Adenovirus-α-Defensin Complexes Induce NLRP3-Associated Maturation of Human Phagocytes via Toll-Like Receptor 4 Engagement.

Intramuscular delivery of human adenovirus (HAdV)-based vaccines leads to rapid recruitment of neutrophils, which then release antimicrobial peptides/proteins (AMPs). How these AMPs influence vaccine efficacy over the subsequent 24 h is poorly understood. In this study, we asked if human neutrophil protein 1 (HNP-1), an α-defensin that influences direct and indirect innate immune responses to a range of pathogens, impacts the response of human phagocytes to three HAdV species/types (HAdV-C5, -D26, -B35). We show that HNP-1 binds to the capsids and redirects HAdV-C5, -D26, and -B35 to Toll-like receptor 4 (TLR4), which leads to internalization, an NLRP3-mediated inflammasome response, and interleukin 1 beta (IL-1ß) release. Surprisingly, IL-1ß release was not associated with notable disruption of plasma membrane integrity. These data further our understanding of HAdV vaccine immunogenicity and may provide pathways to extend the efficacy. IMPORTANCE This study examines the interactions between danger-associated molecular patterns and human adenoviruses, and their impact on vaccines. HAdVs and HNP-1 can interact, and these interactions will modify the response of antigen-presenting cells, which will influence vaccine efficacy.

Human innate lymphoid cell activation by adenoviruses is modified by host defense proteins and neutralizing antibodies.

Innate lymphoid cells (ILCs), the complements of diverse CD4 T helper cells, help maintain tissue homeostasis by providing a link between innate and adaptive immune responses. While pioneering studies over the last decade have advanced our understanding how ILCs influence adaptive immune responses to pathogens, far less is known about whether the adaptive immune response feeds back into an ILC response. In this study, we isolated ILCs from blood of healthy donors, fine-tuned culture conditions, and then directly challenged them with human adenoviruses (HAdVs), with HAdVs and host defense proteins (HDPs) or neutralizing antibodies (NAbs), to mimic interactions in a host with pre-existing immunity. Additionally, we developed an ex vivo approach to identify how bystander ILCs respond to the uptake of HAdVs ± neutralizing antibodies by monocyte-derived dendritic cells. We show that ILCs take up HAdVs, which induces phenotypic maturation and cytokine secretion. Moreover, NAbs and HDPs complexes modified the cytokine profile generated by ILCs, consistent with a feedback loop for host antiviral responses and potential to impact adenovirus-based vaccine efficacy.

Lactoferrin Retargets Human Adenoviruses to TLR4 to Induce an Abortive NLRP3-Associated Pyroptotic Response in Human Phagocytes.

Despite decades of clinical and preclinical investigations, we still poorly grasp our innate immune response to human adenoviruses (HAdVs) and their vectors. In this study, we explored the impact of lactoferrin on three HAdV types that are being used as vectors for vaccines. Lactoferrin is a secreted globular glycoprotein that influences direct and indirect innate immune response against a range of pathogens following a breach in tissue homeostasis. The mechanism by which lactoferrin complexes increases HAdV uptake and induce maturation of human phagocytes is unknown. We show that lactoferrin redirects HAdV types from species B, C, and D to Toll-like receptor 4 (TLR4) cell surface complexes. TLR4-mediated internalization of the HAdV-lactoferrin complex induced an NLRP3-associated response that consisted of cytokine release and transient disruption of plasma membrane integrity, without causing cell death. These data impact our understanding of HAdV immunogenicity and may provide ways to increase the efficacy of HAdV-based vectors/vaccines.

A review of 65 years of human adenovirus seroprevalence.

Introduction: Human adenovirus (HAdV)-derived vectors have been used in numerous pre-clinical and clinical trials during the last 40 years. Current research in HAdV-based vaccines focuses on improving transgene immunogenicity and safety. Because pre-existing humoral immunity against HAdV types correlate with reduced vaccine efficacy and safety, many groups are exploring the development of HAdV types vectors with lower seroprevalence. However, global seroepidemiological data are incomplete. Areas covered: The goal of this review is to centralize 65 years of research on (primarily) HAdV epidemiology. After briefly addressing adenovirus biology, we chronical HAdV seroprevalence studies and highlight major milestones. Finally, we analyze data from about 50 studies with respect to HAdVs types that are currently used in the clinic, or are in the developmental pipeline. Expert opinion: Vaccination is among the most efficient tools to prevent infectious disease. HAdV-based vaccines have undeniable potential, but optimization is needed and antivector immunity remains a challenge if the same vectors are to be administrated to different populations. Here, we identify gaps in our knowledge and the need for updated worldwide epidemiological data.

Thymoquinone Potently Enhances the Activities of Classically Activated Macrophages Pulsed with Necrotic Jurkat Cell Lysates and the Production of Antitumor Th1-/M1-Related Cytokines.

Antitumor activity of classically activated macrophage (Mϕ) may be impaired within the tumors, spleen, and bone marrow. Thus, it is possible to boost its antitumor activity after its pulsing with necrotic tumor cell lysates combined with an adjuvant. We set out to determine the potential adjuvant effects of thymoquinone (TQ; 2-isopropyl-5-methyl-1,4-benzoquinone, C10H12O2) on both functional activities of classically activated Mϕs, pulsed or not with necrotic Jurkat T cell line lysates (NecrJCL), and the balance of antitumor cytokines (ATCs) versus immunosuppressive cytokines (ISCs) during crosstalk with autologous human CD4+ T cells. We found that TQ treatment resulted in a significant upregulation of phagocytic activity, respiratory burst, the production of interleukin-2 (IL-2), IL-6, and IL-17 in NecrJCL-pulsed Mϕ co-culture system, and, conversely, in downregulation of the production of IL-6, IL-17, nitric oxide (NO), and arginase activity in nonpulsed TQ-treated Mϕs co-culture system. In addition, TQ has also shown low upregulation effect on the production of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and IL-1ß, pathogen killing capacity and H2O2 in NecrJCL-pulsed Mϕs co-cultures. Moreover, TQ significantly downregulated arginase activity, and significantly upregulated inducible NO synthase (iNOS) activity-to-arginase activity ratio in NecrJCL-pulsed Mϕ co-cultures. Furthermore, TQ downregulated IL-10-to-IL-17 ratio and total cellular cholesterol content (ttcCHOL), but upregulated the ratios of IL-1ß-to-IL-4, IL-1ß-to-IL-10, IFN-γ-to-IL-4, IFN-γ-to-IL-10, TNF-α-to-IL-4, TNF-α-to-IL-10, and combined proinflammatory cytokines (PICs)-to-anti-inflammatory cytokines (AICs) in NecrJCL-pulsed Mϕs co-culture system, whereas significant differences were highlighted only for IL-10-to-IL-17, IFN-γ-to-IL-10, and PICs-to-AICs ratios. Our outcomes demonstrated that TQ can act as potent adjuvant for enhancing both the functional activities of NecrJCL-pulsed Mϕ and the production of ATCs during their interplay with CD4+ T cells.

Deoxynivalenol inhibits the expression by goblet cells of intestinal mucins through a PKR and MAP kinase dependent repression of the resistin-like molecule ß.

SCOPE: The food-associated mycotoxin deoxynivalenol (DON) is known to affect intestinal functions. However, its effect on intestinal mucus is poorly characterized. METHODS AND RESULTS: We analyzed the effects of DON on human goblet cells (HT29-16E cells) and porcine intestinal explants. Results showed that subtoxic doses of DON (as low as 1 µM) decreased mucin (MUC) production. qPCR analysis demonstrated that this inhibition was due to a specific decrease in the level of mRNA encoding for the intestinal membrane-associated (MUC1) and the secreted MUCs (MUC2, MUC3). Mechanistic studies demonstrated that DON effect relied on the activation of the protein kinase R and the mitogen-activated protein kinase p38 ultimately leading to the inhibition of the expression of resistin-like molecule beta, a known positive regulator of MUC expression. CONCLUSION: Taken together, our results show that at low doses found in food and feed, DON is able to affect the expression and production of MUCs by human and animal goblet cells. Due to the important role of MUCs in the barrier function and in the interaction of commensal bacteria with the host, such effect could explain the observed modifications in the microbial diversity and the increased susceptibility to enteric infection following exposure to DON.