Self-regulated learning profiles including test anxiety linked to stress and performance: A latent profile analysis based across multiple cohorts.

INTRODUCTION: Medical educators aim to understand why students differ in performance and stress. While performance and stress are associated with student demographics, school factors and aspects of self-regulated learning (SRL), it remains unclear how these elements interact within individuals. This multi-cohort study identified SRL profiles among medical students and explored their associations with performance and stress. Additionally, we examined the identified profiles' associations with gender, migration status and assessment policy. METHODS: We used latent profile analysis (LPA) to identify profiles on Motivated Strategies for Learning Questionnaire (MSLQ) scores of six cohorts (2014-2019) of Year 1, first semester medical students (n = 1894) in a Dutch medical school. We used nine MSLQ subscales that measure test anxiety (TA), self-efficacy, deep learning, resource management and value. The university's assessment policy varied, demanding students to obtain 100% or 75% of Year 1 credits to remain enrolled. We defined optimal performance as obtaining all credits at the end of Year 1. Two cohorts completed the Perceived Stress Scale (PSS-14, n = 409) in the 2nd semester. RESULTS: We identified three distinct student profiles: 693/1894(36.6%) were classified as TAhighSRLhigh, 661/1894(34.9%) as TAlowSRLhigh and 540/1894(28.5%) as TAmoderateSRLlow. Females were more likely to belong to TAhighSRLhigh profiles compared to males (effect size [ES] Cramer's V = .13, small). Migration background was not associated with these profiles. The TAhighSRLhigh profile was more prevalent under the 100% assessment policy (ES Cramer's V = .10, negligible). TAlowSRLhigh students demonstrated lower stress levels (PSS = 23.9 out of 56) compared to TAhighSRLhigh students (PSS = 28.7, ES Cohen's d = .62, medium) and TAmoderateSRLlow students (PSS = 28.2, ES Cohen's d = .51, medium). Performance differed among the three profiles (ES Cramer's V = .16, small): 82.5% optimal performance in the TAlowSRLhigh, 71.9% in the TAhighSRLhigh and 65.2% in the TAmoderateSRLlow profile. DISCUSSION: Three distinct SRL student profiles associated with gender, academic performance and perceived stress were identified. Test anxiety had additional value in distinguishing subgroups with differential academic performance and stress. These profiles may aid educators to inform personalised support strategies for novice learners.

The association between how medical students were selected and their perceived stress levels in Year-1 of medical school.

BACKGROUND: The prevalence of medical students' mental distress is high. While schools apply various methods to select a well-performing and diverse student population, little is known about the association between different selection methods and the well-being of these students during medical school. The present retrospective multi-cohort study assessed whether students selected by high grades, assessment, or weighted lottery showed different stress perception levels in Year-1 of medical school. METHODS: Of 1144 Dutch Year-1 medical students, 650 (57%) of the cohorts 2013, 2014, and 2018 who were selected by high grades, assessment, or weighted lottery completed a stress perception questionnaire (PSS-14). A multilevel regression analysis assessed the association between selection method (independent variable) and stress perception levels (dependent variable) while controlling for gender and cohort. In a post-hoc analysis, academic performance (optimal vs. non-optimal) was included in the multilevel model. RESULTS: Students selected by assessment (B = 2.25, p < .01, effect size (ES) = small) or weighted lottery (B = 3.95, p < .01, ES = medium) had higher stress perception levels than students selected by high grades. Extending the regression model with optimal academic performance (B=-4.38, p < .001, ES = medium), eliminated the statistically significant difference in stress perception between assessment and high grades and reduced the difference between weighted lottery and high grades from 3.95 to 2.45 (B = 2.45, p < .05, ES = small). CONCLUSIONS: Selection methods intended to create a diverse student population - assessment and lottery - are associated with higher stress perception levels in Year-1 of medical school. These findings offer medical schools insights into fulfilling their responsibility to take care of their students' well-being.

Discovery and Selection of Hepatitis B Virus-Derived T Cell Epitopes for Global Immunotherapy Based on Viral Indispensability, Conservation, and HLA-Binding Strength.

Immunotherapy represents an attractive option for the treatment of chronic hepatitis B virus (HBV) infection. The HBV proteins polymerase (Pol) and HBx are of special interest for antigen-specific immunotherapy because they are essential for viral replication and have been associated with viral control (Pol) or are still expressed upon viral DNA integration (HBx). Here, we scored all currently described HBx- and Pol-derived epitope sequences for viral indispensability and conservation across all HBV genotypes. This yielded 7 HBx-derived and 26 Pol-derived reported epitopes with functional association and high conservation. We subsequently predicted novel HLA-binding peptides for 6 HLA supertypes prevalent in HBV-infected patients. Potential epitopes expected to be the least prone to immune escape were subjected to a state-of-the-art in vitro assay to validate their HLA-binding capacity. Using this method, a total of 13 HLA binders derived from HBx and 33 binders from Pol were identified across HLA types. Subsequently, we demonstrated interferon gamma (IFN-γ) production in response to 5 of the novel HBx-derived binders and 17 of the novel Pol-derived binders. In addition, we validated several infrequently described epitopes. Collectively, these results specify a set of highly potent T cell epitopes that represent a valuable resource for future HBV immunotherapy design.IMPORTANCE Multiple HBV-derived T cell epitopes have been reported, which can be useful in a therapeutic vaccination strategy. However, these epitopes are largely restricted to HLA-A*02, which is not dominantly expressed in populations with high HBV prevalence. Thus, current epitopes are falling short in the development of a global immunotherapeutic approach. Therefore, we aimed to identify novel epitopes for 6 HLA supertypes most prevalent in the infected population. Moreover, established epitopes might not all be equally effective as they can be subject to different levels of immune escape. It is therefore important to identify targets that are crucial in viral replication and conserved in the majority of the infected population. Here, we applied a stringent selection procedure to compose a combined overview of existing and novel HBV-derived T cell epitopes most promising for viral eradication. This set of T cell epitopes now lays the basis for the development of globally effective HBV antigen-specific immunotherapies.

Effects of raising the bar on medical student study progress: An intersectional approach.

CONTEXT: Medical schools seek for measures to improve their students' study progress and are responsible for a diverse student population. OBJECTIVES: The effect of a stricter academic dismissal (AD) policy in medical school on short-term and long-term study progress was investigated in a longitudinal cohort study. In addition, differential effects for subgroups were assessed by intersecting gender, ethnicity and prior education (intersectional framework). METHODS: Participants were first-year Bachelor students enrolled in 2011 to 2016 in a Dutch medical school. For cohorts 2011-2013, the AD policy consisted of a minimum of 67% of Year-1 credits required to remain enrolled (67%-policy, n = 1189), and for cohorts 2014-2016, this bar was raised to 100% of Year-1 credits (100%-policy, n = 1233). Outcome measures on study progress were Year-1 completion and dropout (short term) and Bachelor completion in three and four years (long term). RESULTS: Overall, Year-1 completion rates increased under the 100%-policy compared to the 67%-policy (OR = 2.50, 95%-CI:2.06-3.03, P < .001). Yet, this increase was not present for students with non-standard prior education - except for males with a migration background (OR = 7.19, 95%-CI:2.33-25.73, P < .01). The dropout rate doubled under the 100%-policy (OR = 2.41, 95%-CI:1.68-3.53, P < .001). Mainly students with standard prior education dropped out more often (OR = 3.68, 95%-CI:2.37-5.89, P < .001), except for males with a migration background. Bachelor completion rates after three and four years were not positively affected by the 100%-policy. Notably, females without a migration background and with non-standard prior education suffered from the 100%-policy regarding Bachelor completion after three years (OR = 0.29, 95%-CI:0.11-0.76, P < .05). CONCLUSIONS: Despite increased dropout rates, the stricter AD policy improved Year-1 completion rates - especially for under-represented subgroups, thereby improving study progress without harming student diversity on the short term. However, these positive effects did not hold regarding Bachelor completion rates indicating that long-term effects require higher performance standards throughout the Bachelor, which in turn may harm other subgroups and thereby student diversity.

Gender-specific effects of raising Year-1 standards on medical students' academic performance and stress levels.

CONTEXT: Medical schools are challenged to create academic environments that stimulate students to improve their study progress without compromising their well-being. OBJECTIVES: This prospective comparative cohort study investigated the effects of raising Year-1 standards on academic performance and on students' chronic psychological and biological stress levels. METHODS: In a Dutch medical school, students within the last Bachelor's degree cohort (n = 410) exposed to the 40/60 (67%) credit Year-1 standard (67%-credit cohort) were compared with students within the first cohort (n = 413) exposed to a 60/60 (100%) credit standard (100%-credit cohort). Main outcome measures were Year-1 pass rate (academic performance), mean score on the Perceived Stress Scale (PSS, psychological stress) and hair cortisol concentration (HCC, biological stress). RESULTS: Year-1 pass rates were significantly higher in the 100%-credit cohort (odds ratio [OR] 4.65). Interestingly, there was a significant interaction effect (OR 0.46), indicating that raising the standard was more effective for male than for female students. PSS scores (n = 234 [response rate [RR]: 57%] and n = 244 [RR: 59%] in the 67%- and 100%-credit cohorts, respectively) were also significantly higher in the 100%-credit cohort (F(1,474)  = 15.08, P < .001). This applied specifically to female students in the 100%-credit cohort. Levels of HCC (n = 181 [RR: 44%] and n = 162 [RR: 39%] respectively) did not differ between cohorts, but were significantly higher in female students (F(1,332)  = 7.93, P < .01). In separate models including cohort and gender, both PSS score (OR 0.91) and HCC (OR 0.38) were significantly associated with Year-1 performance. Only students with both high PSS scores and high HCC values were significantly at risk of lower Year-1 pass rates (OR 0.27), particularly male students. CONCLUSIONS: Raising the Year-1 performance standard increased academic performance, most notably in male students. However, it also increased levels of perceived stress, especially in female students. In particular, the combination of high levels of perceived stress and biological stress, as measured by long-term cortisol, was related to poor academic performance. The study suggests a relationship between raising performance standards and student well-being, with differential effects in male and female students.

Elevated serum levels of soluble CD14 in HBeAg-positive chronic HBV patients upon Peginterferon treatment are associated with treatment response.

Pegylated IFNα (PEG-IFN) is one of the treatment options for chronic HBV (CHB) patients. However, the high patient treatment burden and limited response rate together clearly ask for biomarkers to predict PEG-IFN response. Soluble CD14 (sCD14) is considered a marker for immune activation and has been shown to predict clinical outcome of HIV infection. However, studies on sCD14 in CHB infection are inconclusive, and its relationship with clinical outcome is largely unknown. Here, we measured sCD14 levels in CHB patients and investigated whether changes in sCD14 level related to PEG-IFN response. Serum sCD14 levels were determined in 15 healthy controls, 15 acute self-limited HBV, 60 CHB patients in different disease phases and 94 HBeAg+ CHB patients at week 0 and week 12 of a 52-week PEG-IFN treatment. Response to PEG-IFN treatment was defined as HBeAg seroconversion or HBeAg loss at 26 weeks post-treatment. The mean sCD14 level in acute HBV patients (3.0 µg/mL) was significantly higher than in CHB patients (2.4 µg/mL) and healthy controls (2.4 µg/mL). In CHB patients receiving PEG-IFN, a significant increase in sCD14 was found after 12-week treatment (median week 0:2.1 µg/mL; week 12:3.7 µg/mL). After 12-week treatment, the fold change (FC = w12/w0) in sCD14 was significantly higher in responders compared to nonresponders (HBeAg seroconversion: median FCresponder  = 2.1 vs FCnonresponder  = 1.6; HBeAg loss: median FCresponder  = 2.2 vs FCnonresponder  = 1.5). Receiver operating characteristic curves demonstrated that FC-sCD14wk12/wk0 levels can be of significant value as a stopping rule to select patients at week 12 who are not likely to benefit from further PEG-IFN treatment.

HBV-Derived Synthetic Long Peptide Can Boost CD4+ and CD8+ T-Cell Responses in Chronic HBV Patients Ex Vivo.

Background: Vaccination with synthetic long peptides (SLP) is a promising new treatment strategy for chronic hepatitis B virus (CHB). SLP can induce broad T-cell responses for all HLA types. Here we investigated the ability of a prototype HBV-core (HBc)-sequence-derived SLP to boost HBV-specific T cells in CHB patients ex vivo. Methods: HBc-SLP was used to assess cross-presentation by monocyte-derived dendritic cells (moDC) and BDCA1+ blood myeloid DC (mDC) to engineered HBV-specific CD8+ T cells. Autologous SLP-loaded and toll-like receptor (TLR)-stimulated DC were used to activate patient HBc-specific CD8+ and CD4+ T cells. Results: HBV-SLP was cross-presented by moDC, which was further enhanced by adjuvants. Patient-derived SLP-loaded moDC significantly increased autologous HBcAg18-27-specific CD8+ T cells and CD4+ T cells ex vivo. HBV-specific T cells were functional as they synthesized tumor necrosis factor-alpha and interferon-gamma. In 6/7 of patients blockade of PD-L1 further increased SLP effects. Also, importantly, patient-derived BDCA1+ mDC cross-presented and activated autologous T-cell responses ex vivo. Conclusions: As a proof of concept, we showed a prototype HBc-SLP can boost T-cell responses in patients ex vivo. These results pave the way for the development of a therapeutic SLP-based vaccine to induce effective HBV-specific adaptive immune responses in CHB patients.

Transcriptional patterns associated with BDCA3 expression on BDCA1+ myeloid dendritic cells.

Myeloid dendritic cells, including BDCA3hi DCs and BDCA1+ DCs (hereafter dubbed DC1 and DC2 for clarity), play a pivotal role in the induction and regulation of immune responses. Interestingly, a fraction of DC2 also express low to intermediate levels of BDCA3. It is unknown whether BDCA3+ DC2 also share other traits with DC1 that are absent in BDCA3- DC2 and/or whether BDCA3 expression renders DC2 functionally distinct from their BDCA3-lacking counterparts. Here, we used expression analysis on a predefined set of immunology-related genes to determine divergence between BDCA3-positive and BDCA3-negative DC2 and their relation to bona fide BDCA3hi DC1. Results showed that mRNA fingerprints of BDCA3+ DC2 and BDCA3- DC2 are very similar, and clearly distinct from that of DC1. Differences in mRNA expression, however, were observed between BDCA3+ DC2 and BDCA3- DC2 that pointed toward a more activated status of BDCA3+ DC2. In line with this, higher steady state maturation marker expression and TLR-induced maturation marker expression and inflammatory cytokine production by BDCA3+ DC2 were observed. This dataset provides insight into the relationship between myeloid DC populations and contributes to further understanding of DC immunobiology.

BDCA3(+)CLEC9A(+) human dendritic cell function and development.

Dendritic cells (DC) are the most potent antigen presenting cells (APC). They comprise a family of different subsets and play an essential role in the induction and regulation of immune responses. Recently, gene expression profiling identified BDCA3(+)CLEC9A(+) DC as a separate human DC subset. This subset was identified in blood, where they represent the smallest population of human DC, as well as in lymphoid and peripheral tissues. This review summarizes the phenotypic, functional and developmental characteristics of BDCA3(+)CLEC9A(+) DC in relation to their mouse equivalents CD8α(+) DC and CD103(+) DC and other human DC subsets. Apart from being potent antigen presenting cells, their specialized functional capacities compared to other human DC subsets, indicate that these BDCA3(+)CLEC9A(+) DC are of major importance in the induction of anti-viral and anti-tumor immunity. Further characterization of their functional properties, developmental pathways and underlying molecular mechanisms may identify target molecules to fully exploit the immune modulatory function of BDCA3(+)CLEC9A(+) DC and potential use of these cells in immunotherapy.

Hepatitis B Virus Surface Antigen Activates Myeloid Dendritic Cells via a Soluble CD14-Dependent Mechanism.

UNLABELLED: Hepatitis B virus (HBV) infection can cause chronic liver disease, which is associated with increased risk of liver cirrhosis, liver failure, and liver cancer. Clearance of HBV infection requires effective HBV-specific immunity; however, the immunological mechanisms that determine the development of effective HBV-specific immunity are poorly understood. Dendritic cells (DC) play a pivotal role in the regulation of antiviral immunity. Here, we investigated the interaction between HBV surface antigen (HBsAg), the main envelope glycoprotein of HBV, and BDCA1(+) myeloid dendritic cells (mDC). Exposure of peripheral blood-derived BDCA1(+) mDC to HBsAg resulted in strong DC maturation, cytokine production, and enhanced capacity to activate antigen-specific cytotoxic T cells (CTLs). By using neutralizing antibodies, crucial roles for CD14 and Toll-like receptor 4 (TLR4) in HBsAg-mediated BDCA1(+) mDC maturation were identified. Concordantly, HBsAg-mediated DC maturation required fetal calf serum (FCS) or human plasma, naturally containing soluble CD14 (sCD14). Intriguingly, HBsAg-induced DC maturation was significantly reduced in umbilical cord blood plasma, which contained less sCD14 than adult plasma, indicating that sCD14 is an important host factor for recognition of HBsAg by DC and subsequent DC activation. A direct interaction between sCD14 and HBsAg was demonstrated by using enzyme-linked immunosorbent assay (ELISA). Moreover, sCD14-HBsAg complexes were detected both in vitro and in sera of HBV-infected patients. The abundance of sCD14-HBsAg complexes varied between chronic HBV disease stages and correlated with activation of BDCA1(+) mDC in vivo We conclude that HBsAg activates BDCA1(+) DC via an sCD14-dependent mechanism. These findings provide important novel insights into the initiation of HBV-specific immunity and facilitate development of effective immunotherapeutic interventions for HBV. IMPORTANCE: Hepatitis B virus (HBV) infection is a significant health problem, as it causes progressive liver injury and liver cancer in patients with chronic HBV infection, which affects approximately 250 million individuals worldwide. Some of the infected adults and the majority of neonates fail to mount an effective immune response and consequently develop chronic infection. The viral and host factors involved in the initiation of effective HBV-specific immune responses remain poorly understood. Here we identified CD14 and TLR4 as receptors for HBsAg, the main HBV envelope antigen. HBsAg induced strong maturation of dendritic cells (DC), which have a central role in regulation of virus-specific immunity. These results provide essential novel insights into the mechanisms underlying the initiation of HBV-specific immunity. Intriguingly, since neonates have naturally low sCD14, the finding that serum-derived sCD14 is a crucial host factor for recognition of HBsAg by DC may have implications for immunity of neonates to HBV infection.

BDCA3 expression is associated with high IFN-λ production by CD34(+)-derived dendritic cells generated in the presence of GM-CSF, IL-4, and/or TGF-ß.

High BDCA3 expression is associated with a specific human IFN-λ-producing dendritic cell (DC) subset. However, BDCA3 has also been detected on other DC subsets. Thus far, development and function of BDCA3 expression on DCs remains poorly understood. Human Langerhans cells (LCs) and interstitial DCs (intDCs) can be generated in vitro by differentiation of CD34(+) hematopoietic progenitors via distinct precursor DCs (preDCs), CD1a(+) preDCs, and CD14(+) preDCs, respectively. Here, we identified BDCA3 expression in this well-known GM-CSF/TNF-α-driven culture system and described the effect of IL-4 and/or TGF-ß on induction of BDCA3 expression. In control or TGF-ß cultures, BDCA3 was only detected on CD14(+) preDC-derived intDCs. IL-4 induced BDCA3 expression in both CD14(+)-derived and CD1a(+)-derived cultures. TGF-ß and IL-4 together further increased CD14(+)-derived and CD1a(+)-derived BDCA3(+) DC frequencies, which partly expressed CLEC9A, but were not identical to the BDCA3(high) CLEC9A(+) DC subset in vivo. Importantly, BDCA3(+) cells, but not BDCA3(-) cells, in this system produced high IFN-λ levels upon polyinosinic:polycytidylic acid (polyI:C) stimulation. This culture system, in which BDCA3 expression is preferentially associated with the intDC lineage and IFN-λ-producing capacity, will greatly contribute to further research on the function and regulation of BDCA3 expression and IFN-λ production by DCs.

Kupffer cells interact with hepatitis B surface antigen in vivo and in vitro, leading to proinflammatory cytokine production and natural killer cell function.

BACKGROUND: Based on their localization, Kupffer cells (KCs) likely interact with hepatitis B virus (HBV). However, the role of KCs in inducing immunity toward HBV is poorly understood. Therefore, the interaction of hepatitis B surface antigen (HBsAg) and KCs, and possible functional consequences, were assessed. METHODS: KCs in liver tissue from patients with chronic HBV were analyzed for presence of HBsAg and their phenotype, and compared with KCs in control liver tissue. Liver graft perfusate-derived KCs and in vitro-generated monocyte-derived macrophages were investigated for functional interaction with patient-derived HBsAg. RESULTS: Intrahepatic KCs were HBsAg positive and more activated than those from control livers. KCs internalized HBsAg in vitro, which did not change their phenotype, but strongly induced proinflammatory cytokine production. Additionally, monocyte-derived macrophages also interacted with HBsAg, leading to activation and cytokine production. Furthermore, HBsAg-exposed macrophages and KC activated natural killer (NK) cells, resulting in increased CD69 expression and interferon-γ production. CONCLUSIONS: KCs directly interact with HBsAg in vivo and in vitro. HBsAg-induced cytokine production by KCs and monocyte-derived macrophages and subsequent NK cell activation may be an early event in viral containment and may support induction of HBV-specific immunity upon HBV infection, but may also contribute to liver pathology.

The role of Kupffer cells in hepatitis B and hepatitis C virus infections.

Globally, over 500 million people are chronically infected with the hepatitis B virus (HBV) or hepatitis C virus (HCV). These chronic infections cause liver inflammation, and may result in fibrosis/cirrhosis or hepatocellular carcinoma. Albeit that HBV and HCV differ in various aspects, clearance, persistence, and immunopathology of either infection depends on the interplay between the innate and adaptive responses in the liver. Kupffer cells, the liver-resident macrophages, are abundantly present in the sinusoids of the liver. These cells have been shown to be crucial players to maintain homeostasis, but also contribute to pathology. However, it is important to note that especially during pathology, Kupffer cells are difficult to distinguish from infiltrating monocytes/macrophages and other myeloid cells. In this review we discuss our current understanding of Kupffer cells, and assess their role in the regulation of anti-viral immunity and disease pathogenesis during HBV and HCV infection.

Regulation of dendritic cell development by GM-CSF: molecular control and implications for immune homeostasis and therapy.

Dendritic cells (DCs) represent a small and heterogeneous fraction of the hematopoietic system, specialized in antigen capture, processing, and presentation. The different DC subsets act as sentinels throughout the body and perform a key role in the induction of immunogenic as well as tolerogenic immune responses. Because of their limited lifespan, continuous replenishment of DC is required. Whereas the importance of GM-CSF in regulating DC homeostasis has long been underestimated, this cytokine is currently considered a critical factor for DC development under both steady-state and inflammatory conditions. Regulation of cellular actions by GM-CSF depends on the activation of intracellular signaling modules, including JAK/STAT, MAPK, PI3K, and canonical NF-κB. By directing the activity of transcription factors and other cellular effector proteins, these pathways influence differentiation, survival and/or proliferation of uncommitted hematopoietic progenitors, and DC subset-specific precursors, thereby contributing to specific aspects of DC subset development. The specific intracellular events resulting from GM-CSF-induced signaling provide a molecular explanation for GM-CSF-dependent subset distribution as well as clues to the specific characteristics and functions of GM-CSF-differentiated DCs compared with DCs generated by fms-related tyrosine kinase 3 ligand. This knowledge can be used to identify therapeutic targets to improve GM-CSF-dependent DC-based strategies to regulate immunity.

PI3K-PKB hyperactivation augments human plasmacytoid dendritic cell development and function.

Plasmacytoid dendritic cells (pDCs) are considered potential tools or targets for immunotherapy. However, current knowledge concerning methodologies to manipulate their development or function remains limited. Here, we investigated the role of the phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB)-mammalian target of rapamycin (mTOR) axis in human pDC development, survival, and function. In vitro pDC generation from human cord blood-derived CD34(+) hematopoietic progenitors was reduced by pharmacologic inhibition of PI3K, PKB, or mTOR activity, and peripheral blood pDCs required PI3K-PKB-mTOR signaling to survive. Accordingly, activity of this pathway in circulating pDCs correlated with their abundance in peripheral blood. Importantly, introduction of constitutively active PKB or pharmacologic inhibition of negative regulator phosphatase and tensin homolog (PTEN) resulted in increased pDC numbers in vitro and in vivo. Furthermore, MHC class II and costimulatory molecule expression, and production of IFN-α and TNF-α, were augmented, which could be explained by enhanced IRF7 and NF-κB activation. Finally, the numerically and functionally impaired pDCs of chronic hepatitis B patients demonstrated reduced PI3K-PKB-mTOR activity. In conclusion, intact PI3K-PKB-mTOR signaling regulates development, survival, and function of human pDCs, and pDC development and functionality can be promoted by PI3K-PKB hyperactivation. Manipulation of this pathway or its downstream targets could be used to improve the generation and function of pDCs to augment immunity.

Identification of a novel CD40 ligand for targeted imaging of inflammatory plaques by phage display.

The CD40/CD40L dyad is deemed to play a central role in several inflammatory processes, including atherosclerosis. As CD40 is overexpressed in atherosclerotic lesions, it constitutes a promising candidate for targeted imaging approaches. Here we describe the design of a novel, selective peptide ligand for CD40 by phage display. A synthetic peptide corresponding with the phage insert NP31 displayed nanomolar affinity for CD40. Affinity was further enhanced by mutimeric presentation of NP31. An essential 11-mer peptide motif was identified by truncation and alanine scan studies. Enriched phage selectively bound human CD40 and homed to inflammatory joints in a murine model of rheumatoid arthritis. NP31 ablated VEGF and IL-6 transcriptional activation and partially inhibited IL-6 production by CD40L-activated endothelial cells. Notably, NP31 did not only alter the biodistribution profile of a streptavidin scaffold but also markedly increased accumulation of the carrier in atherosclerotic aortic lesions of aged ApoE(-/-) mice in a CD40-dependent manner. This potent and selective peptide ligand has potential for targeted imaging and drug delivery approaches in CD40-dependent inflammatory disorders such as atherosclerosis.

Intrahepatic natural killer cell activation, but not function, is associated with HBsAg levels in patients with HBeAg-negative chronic hepatitis B.

BACKGROUND & AIMS: Natural killer (NK) cells play an important role in the immune response to viruses. As the hepatitis B virus (HBV) replicates in hepatocytes, examination of the liver of chronic hepatitis B (CHB) patients is crucial to better understand the role of NK cells in HBV. HBeAg-negative CHB differs in many aspects from HBeAg-positive CHB, and until now little is known about the intrahepatic NK cell response in HBeAg-negative patients. Intrahepatic immune control might be different in HBeAg-negative as compared with HBeAg-positive patients. METHODS: Liver NK cells were investigated in 21 HBeAg-positive and 35 HBeAg-negative CHB patients. Biopsy specimens were processed for routine histopathology and staging according to Ishak scores. Intrahepatic and blood NK cell frequencies, activation status and function of NK cells were analysed by flow cytometry. RESULTS: In HBeAg-negative CHB patients, compared to blood, liver NK cells displayed a more activated phenotype and stimulation further increased the activation status, but production of IFN-γ was markedly less. There was no difference with HBeAg-positive CHB. Only in HBeAg-negative CHB, but not in HBeAg-positive CHB, NK cell activation was inversely correlated with HBsAg levels. CONCLUSIONS: The present study indicates that liver NK cells of CHB have a higher activation status compared to blood. However, they are not capable to increase cytokine production above levels reached by activated blood NK cells. In HBeAg-negative CHB, the levels of HBsAg may contribute to the incapacity of activated liver NK cells to increase cytokine production.

Polymorphisms near IL28B and serologic response to peginterferon in HBeAg-positive patients with chronic hepatitis B.

BACKGROUND & AIMS: A limited number of patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B respond to treatment with peginterferon alfa (PEG-IFN). We investigated whether IL28B genotypes are associated with response. METHODS: We studied 205 HBeAg-positive patients who were treated with PEG-IFN (some were also treated with lamivudine) at 11 European and Asian hospitals; genotype analysis was performed for IL28B rs12980275 and rs12979860. Response was defined as HBeAg loss with the appearance of antibodies to hepatitis B e antigen (anti-HBe) at the end of PEG-IFN therapy (HBeAg seroconversion), along with HBeAg seroconversion and hepatitis B surface antigen clearance during long-term follow-up. RESULTS: The patients were infected with hepatitis B virus (HBV) genotypes A (13%), B (20%), C (47%), and D (13%). The proportions of IL28B genotypes were 77%, 19%, and 5% for AA/AG/GG at rs12980275 and also for CC/CT/TT at rs12979860, respectively. IL28B genotype was significantly associated with HBeAg seroconversion at the end of treatment (P < .001); the adjusted odds ratio for seroconversion was 3.16 (95% confidence interval [CI], 1.26-8.52; P = .013) for AA versus AG/GG at rs12980275 after adjustment for HBV genotype, age, levels of HBV DNA and alanine aminotransferase, and combination therapy. IL28B genotype was independently associated with an increased probability of HBeAg seroconversion during long-term follow-up (adjusted hazard ratio [HR], 2.14; 95% CI, 1.14-4.31; P = .018 for AA vs AG/GG by Cox regression analysis). Similar results were obtained for rs12979860. IL28B genotype was also associated with hepatitis B surface antigen clearance (HR, 3.47 for AA vs AG/GG; 95% CI, 1.04-13.48; P = .042). CONCLUSIONS: Polymorphisms near IL28B are independently associated with serologic response to PEG-IFN in patients with HBeAg-positive chronic hepatitis B.

CD64 distinguishes macrophages from dendritic cells in the gut and reveals the Th1-inducing role of mesenteric lymph node macrophages during colitis.

Dendritic cells (DCs) and monocyte-derived macrophages (MΦs) are key components of intestinal immunity. However, the lack of surface markers differentiating MΦs from DCs has hampered understanding of their respective functions. Here, we demonstrate that, using CD64 expression, MΦs can be distinguished from DCs in the intestine of both mice and humans. On that basis, we revisit the phenotype of intestinal DCs in the absence of contaminating MΦs and we delineate a developmental pathway in the healthy intestine that leads from newly extravasated Ly-6C(hi) monocytes to intestinal MΦs. We determine how inflammation impacts this pathway and show that T cell-mediated colitis is associated with massive recruitment of monocytes to the intestine and the mesenteric lymph node (MLN). There, these monocytes differentiate into inflammatory MΦs endowed with phagocytic activity and the ability to produce inducible nitric oxide synthase. In the MLNs, inflammatory MΦs are located in the T-cell zone and trigger the induction of proinflammatory T cells. Finally, T cell-mediated colitis develops irrespective of intestinal DC migration, an unexpected finding supporting an important role for MLN-resident inflammatory MΦs in the etiology of T cell-mediated colitis.