells. Thus, we analyzed genetically modified pigs made deficient for CD1d that is required for the development of Type I invariant NKT (iNKT) cells that express a semi-invariant T-cell receptor (TCR) and Type II NKT cells that use variable TCRs. Peripheral blood analyzed by flow cytometry and interferon-γ enzyme-linked immuno spot assays demonstrated that CD1d-knockout pigs completely lack iNKT cells, while other leukocyte populations remain intact. CD1d and NKT cells have been shown to be involved in shaping the composition of the commensal microbiota in mice. Therefore, we also compared the fecal microbiota profile between pigs expressing and lacking NKT cells. However, no differences were found between pigs lacking or expressing CD1d. Our results are the first to show that knocking-out CD1d prevents the development of NKT cells in a non-rodent species. CD1d-deficient pigs should offer a useful model to more accurately determine the contribution of NKT cells for human immune responses. They also have potential for understanding how NKT cells impact the health of commercial swine.

Adjuvant effects of therapeutic glycolipids administered to a cohort of NKT cell-diverse pigs

CD1d-restricted natural killer T (NKT) cells are a unique lymphocyte population that makes important contributions to host defense against numerous microbial pathogens. The powerful immunomodulatory effects of these cells can be exploited in mice by cognate antigens for multiple therapeutic purposes, including for protection from infectious diseases and as adjuvants to improve vaccines against microbial organisms. These applications have potential to treat and prevent infectious diseases in livestock species that express NKT cells, including pigs. In this study, immune tissues from commercial swine of mixed genetic background were compared for NKT cell frequency, cytokine secretion and subset ratios. Pigs were also injected with the model antigen hen-egg lysozyme (HEL) in conjunction with one of three glycosphingolipids, alpha-galactosylceramide (αGC), OCH and C-glycoside that selectively activate NKT cells, to assess the adjuvant potential of each. There was significant variation between individual pigs for all NKT cell parameters measured. The NKT cell agonists elicited HEL-specific immune responses of different quality, but only αGC increased the systemic concentration of NKT cells. Peripheral blood NKT cell frequency measured prior to treatment was a poor predictor of how individual animals responded to NKT cell therapy. However, our results show that although NKT cells vary considerably between pigs, there exists considerable potential to harness these cells to protect swine from infectious diseases.

Hepatic compartmentalization of exhausted and regulatory cells in HIV/HCV-coinfected patients.

Accelerated intrahepatic hepatitis C virus (HCV) pathogenesis is likely the result of dysregulation within both the innate and adaptive immune compartments, but the exact contribution of peripheral blood and liver lymphocyte subsets remains unclear. Prolonged activation and expansion of immunoregulatory cells have been thought to play a role. We determined immune cell subset frequency in contemporaneous liver and peripheral blood samples from chronic HCV-infected and HIV/HCV-coinfected individuals. Peripheral blood mononuclear cells (PBMC) and biopsy-derived liver-infiltrating lymphocytes from 26 HIV/HCV-coinfected, 10 chronic HCV-infected and 10 HIV-infected individuals were assessed for various subsets of T and B lymphocytes, dendritic cell, natural killer (NK) cell and NK T-cell frequency by flow cytometry. CD8(+) T cells expressing the exhaustion marker PD-1 were increased in HCV-infected individuals compared with uninfected individuals (P = 0.02), and HIV coinfection enhanced this effect (P = 0.005). In the liver, regulatory CD4(+) CD25(+) Foxp3(+) T cells, as well as CD4(+) CD25(+) PD1(+) T cells, were more frequent in HIV/HCV-coinfected than in HCV-monoinfected samples (P < 0.001). HCV was associated with increased regulatory T cells, PD-1(+) T cells and decreased memory B cells, regardless of HIV infection (P ≤ 0.005 for all). Low CD8(+) expression was observed only in PD-1(+) CD8(+) T cells from HCV-infected individuals and healthy controls (P = 0.002) and was associated with enhanced expansion of exhausted CD8(+) T cells when exposed in vitro to PHA or CMV peptides. In conclusion, in HIV/HCV coinfection, ongoing HCV replication is associated with increased regulatory and exhausted T cells in the periphery and liver that may impact control of HCV. Simultaneous characterization of liver and peripheral blood highlights the disproportionate intrahepatic compartmentalization of immunoregulatory T cells, which may contribute to establishment of chronicity and hepatic fibrogenesis in HIV coinfection.

Natural killer T cell defects in multiple myeloma and the impact of lenalidomide therapy

The causes of multiple myeloma (MM) remain obscure and there are few known risk factors; however, natural killer T (NKT) cell abnormalities have been reported in patients with MM, and therapeutic targeting of NKT cells is promoted as a potential treatment. We characterized NKT cell defects in treated and untreated patients with MM and determined the impact of lenalidomide therapy on the NKT cell pool. Lenalidomide is an immunomodulatory drug with co-stimulatory effects on NKT cells in vitro and is an approved treatment for MM, although its mode of action in that context is not well defined. We find that patients with relapsed/progressive MM had a marked deficiency in NKT cell numbers. In contrast, newly diagnosed patients had relatively normal NKT cell frequency and function prior to treatment, although a specific NKT cell deficiency emerged after high-dose melphalan and autologous stem cell transplantation (ASCT) regimen. This also impacted NK cells and conventional T cells, but the recovery of NKT cells was considerably delayed, resulting in a prolonged, treatment-induced NKT cell deficit. Longitudinal analysis of individual patients revealed that lenalidomide therapy had no in-vivo impact on NKT cell numbers or cytokine production, either as induction therapy, or as maintenance therapy following ASCT, indicating that its clinical benefits in this setting are independent of NKT cell modulation.