Immune Stimuli Research Articles

Acquired hemophilia A following COVID-19 vaccination – The importance of prompt diagnosis: A case report

Acquired hemophilia A (AHA) is a rare coagulopathy characterized by hemorrhagic manifestations. It has been linked to various conditions, including autoimmune disorders, drugs, tumors, lymphoproliferative disorders, and infections. We present a case of AHA in a 71-year-old male patient with cutaneous hematoma occurring 8 days after vaccination for COVID-19. This report aims to highlight the risk of FVIII inhibitor development following an immune stimulus, thus improving our knowledge regarding possible vaccination-related adverse events. Furthermore, we underline how the potential risk of not recognizing disease manifestations promptly, together with specific coagulation alterations, could significantly affect the patient's outcome. Adequate management plans and the diffusion of shared guidelines are of fundamental importance in order to prevent the development of life-threatening complications and initiate appropriate treatment as soon as possible. Data AvailabilityAll data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.

Coelomocyte populations in the sea urchin, Strongylocentrotus purpuratus, undergo dynamic changes in response to immune challenge.

The sea urchin, Strongylocentrotus purpuratus has seven described populations of distinct coelomocytes in the coelomic fluid that are defined by morphology, size, and for some types, by known functions. Of these subtypes, the large phagocytes are thought to be key to the sea urchin cellular innate immune response. The concentration of total coelomocytes in the coelomic fluid increases in response to pathogen challenge. However, there is no quantitative analysis of how the respective coelomocyte populations change over time in response to immune challenge. Accordingly, coelomocytes collected from immunoquiescent, healthy sea urchins were evaluated by flow cytometry for responses to injury and to challenge with either heat-killed Vibrio diazotrophicus, zymosan A, or artificial coelomic fluid, which served as the vehicle control. Responses to the initial injury of coelomic fluid collection or to injection of V. diazotrophicus show significant increases in the concentration of large phagocytes, small phagocytes, and red spherule cells after one day. Responses to zymosan A show decreases in the concentration of large phagocytes and increases in the concentration of small phagocytes. In contrast, responses to injections of vehicle result in decreased concentration of large phagocytes. When these changes in coelomocytes are evaluated based on proportions rather than concentration, the respective coelomocyte proportions are generally maintained in response to injection with V. diazotrophicus and vehicle. However, this is not observed in response to zymosan A and this lack of correspondence between proportions and concentrations may be an outcome of clearing these large particles by the large phagocytes. Variations in coelomocyte populations are also noted for individual sea urchins evaluated at different times for their responses to immune challenge compared to the vehicle. Together, these results demonstrate that the cell populations in sea urchin immune cell populations undergo dynamic changes in vivo in response to distinct immune stimuli and to injury and that these changes are driven by the responses of the large phagocyte populations.

Circadian modulation of microglial physiological processes and immune responses.

Microglia is considered the central nervous system (CNS) resident macrophages that establish an innate immune response against pathogens and toxins. However, the recent studies have shown that microglial gene and protein expression follows a circadian pattern; several immune activation markers and clock genes are expressed rhythmically without the need for an immune stimulus. Furthermore, microglia responds to an immune challenge with different magnitudes depending on the time of the day. This review examines the circadian control of microglia function and the possible physiological implications. For example, we discuss that synaptic prune is performed in the cortex at a certain moment of the day. We also consider the implications of daily microglial function for maintaining biological rhythms like general activity, body temperature, and food intake. We conclude that the developmental stage, brain region, and pathological state are not the only factors to consider for the evaluation of microglial functions; instead, emerging evidence indicates that circadian time as an essential aspect for a better understanding of the role of microglia in CNS physiology.

Influence of Dietary Cholesterol on Growth Performance, Fat Accumulation, and Expression of OlApoA-I with Response to Immune Stimuli in Medaka (Oryzias latipes)

Influence of Dietary Cholesterol on Growth Performance, Fat Accumulation, and Expression of OlApoA-I with Response to Immune Stimuli in Medaka (Oryzias latipes)

Photodynamic therapy stimulates IL-6 and IL-8 in responding patients with HPV infection associated or not with LSIL

Photodynamic Therapy (PDT) is a non-invasive treatment that has shown its usefulness in eliminating low grade squamous intraepithelial lesion (LSIL) and Human Papilloma Virus (HPV) infection. The response to PDT is variable, how patient´s immunology works during human PDT is unclear and therefore, the main of this work was to characterize the local immune response during treatment with PDT in patients with LSIL and / or persistent HPV infection. Two groups divided into Complete Response and Non Response patients to PDT, which were treated with a scheme of 12% δ-aminolevulinic acid (ALA), 2 irradiations 48 h apart at a total energy dose of 200 J/cm2, their local immune response were analyzed by Cytometric Bead Array (CBA) and spectral Cytometry before and after each irradiation. Cytokine mostly expressed previously PDT was IL-8 in all groups. PDT stimulates the increase in IL-6 and IL-8 concentrations at 48 h, being greater in the group of responding patients as well as IL-6 and IL-10 proving the host immune stimulus to remit diagnosis. Complete Response group has a higher percentage of total CD45+ cells before treatment than Non Response. A decrement pattern of CD8+ were observed on Non Response group during treatment. An increase tendency was observed on CD14+ and HLADR-ABC+ cells in both response groups. PDT is able to stimulate immune response, being important to treatment effectiveness increasing innate immune cells and their activation, such as monocytes, cytotoxic lymphocytes. A multiple HPV infection could be related to a less expression of cytokines during PDT.

Measurement of anti SARS-CoV-2 RBD IgG in saliva: validation of a highly sensitive assay and effects of the sampling collection method and correction by protein.

To develop and evaluate a new highly sensitive assay to detect IgG anti-SARS-CoV-2 RBD in saliva samples. A two-step sandwich type immunoassay based on the amplified luminescent proximity homogeneous technology was developed and an analytical validation was performed. As a part of this validation, the influence of factors, such as different sampling conditions (stimulated saliva and passive drool) and the correction of values by total protein content, in the ability of saliva to detect increases in antibodies after an immune stimulus and be an alternative to serum, was evaluated. For this purpose, paired samples of saliva and serum at different times after vaccination were used. Saliva concentrations were lower than serum, but both fluids showed similar kinetics, with higher correlations when saliva was obtained by passive flow and the results were not corrected by protein. The developed method showed a good analytical performance and can properly measure antibody concentrations in saliva of vaccinated individuals. However, saliva could have a lower sensitivity compared to serum at initial stages of the immune response and also when the antibody response decreased after a stimulus.

P337: LONG TERM INFECTION-DRIVES CHANGES IN THE BONE MARROW MICRO-ENVIRONMENT OF PAX5+/- MICE PREDISPOSED TO B CELL PRECURSOR ACUTE LYMPHOBLASTIC LEUKEMIA

Background: Pax5 heterozygosity (Pax5+/-) in mice mimics germline or somatic Pax5 dysregulation (resulting in reduced Pax5 levels) observed in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL). While a link between general non-specific infectious exposure and BCP-ALL has been demonstrated in the Pax5+/- mouse model, the effects of a specifically tractable infection are poorly understood. In particular, little is known about potential interactions of pre-leukemic early progenitor B cell populations and immune cells present in the bone marrow microenvironment (BME) during an infection. Aims: We aimed to characterize the short-term and long-term effects of a viral infection in the BME of the Pax5+/- mouse model employing the Lymphocytic choriomeningitis virus (LCMV). LCMV is a non-cytopathic virus that has been extensively utilized to investigate virus-induced immunopathology, effector responses and immune tolerance. Methods:Pax5+/- mice backcrossed to the C57BL/6J background (N10) were infected with LCMV. Using flow cytometry, ELISA and plaque assay, innate and late adaptive immune responses in infected Pax5+/- and WT (Pax5+/+) were assessed. Pre-leukemic early progenitor B cell populations, antigen-specific CD8+ T cells and regulatory T cells (Treg) were evaluated in the BME. This was complemented by short-term ex vivo assays where B cells were stimulated with differing immune stimuli. Results: When we investigated immune responses in a short-term ex vivo culture system using the bone marrow of Pax5-/+ and WT mice, we found differences in the induction of the interleukin 7 receptor (IL-7r) on immature Pro-B cells as well as the production of cytokines (IL-6 and TNF-▫▫) in response to the toll-like receptor (TLR7) agonist R848 and the lymphocytic choriomeningitis virus (LCMV) Docile strain. When we infected Pax5-/+ and WT mice with LCMV-Docile, we found that innate (early interferon production) and adaptive immune responses (tetramer positive CD8+ T cells and early viral titers) were not intrinsically impaired in Pax5-/+ mice. However, at day 90 post-infection, LCMV-specific T cells were present within the BME and tetramer specific CD8+ T cells raised against the LCMV nucleocapsid protein (np 396) were increased in the BM of Pax5-/+ infected mice (Figure 1A). Furthermore, when we evaluated Major Histocompatibility Complex Class II (MHC-II) expression on different B cell subsets in the BME of infected and uninfected mice, we found that there was a significant upregulation in all immature B-cell subsets (Pro-B, PreBI-II) in response to infection in the WT but not in the Pax5-/+ infected mice. Pax5-/+ mice were susceptible to LCMV infection resulting in shorter long-term survival compared to infected WT mice (Figure 1B). Image:Summary/Conclusion: This study demonstrates that the BME environment as well as survival of pre-leukemic Pax5-/+ mice is differently affected by LCMV infection supporting the observations that immune dysregulation could contribute to the emergence of the leukemic clone1. 1Supported by the Carreras foundation project no. DJCLS07R/2019

Impact of gut microenvironment on epigenetic signatures of intestinal T helper cell subsets

The intestine, which is constantly exposed to an extensive range of antigens and immune stimuli, harbours a large number of highly diverse CD4+ T helper (Th) cells. Maintaining a balance between pro-inflammatory and tolerogenic intestinal Th cell subsets is crucial for the homeostasis and functionality of the gastrointestinal tract. Recent evidence suggests that epigenetic mechanisms play a vital role for Th cell differentiation and specialization, and dysregulation of these epigenetic regulations can result in an imbalance of Th cell subsets, causing the onset and progression of intestinal inflammatory diseases. Furthermore, epigenetic alterations might be orchestrated through microbiota-derived metabolites, which can function as epigenetic modifiers by catalyzing major enzymes involved in epigenetic modifications. In this review, we focus on the epigenetic control of Th cell differentiation and functional specialization in intestinal tissues in health and disease, and also discuss the role of microbiota in shaping intestinal Th cell epigenomes.

Generation of vascularized brain organoids to study neurovascular interactions.

Brain organoids have been used to recapitulate the processes of brain development and related diseases. However, the lack of vasculatures, which regulate neurogenesis and brain disorders, limits the utility of brain organoids. In this study, we induced vessel and brain organoids, respectively, and then fused two types of organoids together to obtain vascularized brain organoids. The fused brain organoids were engrafted with robust vascular network-like structures and exhibited increased number of neural progenitors, in line with the possibility that vessels regulate neural development. Fusion organoids also contained functional blood-brain barrier-like structures, as well as microglial cells, a specific population of immune cells in the brain. The incorporated microglia responded actively to immune stimuli to the fused brain organoids and showed ability of engulfing synapses. Thus, the fusion organoids established in this study allow modeling interactions between the neuronal and non-neuronal components in vitro, particularly the vasculature and microglia niche.

Variation of Immune Cell Responses in Humans Reveals Sex-Specific Coordinated Signaling Across Cell Types.

Assessing the health and competence of the immune system is central to evaluating vaccination responses, autoimmune conditions, cancer prognosis, and treatment. With an increasing number of studies examining immune dysregulation, there is a growing need for a curated reference of variation in immune parameters in healthy individuals. We used mass cytometry (CyTOF) to profile blood from 86 humans in response to 15 ex vivo immune stimuli. We present reference ranges for cell-specific immune markers and highlight differences that appear across sex and age. We identified modules of immune features that suggest there exists an underlying structure to the immune system based on signaling pathway responses across cell types. We observed increased MAPK signaling in inflammatory pathways in innate immune cells and greater overall coordination of immune cell responses in females. In contrast, males exhibited stronger pSTAT1 and pTBK1 responses. These reference data are publicly available as a resource for immune profiling studies.

The Induced Immune Response in Patients With Infectious Spondylodiscitis: A Prospective Observational Cohort Study.

IntroductionInfectious spondylodiscitis is a rare infection of the intervertebral disc and the adjacent vertebral bodies that often disseminates and requires long-term antibiotic therapy. Immunologic profiling of patients with infectious spondylodiscitis could allow for a personalized medicine strategy. We aimed to examine the induced immune response in patients with infectious spondylodiscitis during and after antibiotic therapy. Furthermore, we explored potential differences in the induced immune response depending on the causative pathogen and the dissemination of the disease.MethodsThis was a prospective observational cohort study that enrolled patients with infectious spondylodiscitis between February 2018 and August 2020. A blood sample was collected at baseline, after four to six weeks of antibiotic therapy (during antibiotic therapy), and three to seven months after end of antibiotic therapy (post-infection). The induced immune response was assessed using the standardized functional immune assay TruCulture®. We used a panel of three immune cell stimuli (lipopolysaccharide, Resiquimod and polyinosinic:polycytodylic acid) and an unstimulated control. For each stimulus, the induced immune response was assessed by measuring the released concentration of Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p40, IL-17A, Interferon-γ (IFN-γ) and Tumor necrosis factor-α (TNF-α) in pg/mL.ResultsIn total, 49 patients with infectious spondylodiscitis were included. The induced immune responses were generally lower than references at baseline, but the cytokine release increased in patients after treatment with antibiotic therapy. Post-infection, most of the released cytokine concentrations were within the reference range. No significant differences in the induced immune responses based on stratification according to the causative pathogen or dissemination of disease were found.ConclusionWe found lower induced immune responses in patients with infectious spondylodiscitis at baseline. However, post-infection, the immune function normalized, indicating that an underlying immune deficiency is not a prominent factor for spondylodiscitis. We did not find evidence to support the use of induced immune responses as a tool for prediction of the causative pathogen or disease dissemination, and other methods should be explored to guide optimal treatment of patients with infectious spondylodiscitis.

Response of Human Liver Tissue to Innate Immune Stimuli.

Precision-cut human liver slice cultures (PCLS) have become an important alternative immunological platform in preclinical testing. To further evaluate the capacity of PCLS, we investigated the innate immune response to TLR3 agonist (poly-I:C) and TLR4 agonist (LPS) using normal and diseased liver tissue. Pathological liver tissue was obtained from patients with active chronic HCV infection, and patients with former chronic HCV infection cured by recent Direct-Acting Antiviral (DAA) drug therapy. We found that hepatic innate immunity in response to TLR3 and TLR4 agonists was not suppressed but enhanced in the HCV-infected tissue, compared with the healthy controls. Furthermore, despite recent HCV elimination, DAA-cured liver tissue manifested ongoing abnormalities in liver immunity: sustained abnormal immune gene expression in DAA-cured samples was identified in direct ex vivo measurements and in TLR3 and TLR4 stimulation assays. Genes that were up-regulated in chronic HCV-infected liver tissue were mostly characteristic of the non-parenchymal cell compartment. These results demonstrated the utility of PCLS in studying both liver pathology and innate immunity.

Context-dependent induction of autoimmunity by TNF signaling deficiency.

TNF inhibitors are widely used to treat inflammatory diseases; however, 30%–50% of treated patients develop new autoantibodies, and 0.5%–1% develop secondary autoimmune diseases, including lupus. TNF is required for formation of germinal centers (GCs), the site where high-affinity autoantibodies are often made. We found that TNF deficiency in Sle1 mice induced TH17 T cells and enhanced the production of germline encoded, T-dependent IgG anti-cardiolipin antibodies but did not induce GC formation or precipitate clinical disease. We then asked whether a second hit could restore GC formation or induce pathogenic autoimmunity in TNF-deficient mice. By using a range of immune stimuli, we found that somatically mutated autoantibodies and clinical disease can arise in the setting of TNF deficiency via extrafollicular pathways or via atypical GC-like pathways. This breach of tolerance may be due to defects in regulatory signals that modulate the negative selection of pathogenic autoreactive B cells.

A fourth dose of the mRNA-1273 SARS-CoV-2 vaccine improves serum neutralization against the Delta variant in kidney transplant recipients

A fourth dose of the mRNA-1273 SARS-CoV-2 vaccine improves serum neutralization against the Delta variant in kidney transplant recipients

Transgenerational Effects of Maternal Immune Activation on Specific Antibody Responses in Layer Chickens.

Activation of the maternal immune system may affect innate and adaptive immune responses in the next generation and may therefore have implications for vaccine efficacy and dietary immune modulation by feed additives. However, transgenerational effects on immune responses in chickens have been investigated to a limited extend. The present study investigated effects of intratracheal (i.t) specific and aspecific immune activation of laying hens on specific antibody production in the next generation. In two experiments laying hens received intratracheally an immune stimulus with human serum albumin (HuSA) or lipopolysaccharide (LPS). In experiment 1, hatchlings of the immune activated hens were at 4 weeks i.t. immunized with HuSA or HuSA+LPS. Maternal immune activation with LPS increased HuSA specific IgY and IgM responses in offspring. These results suggest a transgenerational effect of the maternal immune system on the specific antibody response in the next generation. In experiment 2 hatchlings received either β-glucan-enriched feed or control feed and were i.t. immunized with HuSA. Maternal immune activation with LPS decreased IgY anti-HuSA responses after HuSA immunization within hatchlings that received β-glucan enriched feed. The results of Experiment 2 suggest a transgenerational link between the innate immune system of mother and specific antibody responses in offspring. Despite variabilities in the outcomes of the two experiments, the observations of both suggest a link between the maternal innate immune system and the immune system of the offspring. Furthermore, our results may imply that maternal activation of the innate immune system can influence immune modulating dietary interventions and vaccine strategies in the next generation.

Molecular characterization, expression profile, and antiviral activity of redlip mullet (Liza haematocheila) viperin.

Viperin is known to exhibit activity against RNA viral infection. Viral hemorrhagic septicemia virus (VHSV) is a negative-sense single-stranded RNA virus that causes severe loss in aquaculture species. Susceptible species include redlip mullets (Liza haematocheila), which has become an economically important euryhaline mugilid species in offshore aquaculture along the west coast of Korea. Although interferon-stimulated genes are suspected to act against VHSV, specific pathways or mechanisms of these antiviral actions in redlip mullets have not yet been established. In silico studies of the mullet viperin (Lhrsad2) revealed an S-adenosyl methionine binding conserved domain containing the 77CNYKCGFC84 sequence. In the tissue distribution, the highest levels of lhrsad2 expression were observed in the blood. When injected with poly(I:C), an approximately 17-fold upregulation (compared to the control) of viperin was detected in the blood after 24h. Furthermore, non-viral immune stimuli, including Lactococcus garvieae (L. garvieae) and lipopolysaccharide (LPS), that were injected into redlip mullets were not found to induce considerable levels of viperin expression. Subcellular analysis revealed that Lhrsad2 localized to the endoplasmic reticulum (ER). To investigate Lhrsad2's antiviral effects against VHSV, cells overexpressing lhrsad2 were infected with VHSV, and then the viral titer and viral gene expression were analyzed. Both assays revealed the potential of Lhrsad2 to significantly reduce VHSV transcription and replication. In brief, the current study illustrates the remarkable ability of viperin to weaken VHSV in redlip mullet.

Clinical and Translational Significance of Basophils in Patients with Cancer.

Despite comprising a very small proportion of circulating blood leukocytes, basophils are potent immune effector cells. The high-affinity receptor for IgE (FcɛRI) is expressed on the basophil cell surface and powerful inflammatory mediators such as histamine, granzyme B, and cytokines are stored in dense cytoplasmic granules, ready to be secreted in response to a range of immune stimuli. Basophils play key roles in eliciting potent effector functions in allergic diseases and type 1 hypersensitivity. Beyond allergies, basophils can be recruited to tissues in chronic and autoimmune inflammation, and in response to parasitic, bacterial, and viral infections. While their activation states and functions can be influenced by Th2-biased inflammatory signals, which are also known features of several tumor types, basophils have received little attention in cancer. Here, we discuss the presence and functional significance of basophils in the circulation of cancer patients and in the tumor microenvironment (TME). Interrogating publicly available datasets, we conduct gene expression analyses to explore basophil signatures and associations with clinical outcomes in several cancers. Furthermore, we assess how basophils can be harnessed to predict hypersensitivity to cancer treatments and to monitor the desensitization of patients to oncology drugs, using assays such as the basophil activation test (BAT).

TRPV4: Cell type-specific activation, regulation and function in the vertebrate eye.

The architecture of the vertebrate eye is optimized for efficient delivery and transduction of photons and processing of signaling cascades downstream from phototransduction. The cornea, lens, retina, vasculature, ciliary body, ciliary muscle, iris and sclera have specialized functions in ocular protection, transparency, accommodation, fluid regulation, metabolism and inflammatory signaling, which are required to enable function of the retina-light sensitive tissue in the posterior eye that transmits visual signals to relay centers in the midbrain. This process can be profoundly impacted by non-visual stimuli such as mechanical (tension, compression, shear), thermal, nociceptive, immune and chemical stimuli, which target these eye regions to induce pain and precipitate vision loss in glaucoma, diabetic retinopathy, retinal dystrophies, retinal detachment, cataract, corneal dysfunction, ocular trauma and dry eye disease. TRPV4, a polymodal nonselective cation channel, integrate non-visual inputs with homeostatic and signaling functions of the eye. The TRPV4 gene is expressed in most if not all ocular tissues, which vary widely with respect to the mechanisms of TRPV4 channel activation, modulation, oligomerization, and participation in protein- and lipid interactions. Under- and overactivation of TRPV4 may affect intraocular pressure, maintenance of blood-retina barriers, lens accommodation, neuronal function and neuroinflammation. Because TRPV4 dysregulation precipitates many pathologies across the anterior and posterior eye, the channel could be targeted to mitigate vision loss.

Inhibition of African swine fever virus replication by β-glucan.

African swine fever (ASF) is one of the most important diseases in pigs because of its effects on all ages and breeds. To date, commercial vaccines and drugs for the prevention of ASF are lacking in the market and the survival of African swine fever virus (ASFV) in various environmental, farm, and or feed matrices has allowed the virus to remain, causing new outbreaks in the pig population. Besides biosecurity and animal husbandry management practices, the improvement of the host immune responses is critical to control, managing, and preventing ASF. In this study, we investigated the protective role of β-glucan against ASFV infection using a porcine alveolar macrophage (PAM) model. The effects of β-glucan on cell proliferation were evaluated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The potential effects of β-glucan against a field ASFV strain isolated in Vietnam were further examined by real-time PCR and hemadsorption assays. The interferon (IFN)-α and interleukin (IL)-6 protein production induced by β-glucan was determined using a sandwich enzyme-linked immunosorbent assay. Our results demonstrated that the β-glucan additive possessed an immune stimulus factor against ASFV. Specifically, protection of PAMs against ASFV infection in vitro was observed at 12 hours (p < 0.05) at the tested doses (30 and 50 µg/ml) as induced by incubation with β-glucan for 2 hours. These effects remained until 24 hours after post-infection. Additionally, at a high dose (50 µg/ml), pre-treatment with the β-glucan statistically increased the expression levels of IFNα and IL-6 when compared to untreated groups or only ASFV infection. Together, these findings indicated that the β-glucan may protect the host against ASFV infection via the multiple cellular immune mechanisms.

Periodontal health, neutrophil activity and cardiovascular health in captive chimpanzees

ObjectiveTo investigate the association of dental and cardiac disease in a cohort of captive chimpanzees Design12 captive chimpanzees underwent periodontal and cardiac examinations under anaesthesia during a relocation to a new enclosure. Blood samples were taken for analysis of circulating markers of cardiac health, nutritional status and isolation of neutrophils for functional assays. They were then observed for three years for signs of heart disease. ResultsAlthough the chimpanzees displayed large quantities of supragingival plaque, they had low bleeding scores. Peripheral blood neutrophils responded to innate and adaptive immune stimuli. In the follow up period two animals died and post mortem confirmed heart disease. Levels of NT-proBNP were found to be high in chimpanzees that died from heart disease. ConclusionsWhilst there appeared to be a correlation between probing depth and age, there appeared to be no correlation between dental data and heart data in this cohort.