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Background: Zinc oxide nanoparticle (ZNP) has been applied in various biomedical fields. Here, we investigated the usage of ZNP as an antigen carrier for vaccine development by combining a high affinity peptide to ZNP. Results: A novel zinc oxide-binding peptide (ZBP), FPYPGGDA, with high affinity to ZNP (Ka = 2.26 × 106 M-1) was isolated from a random peptide library and fused with a bacterial antigen, ScaA of Orientia tsutsugamushi, the causative agent of scrub typhus. The ZNP/ZBP-ScaA complex was efficiently phagocytosed by a dendritic cell line, DC2.4, in vitro and significantly enhanced anti-ScaA antibody responses in vivo compared to control groups. In addition, immunization with the ZNP/ZBP-ScaA complex promoted the generation of IFN-γ-secreting T cells in an antigendependent manner. Finally, we observed that ZNP/ZBP-ScaA immunization provided protective immunity against lethal challenge of O. tsutsugamushi, indicating that ZNP can be used as a potent adjuvant when complexed with ZBP-conjugated antigen. Conclusions: ZNPs possess good adjuvant potential as a vaccine carrier when combined with an antigen having a high affinity to ZNP. When complexed with ZBP-ScaA antigen, ZNPs could induce strong antibody responses as well as protective immunity against lethal challenges of O. tsutsugamushi. Therefore, application of ZNPs combined with a specific soluble antigen could be a promising strategy as a novel vaccine carrier system. [ABSTRACT FROM AUTHOR]

In T cells, the Tec kinases IL-2-inducible T cell kinase (ITK) and resting lymphocyte kinase (RLK) are activated by TCR stimulation and are required for optimal downstream signaling. Studies of CD4+ T cells from Itk-/- and Itk-/-Rlk-/- mice have indicated differential roles of ITK and RLK in Th1, Th2, and Th17 differentiation and cytokine production. However, these findings are confounded by the complex T cell developmental defects in these mice. In this study, we examine the consequences of ITK and RLK inhibition using a highly selective and potent small molecule covalent inhibitor PRN694. In vitro Th polarization experiments indicate that PRN694 is a potent inhibitor of Th1 and Th17 differentiation and cytokine production. Using a T cell adoptive transfer model of colitis, we find that in vivo administration of PRN694 markedly reduces disease progression, T cell infiltration into the intestinal lamina propria, and IFN-γ production by colitogenic CD4+ T cells. Consistent with these findings, Th1 and Th17 cells differentiated in the presence of PRN694 show reduced P-selectin binding and impaired migration to CXCL11 and CCL20, respectively. Taken together, these data indicate that ITK plus RLK inhibition may have therapeutic potential in Th1-mediated inflammatory diseases. [ABSTRACT FROM AUTHOR]

Virus-specific CD8+ T cells in the lymphoid organs contract at the resolution of virus infections by apoptosis or by dissemination into peripheral tissues, and those residing in nonlymphoid organs, including the peritoneal cavity and fat pads, are more resistant to apoptosis than those in the spleen and lymph nodes. This stability of memory T cells in the nonlymphoid tissues may enhance protection to secondary challenges. Here, we show that lymphocytic choriomeningitis virus (LCMV)-specific CD8+ T cells in nonlymphoid tissues were enriched for memory precursors (expressing high levels of interleukin-7 receptor and low levels of killer cell lectin-like receptor G1 [IL-7Rhi KLRG1lo]) and had higher expression of CD27, CXCR3, and T cell factor-1 (TCF- 1), each a marker that is individually correlated with decreased apoptosis. CD+ T cells in the peritoneal cavity of TCF-1-deficient mice had decreased survival, suggesting a role for TCF-1 in promoting survival in the nonlymphoid tissues. CXCR3+ CD8+ T cells resisted apoptosis and accumulated in the lymph nodes of mice treated with FTY720, which blocks the export of lymph node cells into peripheral tissue. The peritoneal exudate cells (PEC) expressed increased amounts of CXCR3 ligands, CXCL9 and CXCL10, which may normally recruit these nonapoptotic cells from the lymph nodes. In addition, adoptive transfer of splenic CD+ T cells into PEC or spleen environments showed that the peritoneal environment promoted survival of CD8+ T cells. Thus, intrinsic stability of T cells which are present in the nonlymphoid tissues along with preferential migration of apoptosisresistant CD8+ T cells into peripheral sites and the availability of tissue-specific factors that enhance memory cell survival may collectively account for the tissue-dependent apoptotic differences. [ABSTRACT FROM AUTHOR]

Notch1 specifically upregulates expression of the cytokine interferon-γ in peripheral T cells through activation of NF-κB. However, how Notch mediates NF-κB activation remains unclear. Here, we examined the temporal relationship between Notch signaling and NF-κB induction during T-cell activation. NF-κB activation occurs within minutes of T-cell receptor (TCR) engagement and this activation is sustained for at least 48 h following TCR signaling. We used γ-secretase inhibitor (GSI) to prevent the cleavage and subsequent activation of Notch family members. We demonstrate that GSI blocked the later, sustained NF-κB activation, but did not affect the initial activation of NF-κB. Using biochemical approaches, as well as confocal microscopy, we show that the intracellular domain of Notch1 (N1IC) directly interacts with NF-κB and competes with IκBα, leading to retention of NF-κB in the nucleus. Additionally, we show that N1IC can directly regulate IFN-γ expression through complexes formed on the IFN-γ promoter. Taken together, these data suggest that there are two ‘waves’ of NF-κB activation: an initial, Notch-independent phase, and a later, sustained activation of NF-κB, which is Notch dependent. [ABSTRACT FROM AUTHOR]

Trained immunity is the long-term functional reprogramming of innate immune cells, which results in altered responses toward a secondary challenge. Despite indoxyl sulfate (IS) being a potent stimulus associated with chronic kidney disease (CKD)-related inflammation, its impact on trained immunity has not been explored. Here, we demonstrate that IS induces trained immunity in monocytes via epigenetic and metabolic reprogramming, resulting in augmented cytokine production. Mechanistically, the aryl hydrocarbon receptor (AhR) contributes to IS-trained immunity by enhancing the expression of arachidonic acid (AA) metabolism-related genes such as arachidonate 5-lipoxygenase (ALOX5) and ALOX5 activating protein (ALOX5AP). Inhibition of AhR during IS training suppresses the induction of IS-trained immunity. Monocytes from end-stage renal disease (ESRD) patients have increased ALOX5 expression and after 6 days training, they exhibit enhanced TNF-α and IL-6 production to lipopolysaccharide (LPS). Furthermore, healthy control-derived monocytes trained with uremic sera from ESRD patients exhibit increased production of TNF-α and IL-6. Consistently, IS-trained mice and their splenic myeloid cells had increased production of TNF-α after in vivo and ex vivo LPS stimulation compared to that of control mice. These results provide insight into the role of IS in the induction of trained immunity, which is critical during inflammatory immune responses in CKD patients. [ABSTRACT FROM AUTHOR]

Recently identified human FOXP3lowCD45RA- inflammatory non-suppressive (INS) cells produce proinflammatory cytokines, exhibit reduced suppressiveness, and promote antitumor immunity unlike conventional regulatory T cells (Tregs). In spite of their implication in tumors, the mechanism for generation of FOXP3lowCD45RA- INS cells in vivo is unclear. We showed that the FOXP3lowCD45RA- cells in human tumors demonstrate attenuated expression of CRIF1, a vital mitochondrial regulator. Mice with CRIF1 deficiency in Tregs bore Foxp3lowINS-Tregs with mitochondrial dysfunction and metabolic reprograming. The enhanced glutaminolysis activated α-ketoglutarate-mTORC1 axis, which promoted proinflammatory cytokine expression by inducing EOMES and SATB1 expression. Moreover, chromatin openness of the regulatory regions of the Ifng and Il4 genes was increased, which facilitated EOMES/SATB1 binding. The increased α-ketoglutarate-derived 2-hydroxyglutarate down-regulated Foxp3 expression by methylating the Foxp3 gene regulatory regions. Furthermore, CRIF1 deficiency-induced Foxp3lowINS-Tregs suppressed tumor growth in an IFN-γ-dependent manner. Thus, CRIF1 deficiency-mediated mitochondrial dysfunction results in the induction of Foxp3lowINS-Tregs including FOXP3lowCD45RA- cells that promote antitumor immunity. [ABSTRACT FROM AUTHOR]

Effector memory (EM) CD8+ T cells expressing lower levels of IL-7R a (IL-7Ralow) from healthy individuals are partly compromised in vitro, but the identity of these cells has remained unclear. In this study, we demonstrate that human IL-7Ralow EM CD8+ T cells are naturally occurring anergic cells in vivo and impaired in proliferation and IL-2 production but competent in IFN-g and TNF-a production, a state that can be restored by IL-2 stimulation. IL-7Ralow EM CD8+ T cells show decreased expression of GATA3 and c-MYC and are defective in metabolic reprogramming toward glycolysis, a process required for the proliferation of T cells. However, IL-7Ralow EM CD8+ T cells can proliferate with TCR stimulation in the presence of IL-2 and IL-15, suggesting that these cells can be restored to normality or increased activity by inflammatory conditions and may serve as a reservoir for functional immunity. [ABSTRACT FROM AUTHOR]

The antioxidant activity and chlorogenic acid and caffeic acid contents were investigated from different parts of Acanthopanax senticosus and A. koreanum. Antioxidant activity was assessed by various in vitro assays such as DPPH, ABTS, FRAP, reducing power assays and ORAC, and the chlorogenic acid and caffeic acid were validated by HPLC chromatography. Among the various extracts, the fruit extracts of A. senticosus and A. koreanum exhibited strongest antioxidant activities including ABTS, FRAP, reducing power and ORAC, however, strongest DPPH radical scavenging activity was observed from the leaf extract of A. senticosus. In addition, the antioxidant activities of various extracts were correlated with total phenolic and proanthocyanidin contents. The major phenolic contents from various parts of these plants observed that leaf extract of A. senticosus expressed higher levels of chlorogenic acid (14.86 mg/dry weigh g) and caffeic acid (3.09 mg/dry weigh g) than other parts. Therefore, these results suggest that the leaf of A. senticosus may be an excellent natural source for functional foods and pharmaceutical agents, and the validated method was useful for the quality control of A. senticosus. [ABSTRACT FROM AUTHOR]