Lymphoid organs, in which antigen presenting cells (APCs) are in close proximity to T cells, are the ideal microenvironment for efficient priming and amplification of T-cell responses. However, the systemic delivery of vaccine antigens into dendritic cells (DCs) is hampered by various technical challenges. Here we show that DCs can be targeted precisely and effectively in vivo using intravenously administered RNA-lipoplexes (RNA-LPX) based on well-known lipid carriers by optimally adjusting net charge, without the need for functionalization of particles with molecular ligands. The LPX protects RNA from extracellular ribonucleases and mediates its efficient uptake and expression of the encoded antigen by DC populations and macrophages in various lymphoid compartments. RNA-LPX triggers interferon-α (IFNα) release by plasmacytoid DCs and macrophages. Consequently, DC maturation in situ and inflammatory immune mechanisms reminiscent of those in the early systemic phase of viral infection are activated. We show that RNA-LPX encoding viral or mutant neo-antigens or endogenous self-antigens induce strong effector and memory T-cell responses, and mediate potent IFNα-dependent rejection of progressive tumours. A phase I dose-escalation trial testing RNA-LPX that encode shared tumour antigens is ongoing. In the first three melanoma patients treated at a low-dose level, IFNα and strong antigen-specific T-cell responses were induced, supporting the identified mode of action and potency. As any polypeptide-based antigen can be encoded as RNA, RNA-LPX represent a universally applicable vaccine class for systemic DC targeting and synchronized induction of both highly potent adaptive as well as type-I-IFN-mediated innate immune mechanisms for cancer immunotherapy.

Systemic RNA delivery to dendritic cells exploits antiviral defence for cancer immunotherapy

Type I interferons (IFNs) are known for their key role in antiviral immune responses. In this Review, we discuss accumulating evidence indicating that type I IFNs produced by malignant cells or tumour-infiltrating dendritic cells also control the autocrine or paracrine circuits that underlie cancer immunosurveillance. Many conventional chemotherapeutics, targeted anticancer agents, immunological adjuvants and oncolytic viruses are only fully efficient in the presence of intact type I IFN signalling. Moreover, the intratumoural expression levels of type I IFNs or of IFN-stimulated genes correlate with favourable disease outcome in several cohorts of patients with cancer. Finally, new anticancer immunotherapies are being developed that are based on recombinant type I IFNs, type I IFN-encoding vectors and type I IFN-expressing cells.

Type I interferons in anticancer immunity

The interferons (IFNs) are a family of cytokines that protect against disease by direct effects on target cells and by activating immune responses. The production and actions of IFNs are finely tuned to achieve maximal protection and avoid the potential toxicity associated with excessive responses. IFNs are back in the spotlight owing to mounting evidence that is reshaping how we can exploit this pathway therapeutically. As IFNs can be produced by, and act on, both tumour cells and immune cells, understanding this reciprocal interaction will enable the development of improved single-agent or combination therapies that exploit IFN pathways and new 'omics'-based biomarkers to indicate responsive patients.

Antitumour actions of interferons: implications for cancer therapy

Two decades ago successful transfection of antigen presenting cells (APC) in vivo was demonstrated which resulted in the induction of primary adaptive immune responses. Due to the good biocompatibility of plasmid DNA, their cost-efficient production and long shelf life, many researchers aimed to develop DNA vaccine-based immunotherapeutic strategies for treatment of infections and cancer, but also autoimmune diseases and allergies. This review aims to summarize our current knowledge on the course of action of DNA vaccines, and which factors are responsible for the poor immunogenicity in human so far. Important optimization steps that improve DNA transfection efficiency comprise the introduction of DNA-complexing nano-carriers aimed to prevent extracellular DNA degradation, enabling APC targeting, and enhanced endo/lysosomal escape of DNA. Attachment of virus-derived nuclear localization sequences facilitates nuclear entry of DNA. Improvements in DNA vaccine design include the use of APC-specific promotors for transcriptional targeting, the arrangement of multiple antigen sequences, the co-delivery of molecular adjuvants to prevent tolerance induction, and strategies to circumvent potential inhibitory effects of the vector backbone. Successful clinical use of DNA vaccines may require combined employment of all of these parameters, and combination treatment with additional drugs.

https://www.mdpi.com/1422-0067/19/11/3605/pdf

DNA Vaccines-How Far From Clinical Use?

Type I Interferon in Chronic Virus Infection and Cancer

http://www.jidonline.org/article/S0022202X22024320/pdf

484 Melatonin induces melanoma cell death and synergizes with BRAF/MEK inhibitors by altering cell bioenergetics

http://www.jidonline.org/article/S0022202X23005079/pdf

327 The early reactivation of resident CD8+ memory t cells depends on cross-presentation of antigen by langerhans cells in the epidermis

http://www.jidonline.org/article/S0022202X23005328/pdf

352 Endothelial cells – additional targets for alpha7 nicotinic acetylcholine receptor agonists in the future treatment of skin fibrosis and scleroderma?

Targeting neutrophil extracellular traps (NETs) ameliorates inflammation in murine psoriasiform dermatitis.

Background: Caregiving can be a long-term stressor, which is associated with mental and physical health complaints. Understanding protective factors is crucial. Here, we investigated the associations between relationship quality between caregiver (CG) and care recipient (CR) and CG’s depression and perceived stress, and physiological stress markers such as C-reactive protein (CRP) and cortisol levels. Methods: N = 36 (11 male; 61.7 ± 11.4 years) informal caregivers participated. CRP was measured in Dried Blood Spots. Cortisol levels were assessed from bedtime saliva samples as well as from hair samples. Relationship quality was assessed by means of a self-developed scale. Ratings were dichotomized as positive or neutral/negative. CG’s depression and perceived stress were assessed by means of standardized questionnaires (PHQ-9 and PSS-10). Results: A positive relationship was associated with less perceived stress as well as with lower depression (both p < .003, Cohen’s d > 4.5). No significant differences were found for the physiological markers (all p > .05, Cohen’s d > 0.56). However, CRP levels were related with perceived stress (r = .48, p = .012). Conclusion: Our pilot study shows that relationship quality is associated with CG’s mental health and perceived stress. More research with larger sample sizes is needed to investigate whether this is also associated with CG’s physical health. Inflammatory markers such as CRP levels are promising measures. Background: Major depressive disorder (MDD) is a severe mental disorder associated with alterations of the innate immune system. Changes in blood monocytes have been found in MDD, whereas knowledge of dendritic cells (DCs) in depression is limited. DCs are professional antigen-presenting cells comprising various subsets such as CD1c+ and CD141+ DCs and plasmacytoid DCs (pDCs). Here, we investigated the proportions of DC subsets in MDD and their association with depressive symptoms and severity of MDD. Methods: To analyse DC subsets in MDD, blood samples from healthy controls (HC, n=37) and depressed patients (n=61) were analysed at baseline and after six weeks of therapy using multi-parameter flow cytometry. Additionally, patients were stratified according to MDD severity using Hamilton Rating Scale for Depression (HAM-D) Background: Considering the individually varying age-related decline of physical and cognitive capacity in relation to the functionality of the immune system, this study aimed to analyze the correlation of personal characteristics with cardiorespiratory fitness (CRF), and with markers summarizing the multivariate nature of ‘immune age’ and ‘general intelligence’. Methods: For the cross-sectional baseline examinations within the longitudinal ’Dortmund Vital Study’ (DVS) comprising 355 females and 222 males (20-70 years of age, body-mass-index (BMI) 17-54 kg/m²), peripheral blood mononuclear cell frequencies were determined by flow cytometry. These measurements were submitted to principal component regression approximating ‘IMM-AGE’, an advanced immune age score. Likewise, multivariate analyses of fifteen neuropsychological tests produced the g factor operationalizing general intelligence adjusted for sex and age. CRF was assessed by the power output standardized for body weight while performing the bicycle ergometer test PWC130. Bivariate and partial Pearson correlations were calculated. Results: While bivariate correlations indicated significantly lower CRF with increasing BMI, chronological and immune age, and for females compared to males, partial correlations adjusting for the other predictors remained significant for Sex, BMI and immune age, but not for chronological age. No significant correlations occurred between personal characteristics and the g factor; however, there was a small, but significant positive correlation between global intelligence and CRF. Conclusion: In summary, our results indicate a potential role for the immune age in explaining the inter-individual variability in cardiorespiratory fitness, whereas predictors for general intelligence will require further study including the ongoing longitudinal examinations within the DVS cohort. Background: to aging of the system, vaccinations are often less effective in older persons. The 'immune age' tries to reflect age-related changes in the immune system, which vary between and Methods: We developed an immune age score integrating a minimal set of immune cell populations determined by flow cytometry. Immune age and SARS-CoV-2 spike-RBD-specific antibodies were quantified in peripheral blood of 724 vaccinated adults. In addition, epidemiological data were collected by questionnaire. Results: Our results show a strong correlation of antibody titers with immunological and chronological age. However, the immune age scores of women matched those of men who were about 6 years older. Antibody titers were also higher in women, suggesting an additional influence of sex on immune function. Interestingly, the immune age score of a cohort of 97 male professional firefighters was lower than that of other men and comparable to that of women of the same age. This hints towards positive effects of physical fitness on immunological age independent of sex. Conclusion: Overall, the immune age score is a valuable tool to study vaccination success as function of immunological aging and its correlation with sex and physical fitness. Background: We previously demonstrated associations between the presence of psychological trauma and Major Depressive Disorder (MDD) and immune cell telomere length (TL) and mitochondrial respiratory activity. Here, we investigated the proposed anti-ageing effects of endogenous circulating levels of the steroid hormone dehydroepiandrosterone (DHEA) on these associations. Methods: Blood samples were collected from n=22 inpatients with MDD and n=22 non-depressed controls. Lifetime traumatic events were assessed by self-report using the Essener Trauma Inventory. DHEA levels were measured by immunoassay. Immune cell TL was quantified in kilobases using qFISH and mitochondrial respiration was measured applying high-resolution respirometry. Results: Higher trauma load was associated with lower DHEA concentration (r=-.25, p=.03) and lower DHEA concentration associated with more depression-related fatigue symptoms in MDD patients (r=-.45, p=.01). In addition, we observed that DHEA levels positively associated with TL in memory CD4+ T-cells (r=.39, p=.01) as well as in naïve and memory CD8+ T cells (r=.46, p=.002 and r=.47, p=.002, respectively). DHEA concentration also related to routine (r=.31, p=.04) and uncoupled respiration (r=.34, p=.04) in leukocytes. Mediational analysis (path analyses with bootstrapping) suggested that the effect of trauma load on memory CD8+ T-cell TL was mediated by DHEA concentration (ab=-.11, CI95%: -.22 to -.01). Finally, in MDD patients, DHEA concentration mediated the effect of trauma load on depression-related fatigue (ab=.10, CI95%: .02 to .21). Background: DNA damage and the capacity to repair damaged DNA has been associated with the pathogenesis of several diseases such as cancer. While it is well known that external mutagenic agents can induce DNA damage, less is known about endogenous contributors to genomic instability. The aim of this study was to investigate whether excess body weight as a physiological factor and vital exhaustion as a psychological factor would be associated with basal levels of DNA damage as well as DNA repair capacity. Methods: In a cross-sectional between-subject design we recruited 53 apparently healthy men within the normal to non-obese overweight range (mean BMI: 25.2±.5) who were either vitally exhausted (VE) (VE-score≥10) or non-exhausted (VE-score≤3). Vital exhaustion was assessed using the Maastricht Vital Exhaustion Questionnaire. We assessed DNA damage and repair in terms of strand breaks in PBMCs by means of the automated Fluorimetric Detection of Alkaline Unwinding (FADU) assay. DNA repair capacity was assessed by repeatedly measuring the amount of intact DNA up to 90 minutes after standardized X-irradiation of the cells. Results: General linear models revealed that elevated levels of basal DNA damage (β=-.34,p=.013,f=0.33) as well as impaired capacity to repair damaged DNA (F(1/50)=5.40,p=.024,f=.33) with increasing BMI, but not with vital exhaustion (p’s≥.63). Conclusion: Our findings point to DNA integrity impairments with increasing BMI, already in Results: Higher DRD1 expression on B cells (p<0.001) and dopamine levels in PBMCs (p<0.05) were found for RA women compared to HC. Positive correlations between DRD1 expression, disease duration (p<0.01) and Hannover Functional Questionnaire parameter FFbH (p<0.05) were obtained. D1-like stimulation resulted in higher HLA-DR expression on B cells (p<0.05), more proinflammatory and less antiinflammatory cytokine secretion (p<0.01) for RA compared to HC. Conclusion: Elevated DRD1 and dopamine levels in diseased women suggest that the dopaminergic pathway is overactivated in RA. Along with present correlations with RA parameters a proinflammatory contribution is indicated. This is supported by an increased HLA-DR expression and a stronger proinflammatory cytokine profile after D1-like stimulation for RA than HC. However, the exact mechanism needs to be further investigated. Background: Chemokines and their receptors regulate inflammatory processes in major depressive disorder (MDD). Here, we characterize the expression pattern of the C-C chemokine receptor 4 (CCR4) and its ligands CCL17 and CCL22 in MDD and its clinical relevance in predicting disease severity. Methods: Expression of CCR4 on peripheral blood lymphocytes and serum CCL17/CCL22 levels were measured using multiparameter flow cytometry and multiplex assays in 33 depressed inpatients at baseline (T0) and after 6-week multimodal treatment (T1) compared with 21 healthy controls (HC). Using stratified an

Verena Raker

Papers

484 Melatonin induces melanoma cell death and synergizes with BRAF/MEK inhibitors by altering cell bioenergetics

327 The early reactivation of resident CD8+ memory t cells depends on cross-presentation of antigen by langerhans cells in the epidermis

352 Endothelial cells – additional targets for alpha7 nicotinic acetylcholine receptor agonists in the future treatment of skin fibrosis and scleroderma?

Targeting neutrophil extracellular traps (NETs) ameliorates inflammation in murine psoriasiform dermatitis.

14th GEBIN Conference 2022 and AKNEI-DGFI Satellite Meeting