Biological interactions of polystyrene nanoplastics: Their cytotoxic and immunotoxic effects on the hepatic and enteric systems.

As emerging pollutants in the environment, nanoplastics (NPs) can cross biological barriers and be enriched in organisms, posing a greatest threat to the health of livestock and humans. However, the size-dependent toxic effects of NPs in higher mammals remain largely unknown. To determine the size-dependent potential toxicities of NPs, we exposed mouse (AML-12) and human (L02) liver cell lines in vitro, and 6-week-old C57BL/6 mice (well-known preclinical model) in vivo to five different sizes of polystyrene NPs (PS-NPs) (20, 50, 100, 200 and 500 nm). We found that ultra-small NPs (20 nm) induced the highest cytotoxicity in mouse and human liver cell lines, causing oxidative stress and mitochondrial membrane potential loss on AML-12 cells. Unexpectedly in vivo, after long-term oral exposure to PS-NPs (75 mg/kg), medium NPs (200 nm) and large NPs (500 nm) induced significant hepatotoxicity, evidenced by increased oxidative stress, liver dysfunction, and lipid metabolism disorders. Most importantly, medium or large NPs generated local immunotoxic effects via recruiting and activating more numbers of neutrophils and monocytes in the liver or intestine, which potentially resulted in increased proinflammatory cytokine secretion and the tissue damage. The discrepancy in in vitro-in vivo toxic results might be attributed to the different properties of biodistribution and tissue accumulation of different sized NPs in vivo. Our study provides new insights regarding the hepatotoxicity and immunotoxicity of NPs on human and livestock health, warranting us to take immense measures to prevent these NPs-associated health damage.

Nanovaccine-Based Strategies to Overcome Challenges in the Whole Vaccination Cascade for Tumor Immunotherapy.

Nanovaccine-based immunotherapy (NBI) has received greater attention recently for its potential to prime tumor-specific immunity and establish a long-term immune memory that prevents tumor recurrence. Despite encouraging results in the recent studies, there are still numerous challenges to be tackled for eliciting potent antitumor immunity using NBI strategies. Based on the principles that govern immune response, here it is proposed that these challenges need to be addressed at the five critical cascading events: Loading tumor-specific antigens by nanoscale drug delivery systems (L); Draining tumor antigens to lymph nodes (D); Internalization by dendritic cells (DCs) (I); Maturation of DCs by costimulatory signaling (M); and Presenting tumor-peptide-major histocompatibility complexes to T cells (P) (LDIMP cascade in short). This review provides a detailed and objective overview of emerging NBI strategies to improve the efficacy of nanovaccines in each step of the LDIMP cascade. It is concluded that the balance between each step must be optimized by delicate designing and modification of nanovaccines and by combining with complementary approaches to provide a synergistic immunity in the fight against cancer.

Inhibition of MEK-ERK1/2-MAP kinase signalling pathway reduces rabies virus induced pathologies in mouse model.

The extracellular signal-regulated kinase (ERK) pathway has been shown to regulate pathogenesis of many viral infections, but its role during rabies virus (RV) infection in vivo is not clear. In the present study, we investigated the potential role of MEK-ERK1/2 signalling pathway in the pathogenesis of rabies in mouse model and its regulatory effects on pro-inflammatory cytokines and other mediators of immunity, and kinetics of immune cells. Mice were infected with 25 LD50 of challenge virus standard (CVS) strain of RV by intracerebral (i.c.) inoculation and were treated i.c. with U0126 (specific inhibitor of MEK1/2) at 10 µM/mouse at 0, 2, 4 and 6 days post-infection. Treatment with U0126 resulted in delayed disease development and clinical signs, increased survival time with lesser mortality than untreated mice. The better survival of inhibitor-treated and RV infected mice was positively correlated with reduced viral load and reduced viral spread in the brain as quantified by real-time PCR, direct fluorescent antibody test and immunohistochemistry. CVS-infected/mock-treated mice developed severe histopathological lesions with increased Fluoro-Jade B positive degenerating neurons in brain, which were associated with higher levels of serum nitric oxide, iNOS, TNF-α, and CXCL10 mRNA. Also CVS-infected/U0126-treated mice revealed significant decrease in caspase 3 but increase in Bcl-2 mRNA levels and less TUNEL positive apoptotic cells. CVS-infected/U0126-treated group also showed significant increase in CD4+, CD8+ T lymphocytes and NK cells in blood and spleen possibly due to less apoptosis of these cells. In conclusion, these data suggest that MEK-ERK1/2 signalling pathway play critical role in the pathogenesis of RV infection in vivo and opens up new avenues of therapeutics.

Simulated Microgravity Promotes Cell Apoptosis Through Suppressing Uev1A/TICAM/TRAF/NF-κB-Regulated Anti-Apoptosis and p53/PCNA- and ATM/ATR-Chk1/2-Controlled DNA-Damage Response Pathways.

Microgravity has been known to induce cell death. However, its underlying mechanism is less studied. In this study, BL6-10 melanoma cells were cultured in flasks under simulated microgravity (SMG). We examined cell apoptosis, and assessed expression of genes associated with apoptosis and genes regulating apoptosis in cells under SMG. We demonstrate that SMG induces cell morphological changes and microtubule alterations by confocal microscopy, and enhances apoptosis by flow cytometry, which was associated with up- and down-regulation of pro-apoptotic and anti-apoptotic genes, respectively. Moreover, up- and down-regulation of pro-apoptotic (Caspases 3, 7, 8) and anti-apoptotic (Bcl2 and Bnip3) molecules was confirmed by Western blotting analysis. Western blot analysis also indicates that SMG causes inhibition of an apoptosis suppressor, pNF-κB-p65, which is complemented by the predominant localization of NF-κB-p65 in the cytoplasm. SMG also reduces expression of molecules regulating the NF-κB pathway including Uev1A, TICAM, TRAF2, and TRAF6. Interestingly, 10 DNA repair genes are down-regulated in cells exposed to SMG, among which down-regulation of Parp, Ercc8, Rad23, Rad51, and Ku70 was confirmed by Western blotting analysis. In addition, we demonstrate a significant inhibition of molecules involved in the DNA-damage response, such as p53, PCNA, ATM/ATR, and Chk1/2. Taken together, our work reveals that SMG promotes the apoptotic response through a combined modulation of the Uev1A/TICAM/TRAF/NF-κB-regulated apoptosis and the p53/PCNA- and ATM/ATR-Chk1/2-controlled DNA-damage response pathways. Thus, our investigation provides novel information, which may help us to determine the cause of negative alterations in human physiology occurring at spaceflight environment. J. Cell. Biochem. 117: 2138-2148, 2016. © 2016 Wiley Periodicals, Inc.

Re-programming mouse liver-resident invariant natural killer T cells for suppressing hepatic and diabetogenic autoimmunity.

Invariant NKT (iNKT) cells comprise a heterogeneous group of non-circulating, tissue-resident T lymphocytes that recognize glycolipids, including alpha-galactosylceramide (αGalCer), in the context of CD1d, but whether peripheral iNKT cell subsets are terminally differentiated remains unclear. Here we show that mouse and human liver-resident αGalCer/CD1d-binding iNKTs largely correspond to a novel Zbtb16+Tbx21+Gata3+MaflowRorc- subset that exhibits profound transcriptional, phenotypic and functional plasticity. Repetitive in vivo encounters of these liver iNKT (LiNKT) cells with intravenously delivered αGalCer/CD1d-coated nanoparticles (NP) trigger their differentiation into immunoregulatory, IL-10+IL-21-producing Zbtb16highMafhighTbx21+Gata3+Rorc- cells, termed LiNKTR1, expressing a T regulatory type 1 (TR1)-like transcriptional signature. This response is LiNKT-specific, since neither lung nor splenic tissue-resident iNKT cells from αGalCer/CD1d-NP-treated mice produce IL-10 or IL-21. Additionally, these LiNKTR1 cells suppress autoantigen presentation, and recognize CD1d expressed on conventional B cells to induce IL-10+IL-35-producing regulatory B (Breg) cells, leading to the suppression of liver and pancreas autoimmunity. Our results thus suggest that LiNKT cells are plastic for further functional diversification, with such plasticity potentially targetable for suppressing tissue-specific inflammatory phenomena.

CD4+ Th-APC with acquired peptide/MHC class I and II complexes stimulate type 1 helper CD4+ and central memory CD8+ T cell responses.

T cell-T cell Ag presentation is increasingly attracting attention. We previously showed that the in vitro OVA-pulsed dendritic cell (DC(OVA))-activated CD4(+) Th cells acquired OVA peptide/MHC (pMHC) class I and costimulatory molecules such as CD54 and CD80 from DC(OVA) and acted as CD4(+) Th-APC capable of stimulating OVA-specific CD8(+) CTL responses. In this study, we further applied the OVA-specific TCR-transgenic OT I and OT II mice with deficiency of various cytokines or costimulatory molecule genes useful for studying the molecular mechanisms underlying in Th-APC's stimulatory effect. We demonstrated that DC(OVA)-stimulated OT II CD4(+) Th-APC also acquired costimulatory molecules such as CD40, OX40L, and 4-1BBL and the functional pMHC II complexes by DC(OVA) activation. CD4(+) Th-APC with acquired pMHC II and I were capable of stimulating CD4(+) Th1 and central memory CD8(+)44(+)CD62L(high)IL-7R(+) T cell responses leading to antitumor immunity against OVA-expressing mouse B16 melanoma. Their stimulatory effect on CD8(+) CTL responses and antitumor immunity is mediated by IL-2 secretion, CD40L, and CD80 signaling and is specifically targeted to CD8(+) T cells in vivo via acquired pMHC I. In addition, CD4(+) Th-APC expressing OVA-specific TCR, FasL, and perforin were able to kill DC(OVA) and neighboring Th-APC expressing endogenous and acquired pMHC II. Taken together, we show that CD4(+) Th-APC can modulate immune responses by stimulating CD4(+) Th1 and central memory CD8(+) T cell responses and eliminating DC(OVA) and neighboring Th-APC. Therefore, our findings may have great impacts in not only the antitumor immunity, but also the regulatory T cell-dependent immune tolerance in vivo.

Liver-specific T regulatory type-1 cells program local neutrophils to suppress hepatic autoimmunity via CRAMP.

Neutrophils with immunoregulatory properties, also referred to as type-2 neutrophils (N2), myeloid-derived suppressor cells (MDSCs), or tumor-associated neutrophils (TANs), comprise a heterogeneous subset of cells that arise from unknown precursors in response to poorly understood cues. Here, we find that, in several models of liver autoimmunity, pharmacologically induced, autoantigen-specific T regulatory type-1 (TR1) cells and TR1-cell-induced B regulatory (Breg) cells use five immunoregulatory cytokines to coordinately recruit neutrophils into the liver and program their transcriptome to generate regulatory neutrophils. The liver-associated neutrophils from the treated mice, unlike their circulating counterparts or the liver neutrophils of sick mice lacking antigen-specific TR1 cells, are proliferative, can transfer disease protection to immunocompromised hosts engrafted with pathogenic effectors, and blunt antigen-presentation and local autoimmune responses via cathelin-related anti-microbial peptide (CRAMP), a cathelicidin, in a CRAMP-receptor-dependent manner. These results, thus, identify antigen-specific regulatory T cells as drivers of tissue-restricted regulatory neutrophil formation and CRAMP as an effector of regulatory neutrophil-mediated immunoregulation.

A tumor-to-lymph procedure navigated versatile gel system for combinatorial therapy against tumor recurrence and metastasis.

Application of cancer vaccines is limited due to their systemic immunotoxicity and inability to satisfy all the steps, including loading of tumor antigens, draining of antigens to lymph nodes (LNs), internalization of antigens by dendritic cells (DCs), DC maturation, and cross-presentation of antigens for T cell activation. Here, we present a combinatorial therapy, based on a α-cyclodextrin (CD)-based gel system, DOX/ICG/CpG-P-ss-M/CD, fabricated by encapsulating doxorubicin (DOX) and the photothermal agent indocyanine green (ICG). Upon irradiation, the gel system exhibited heat-responsive release of DOX and vaccine-like nanoparticles, CpG-P-ss-M, along with chemotherapy- and phototherapy-generated abundant tumor-specific antigen storage in situ. The released CpG-P-ss-M acted as a carrier adsorbed and delivered antigens to LNs, promoting the uptake of antigens by DCs and DC maturation. Notably, combined with PD-L1 blocking, the therapy effectively inhibited primary tumor growth and induced tumor-specific immune response against tumor recurrence and metastasis.

Ubiquitous antigen-specific T regulatory type 1 cells variably suppress hepatic and extrahepatic autoimmunity.

Peptide MHC class II-based (pMHCII-based) nanomedicines trigger the formation of multicellular regulatory networks by reprogramming autoantigen-experienced CD4+ T cells into autoimmune disease-suppressing T regulatory type 1 (TR1) cells. We have shown that pMHCII-based nanomedicines displaying liver autoimmune disease-relevant yet ubiquitously expressed antigens can blunt various liver autoimmune disorders in a non-disease-specific manner without suppressing local or systemic immunity against infectious agents or cancer. Here, we show that such ubiquitous autoantigen-specific T cells are also awakened by extrahepatic tissue damage and that the corresponding TR1 progeny can suppress experimental autoimmune encephalomyelitis (EAE) and pancreatic ß cell autoreactivity. In mice having EAE, nanomedicines displaying either ubiquitous or CNS-specific epitopes triggered the formation and expansion of cognate TR1 cells and their recruitment to the CNS-draining lymph nodes, sparing their liver-draining counterparts. Surprisingly, in mice having both liver autoimmunity and EAE, liver inflammation sequestered these ubiquitous or even CNS-specific TR1 cells away from the CNS, abrogating their antiencephalitogenic activity. In these mice, only the ubiquitous antigen-specific TR1 cells suppressed liver autoimmunity. Thus, the scope of antigen spreading in autoimmune disorders is larger than previously anticipated, involving specificities expected to be silenced by mechanisms of tolerance; the regulatory activity, but not the retention of autoreactive TR1 cells, requires local autoantigen expression.

Phagocyte-membrane-coated and laser-responsive nanoparticles control primary and metastatic cancer by inducing anti-tumor immunity.

To achieve safe and effective antitumor immunity, we constructed the M1-macrophage-membrane-coated nanoparticles [(C/I)BP@B-A(D)&M1m] having laser-responsive, size-changeable, on-demand drug release and prolonged circulation retention properties. (C/I)BP@B-A(D)&M1m delayed clearance by the phagocytic system and homed to tumor efficiently. Upon 650 nm laser irradiation, the hydrophobic core of the PEGylated bilirubin nanoparticles (BP) got disrupted, releasing small-sized deep-penetrating B-A(D) particles, photosensitive chlorin e6 (C), and tolerance-inducing indoleamine 2,3-dioxygenase inhibitor, indoximode (I). Treatment-induced immunogenic cell death and antitumor immunity, suppressing primary tumor growth in both 4T1 and B16F10 models without causing any adverse effects. Most importantly, it inhibited primary tumor recurrence as well as metastasis. Thus, this study provides a promising combinatorial strategy to trigger antitumor immunity in malignancies.

Suppression of a broad spectrum of liver autoimmune pathologies by single peptide-MHC-based nanomedicines.

Peptide-major histocompatibility complex class II (pMHCII)-based nanomedicines displaying tissue-specific autoantigenic epitopes can blunt specific autoimmune conditions by re-programming cognate antigen-experienced CD4+ T-cells into disease-suppressing T-regulatory type 1 (TR1) cells. Here, we show that single pMHCII-based nanomedicines displaying epitopes from mitochondrial, endoplasmic reticulum or cytoplasmic antigens associated with primary biliary cholangitis (PBC) or autoimmune hepatitis (AIH) can broadly blunt PBC, AIH and Primary Sclerosing Cholangitis in various murine models in an organ- rather than disease-specific manner, without suppressing general or local immunity against infection or metastatic tumors. Therapeutic activity is associated with cognate TR1 cell formation and expansion, TR1 cell recruitment to the liver and draining lymph nodes, local B-regulatory cell formation and profound suppression of the pro-inflammatory capacity of liver and liver-proximal myeloid dendritic cells and Kupffer cells. Thus, autoreactivity against liver-enriched autoantigens in liver autoimmunity is not disease-specific and can be harnessed to treat various liver autoimmune diseases broadly.

Comment on "Coadministration of iRGD with Multistage Responsive Nanoparticles Enhanced Tumor Targeting and Penetration Abilities for Breast Cancer Therapy".

Nanomedicine is at the forefront of targeted drug delivery for cancer therapy. An improved combinatorial approach is highlighted for breast cancer treatment by Hu et al. in this issue of ACS Applied Materials and Interfaces. The authors demonstrated that, by combining multistage-responsive nanoparticles carrying a therapeutic drug, doxorubicin, a photothermal agent, indocyanine green, and a nitric oxide donor with photothermal therapy and intravenous injection of a tumor-homing iRGD peptide, one could achieve efficient therapeutics distribution deep inside the tumor and nearly eradicate primary tumor growth. An in-depth understanding of this approach in combination with other strategies such as the use of immunomodulators would facilitate treating metastasis  in distant organs, and clinical translation of this platform, benefiting cancer patients by providing long-lasting efficacy.

Peptide-MHC-based nanomedicines for autoimmunity function as T-cell receptor microclustering devices.

We have shown that nanoparticles (NPs) can be used as ligand-multimerization platforms to activate specific cellular receptors in vivo. Nanoparticles coated with autoimmune disease-relevant peptide-major histocompatibility complexes (pMHC) blunted autoimmune responses by triggering the differentiation and expansion of antigen-specific regulatory T cells in vivo. Here, we define the engineering principles impacting biological activity, detail a synthesis process yielding safe and stable compounds, and visualize how these nanomedicines interact with cognate T cells. We find that the triggering properties of pMHC-NPs are a function of pMHC intermolecular distance and involve the sustained assembly of large antigen receptor microclusters on murine and human cognate T cells. These compounds show no off-target toxicity in zebrafish embryos, do not cause haematological, biochemical or histological abnormalities, and are rapidly captured by phagocytes or processed by the hepatobiliary system. This work lays the groundwork for the design of ligand-based NP formulations to re-program in vivo cellular responses using nanotechnology.

Innate and adoptive immune cells contribute to natural resistance to systemic metastasis of B16 melanoma.

The greatest hurdle in cancer treatment is the metastasis of primary tumors to distant organs. Our knowledge on how different immune cells, in the absence of exogenous stimulation, prevent tumor metastasis in distant organs is poorly understood. Using a highly metastatic murine lung B16 melanoma cell line BL6-10, we employed naive mice that genetically lack CD4(+) or CD8(+) T cells, or are depleted of dendritic cells (DCs) or natural killer (NK) cells to understand the relative importance of these cells in metastasis prevention. Irrespective of the presence of naïve CD4(+) T, CD8(+) T, DCs, or NK cells, lungs, which act as primary site of predilection for B16 melanoma, readily developed numerous lung BL6-10 melanoma colonies. However, their absence led to B16 melanoma metastasis in variable proportions to distant organs, particularly livers, kidneys, adrenals, ovaries, and hearts. NK cells mediate prevention of BL6-10 metastasis to various organs, especially to livers. Mechanistically, CD40L signaling, a critical factor required for DC licensing and CD8(+) cytotoxic T lymphocyte (CTL) responses, was required for CD4(+) T cell-mediated prevention of systemic BL6-10 metastasis. These results suggest that the composition and functions of different immune cells in distant tissue microenvironments (distant organs other than primary sites of predilection) robustly mediate natural resistance against melanoma metastasis. Thus, harnessing these immune cells' responses in immunotherapeutics would considerably limit organ metastasis.

Th cells promote CTL survival and memory via acquired pMHC-I and endogenous IL-2 and CD40L signaling and by modulating apoptosis-controlling pathways.

Involvement of CD4(+) helper T (Th) cells is crucial for CD8(+) cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4(+) Th's signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4(+) Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4(+) T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2K(b)/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4(+) Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4(+) Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4(+) Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.

Novel CD8+ T cell-based vaccine stimulates Gp120-specific CTL responses leading to therapeutic and long-term immunity in transgenic HLA-A2 mice.

The limitations of highly active anti-retroviral therapy have necessitated the development of alternative therapeutics for human immunodeficiency virus type-1 (HIV-1)-infected patients with dysfunctional dendritic cells (DCs) and CD4(+) T cell deficiency. We previously demonstrated that HIV-1 Gp120-specific T cell-based Gp120-Texo vaccine by using ConA-stimulated C57BL/6 (B6) mouse CD8(+) T (ConA-T) cells with uptake of pcDNA(Gp120)-transfected B6 mouse DC line DC2.4 (DC2.4(Gp120))-released exosomes (EXO(Gp120)) was capable of stimulating DC and CD4(+) T cell-independent CD8(+) cytotoxic T lymphocyte (CTL) responses detected in wild-type B6 mice using non-specific PE-anti-CD44 and anti-IFN-γ antibody staining by flow cytometry. To assess effectiveness of Gp120-Texo vaccine in transgenic (Tg) HLA-A2 mice mimicking the human situation, we constructed adenoviral vector AdV(Gp120) expressing HIV-1 GP120 by recombinant DNA technology, and generated Gp120-Texo vaccine by using Tg HLA-A2 mouse CD8(+) ConA-T cells with uptake of AdV(Gp120)-transfected HLA-A2 mouse bone marrow DC (DC(Gp120))-released EXO(Gp120). We then performed animal studies to assess Gp120-Texo-induced stimulation of Gp120-specific CTL responses and antitumor immunity in Tg HLA-A2 mice. We demonstrate that Gp120-Texo vaccine stimulates Gp120-specific CTL responses detected in Tg HLA-A2 mice using Gp120-specific PE-HLA-A2/Gp120 peptide (KLTPLCVTL) tetramer staining by flow cytometry. These Gp120-specific CTLs are capable of further differentiating into functional effectors with killing activity to Gp120 peptide-pulsed splenocytes in vivo. In addition, Gp120-Texo vaccine also induces Gp120-specific preventive, therapeutic (for 6 day tumor lung metastasis) and CD4(+) T cell-independent long-term immunity against B16 melanoma BL6-10(Gp120/A2Kb) expressing both Gp120 and A2Kb (α1 and α2 domains of HLA-A2 and α3 domain of H-2K(b)) in Tg HLA-A2 mice. Taken together, the novel CD8(+) Gp120-Texo vaccine capable of stimulating efficient CD4(+) T cell-independent Gp120-specific CD8(+) CTL responses leading to therapeutic and long-term immunity in Tg HLA-A2 mice may represent a new immunotherapeutic vaccine for treatment of HIV-1 patients with CD4(+) T cell deficiency.

Bluetongue virus - 23 stimulates inducible nitric oxide synthase expression and nitric oxide production in mononuclear cells of blood and/or regional lymphoid organs.

Mononuclear leukocytes of peripheral blood mononuclear cells (PBMCs) and regional lymphoid organs (RLOs) play a critical role in primary BTV replication and subsequent viral dissemination to distant systemic organs. The lesions in animals develop primarily as a result of vascular insult, presumably induced by the activity of viral and/or proinflammatory vasoactive mediators. Hence, the current study was designed in sheep to investigate the responses of potent vasoactivators, inducible nitric oxide synthase (iNOS) and/or nitric oxide (NO) in mononuclear leukocytes of PBMCs and RLOs. The results show that BTV infection of sheep led to enhanced transcription of iNOS in PBMCs and in particular RLOs. The BTV RNAs and/or antigens were readily demonstrable in these mononuclear leukocytes, suggesting the possible role of BTV in iNOS induction. Moreover, upon in vitro infection of PBMCs with BTV-23, iNOS was up-regulated in time-dependent fashion and correlated with increased NO production. The results from these in vivo and in vitro studies thus suggest iNOS and NO produced by mononuclear leukocytes may potentially contribute to vascular-related pathology of BT.

The measurement of three cytokine transcripts in naïve and sensitized ovine peripheral blood mononuclear cells following in vitro stimulation with bluetongue virus serotype-23.

Bluetongue (BT), a serious disease of sheep and some wild ruminants, is caused by bluetongue virus (BTV), a member of the family, Reoviridae. The current research thrust for controlling BT is on development of efficient vaccines, necessitating clear understanding of ovine immunology. At present, comparative studies on cytokine gene expression profiles of naïve and BTV-sensitized peripheral blood mononuclear cells (PBMC) in sheep have not been clearly understood. In the present study, PBMC from naïve and BEI-inactivated-saponin-adjuvanted BTV-1 vaccinated sheep were stimulated in vitro with heterologous BTV-23. At various intervals, RT-qPCR was carried out to estimate cytokine (interferon-gamma, interleukin-12 and interleukin-2) mRNA expressions that are linked to cell-mediated immunity. The results showed that PBMC cytokine profiles were relatively increased both temporally and quantitatively in immunized sheep PBMC compared to naïve ones, suggesting that BTV-1 vaccination may prime immune system that can cross-react with BTV-23 antigens.