Late Immune Response Research Articles

The Human Pathogen Mycobacterium tuberculosis and the Fish Pathogen Mycobacterium marinum Trigger a Core Set of Late Innate Immune Response Genes in Zebrafish Larvae.

Zebrafish is a natural host of various Mycobacterium species and a surrogate model organism for tuberculosis research. Mycobacterium marinum is evolutionarily one of the closest non-tuberculous species related to M. tuberculosis and shares the majority of virulence genes. Although zebrafish is not a natural host of the human pathogen, we have previously demonstrated successful robotic infection of zebrafish embryos with M. tuberculosis and performed drug treatment of the infected larvae. In the present study, we examined for how long M. tuberculosis can be propagated in zebrafish larvae and tested a time series of infected larvae to study the transcriptional response via Illumina RNA deep sequencing (RNAseq). Bacterial aggregates carrying fluorescently labeled M. tuberculosis could be detected up to 9 days post-infection. The infected larvae showed a clear and specific transcriptional immune response with a high similarity to the inflammatory response of zebrafish larvae infected with the surrogate species M. marinum. We conclude that M. tuberculosis can be propagated in zebrafish larvae for at least one week after infection and provide further evidence that M. marinum is a good surrogate model for M. tuberculosis. The generated extensive transcriptome data sets will be of great use to add translational value to zebrafish as a model for infection of tuberculosis using the M. marinum infection system. In addition, we identify new marker genes such as dusp8 and CD180 that are induced by M. tuberculosis infection in zebrafish and in human macrophages at later stages of infection that can be further investigated.

Severe Allergy as a Chronic Inflammatory Condition From a Systems Biology Perspective.

Persistent and unresolved inflammation is a common underlying factor observed in several and seemingly unrelated human diseases, including cardiovascular and neurodegenerative diseases. Particularly, in atopic conditions, acute inflammatory responses such as those triggered by insect venom, food or drug allergies possess also a life-threatening potential. However, respiratory allergies predominantly exhibit late immune responses associated with chronic inflammation, that can eventually progress into a severe phenotype displaying similar features as those observed in other chronic inflammatory diseases, as is the case of uncontrolled severe asthma. This review aims to explore the different facets and systems involved in chronic allergic inflammation, including processes such as tissue remodelling and immune cell dysregulation, as well as genetic, metabolic and microbiota alterations, which are common to other inflammatory conditions. Our goal here was to deepen on the understanding of an entangled disease as is chronic allergic inflammation and expose potential avenues for the development of better diagnostic and intervention strategies.

Osseointegrative and immunomodulative 3D-Printing Ti6Al4V-based implants embedded with biogenic hydroxyapatite

Although titanium-based metal implants have become a game changer in dental and orthopedic therapies, they still have several problems such as late osseointegration and immune response. In this study, we present a novel strategy to develop Ti6Al4V-based implants embedded with biogenic hydroxyapatite derived from equine bone to overcome these problems. A selective laser melting technique was employed for facile fabrication with flexible fusing feedstock and regular uniform distribution of equine bone. The physicochemical characteristics, cell attachment and proliferation, osteogenic differentiation, osseointegration, inflammatory response, and metabolomics of the developed Ti6Al4V/equine bone composite were then investigated. The Ti6Al4V-based composite integrated with equine bone at a certain concentration has improved the crystalline structure (β-Ti) suitable for implantation and exhibited higher hydrophilicity and protein adsorption. They significantly promoted cell attachment, osteogenic differentiation, and anti-inflammatory effects in vitro. In vivo study confirmed the osseointegration and alleviated inflammatory responses. Furthermore, the Ti6Al4V-based implants integrated with equine bone significantly reduced metabolites associated with inflammatory responses both in vitro and in vivo. The observed reduction in inflammatory responses suggests a subsequent promotion of osteogenesis. These promising results position the Ti6Al4V-based implant integrated with equine bone as a potential candidate for replacing conventional dental and orthopedic implants.

Cutting edge of immune response and immunosuppressants in allogeneic and xenogeneic islet transplantation.

As an effective treatment for diabetes, islet transplantation has garnered significant attention and research in recent years. However, immune rejection and the toxicity of immunosuppressive drugs remain critical factors influencing the success of islet transplantation. While immunosuppressants are essential in reducing immune rejection reactions and can significantly improve the survival rate of islet transplants, improper use of these drugs can markedly increase mortality rates following transplantation. Additionally, the current availability of islet organ donations fails to meet the demand for organ transplants, making xenotransplantation a crucial method for addressing organ shortages. This review will cover the following three aspects: 1) the immune responses occurring during allogeneic islet transplantation, including three stages: inflammation and IBMIR, allogeneic immune response, and autoimmune recurrence; 2) commonly used immunosuppressants in allogeneic islet transplantation, including calcineurin inhibitors (Cyclosporine A, Tacrolimus), mycophenolate mofetil, glucocorticoids, and Bortezomib; and 3) early and late immune responses in xenogeneic islet transplantation and the immune effects of triple therapy (ECDI-fixed donor spleen cells (ECDI-SP) + anti-CD20 + Sirolimus) on xenotransplantation.

Distinct defects in early innate and late adaptive immune responses typify impaired fracture healing in diet-induced obesity.

Bone fractures, the most common musculoskeletal injuries, heal through three main phases: inflammatory, repair, and remodeling. Around 10% of fracture patients suffer from impaired healing that requires surgical intervention, a huge burden on the healthcare system. The rate of impaired healing increases with metabolic diseases such as obesity-associated hyperglycemia/type 2 diabetes (T2D), an increasing concern given the growing incidence of obesity/T2D. Immune cells play pivotal roles in fracture healing, and obesity/T2D is associated with defective immune-cell functions. However, there is a gap in knowledge regarding the stoichiometry of immune cells that populate the callus and how that population changes during different phases of healing. Here, we used complementary global and single-cell techniques to characterize the repertoire of immune cells in the fracture callus and to identify populations specifically enriched in the fracture callus relative to the unfractured bone or bone marrow. Our analyses identified two clear waves of immune-cell infiltration into the callus: the first wave occurs during the early inflammatory phase of fracture healing, while the second takes place during the late repair/early remodeling phase, which is consistent with previous publications. Comprehensive analysis of each wave revealed that innate immune cells were activated during the early inflammatory phase, but in later phases they returned to homeostatic numbers and activation levels. Of the innate immune cells, distinct subsets of activated dendritic cells were particularly enriched in the inflammatory healing hematoma. In contrast to innate cells, lymphocytes, including B and T cells, were enriched and activated in the callus primarily during the late repair phase. The Diet-Induced Obesity (DIO) mouse, an established model of obesity-associated hyperglycemia and insulin resistance, suffers from multiple healing defects. Our data demonstrate that DIO mice exhibit dysregulated innate immune responses during the inflammatory phase, and defects in all lymphocyte compartments during the late repair phase. Taken together, our data characterize, for the first time, immune populations that are enriched/activated in the callus during two distinct phases of fracture healing and identify defects in the healing-associated immune response in DIO mice, which will facilitate future development of immunomodulatory therapeutics for impaired fracture healing.

Hormonal, immune, and oxidative stress responses to blood flow-restricted exercise.

Heavy-load free-flow resistance exercise (HL-FFRE) is a widely used training modality. Recently, low-load blood-flow restricted resistance exercise (LL-BFRRE) has gained attention in both athletic and clinical settings as an alternative when conventional HL-FFRE is contraindicated or not tolerated. LL-BFRRE has been shown to result in physiological adaptations in muscle and connective tissue that are comparable to those induced by HL-FFRE. The underlying mechanisms remain unclear; however, evidence suggests that LL-BFRRE involves elevated metabolic stress compared to conventional free-flow resistance exercise (FFRE). The aim was to evaluate the initial (<10 min post-exercise), intermediate (10-20 min), and late (>30 min) hormonal, immune, and oxidative stress responses observed following acute sessions of LL-BFRRE compared to FFRE in healthy adults. A systematic literature search of randomized and non-randomized studies was conducted in PubMed, Embase, Cochrane Central, CINAHL, and SPORTDiscus. The Cochrane Risk of Bias (RoB2, ROBINS-1) and TESTEX were used to evaluate risk of bias and study quality. Data extractions were based on mean change within groups. A total of 12525 hits were identified, of which 29 articles were included. LL-BFRRE demonstrated greater acute increases in growth hormone responses when compared to overall FFRE at intermediate (SMD 2.04; 95% CI 0.87, 3.22) and late (SMD 2.64; 95% CI 1.13, 4.16) post-exercise phases. LL-BFRRE also demonstrated greater increase in testosterone responses compared to late LL-FFRE. These results indicate that LL-BFRRE can induce increased or similar hormone and immune responses compared to LL-FFRE and HL-FFRE along with attenuated oxidative stress responses compared to HL-FFRE.

Identification of Potential Novel B-Cell Epitopes of Capsid Protein VP2 in Senecavirus A.

Senecavirus A (SVA) is a type of nonenveloped single-stranded, positive-sense RNA virus. The VP2 protein is a structural protein that plays an important role in inducing early and late immune responses of the host. However, its antigenic epitopes have not been fully elucidated. Therefore, defining the B epitopes of the VP2 protein is of great importance to revealing its antigenic characterization. In this study, we analyzed B-cell immunodominant epitopes (IDEs) of the VP2 protein from the SVA strain CH/FJ/2017 using the Pepscan approach and a bioinformatics-based computational prediction method. The following four novel IDEs of VP2 were identified: IDE1, 41TKSDPPSSSTDQPTTT56; IDE2, 145PDGKAKSLQELNEEQW160; IDE3, 161VEMSDDYRTGKNMPF175; and IDE4, 267PYFNGLRNRFTTGT280. Most of the IDEs were highly conserved among the different strains. To our knowledge, the VP2 protein is a major protective antigen of SVA that can induce neutralizing antibodies in animals. Here, we analyzed the immunogenicity and neutralization activity of four IDEs of VP2. Consequently, all four IDEs showed good immunogenicity that could elicit specific antibodies in guinea pigs. A neutralization test in vitro showed that the peptide-specific guinea pig antisera of IDE2 could neutralize SVA strain CH/FJ/2017, and IDE2 was identified as a novel potential neutralizing linear epitope. This is the first time VP2 IDEs have been identified by using the Pepscan method and a bioinformatics-based computational prediction method. These results will help elucidate the antigenic epitopes of VP2 and clarify the basis for immune responses against SVA. IMPORTANCE The clinical symptoms and lesions caused by SVA are indistinguishable from those of other vesicular diseases in pigs. SVA has been associated with recent outbreaks of vesicular disease and epidemic transient neonatal losses in several swine-producing countries. Due to the continuing spread of SVA and the lack of commercial vaccines, the development of improved control strategies is urgently needed. The VP2 protein is a crucial antigen on the capsids of SVA particles. Furthermore, the latest research showed that VP2 could be a promising candidate for the development of novel vaccines and diagnostic tools. Hence, a detailed exploration of epitopes in the VP2 protein is necessary. In this study, four novel B-cell IDEs were identified using two different antisera with two different methods. IDE2 was identified as a new neutralizing linear epitope. Our findings will help in the rational design of epitope vaccines and further understanding of the antigenic structure of VP2.

Kinetics of humoral immune response and severity of infection after three doses of SARS-CoV-2 mRNA vaccine in a large cohort of kidney transplant recipients

BackgroundCOVID-19 in kidney transplant recipients is associated with high morbidity and mortality. In this study we aimed to evaluate: (i) the seroconversion rate after BNT162b2 (Pfizer-BioNTech) SARS-CoV-2 vaccine, (ii) factors associated with humoral response, (iii) clinical outcome of COVID-19 in kidney transplanted patients.MethodsWe enrolled a cohort of 743 kidney transplant recipients followed up from March 2020 until April 2022. A subset of 336 patients, who received three-doses of SARS-CoV-2 vaccine, was analyzed in terms of kinetics of humoral immune response and compared to a control group of 94 healthcare workers. Antibody response was tested before vaccination (T0), 15 and 90 days after the second dose (T1 and T2), on the day of the third dose (T3) and one month after the third dose (T4).ResultsWe observed that 66 out of 743 subjects had COVID-19 infection pre-vaccination: 65.2% had severe symptoms, 27.3% were hospitalized (9 deaths), none were asymptomatic. After three doses, 51 patients had COVID-19 infection, 60.8% were asymptomatic, 27.5% reported mild symptoms, 3.9% showed severe symptoms, 7.8% were hospitalized (2 deaths).In the subset of 336 vaccinated patients, an antibody level > 0.8 U/ml was detected at T1, that increased at T2 and T3, peaking at T4. Independent factors associated with a negative antibody titer at T4 were decreasing estimated glomerular filtration rate, time from transplantation, and antimetabolites (all p < 0.001) and age (p = 0.007).ConclusionsThe kinetics of humoral response after three doses of vaccine in kidney transplant patients is characterized by a late but effective immune response against SARS-CoV-2, reducing morbidity and mortality.Graphical abstract

What explains the poor contraction of the viral load during paediatric HIV infection?

An acute HIV infection in young children differs markedly from that in adults: Children have higher viral loads (VL), and a poor contraction to a setpoint VL that is not much lower than the peak VL. As a result, children progress faster towards AIDS in the absence of treatment. We used a classical ordinary differential equation model for viral infection dynamics to study why children have a lower viral contraction ratio than adults. We performed parameter sweeps to identify factors explaining the observed difference between children and adults. We grouped parameters associated with the host, the infection, or the immune response. Based on paediatric data available from datasets within the EPIICAL project (https://www.epiical.org/), we refuted that viral replication rates differ between young children and adults, and therefore these cannot be responsible for the low VL contraction ratios seen in children. The major differences in lowering VL contraction ratio resulted from sweeping the parameters linked to the immune response. Thus, we postulate that an ”ineffective” (late and/or weak) immune response is the most parsimonious explanation for the higher setpoint VL in young children, and hence the reason for their fast disease progression.

Influence of polymorphic variations of IFNL, HLA, and IL-6 genes in severe cases of COVID-19.

The administration of vaccination doses to the global population has led to a decrease in the incidence of COVID-19. However, the clinical picture developed by infected individuals remains extremely concerning due to the great variability in the severity of cases even in vaccinated individuals. The clinical progression of the pathology is characterized by various influential factors such as sex, age group, comorbidities, and the genetics of the individual. The immune response to viral infections can be strongly influenced by the genetics of individuals; nucleotide variations called single-nucleotide polymorphisms (SNPs) in structures involved in the innate and adaptive immune response such as interferon (IFN)-λ, human leukocyte antigen (HLA), and interleukin (IL)-6 are frequently associated with pathological progression. In this study, we conducted a review of the main SNPs of these structures that are associated with severity in COVID-19. Searches were conducted on some platforms of the National Center for Biotechnology and Information (NCBI), and 102 studies were selected for full reading according to the inclusion criteria. IFNs showed a strong association with antiviral function, specifically, IFN-λ3 (IL-28B) demonstrated genetic variants commonly related to clinical progression in various pathologies. For COVID-19, rs12979860 and rs1298275 presented frequently described unfavorable genotypes for pathological conditions of hepatitis C and hepatocellular carcinoma. The high genetic variability of HLA was reported in the studies as a crucial factor relevant to the late immune response, mainly due to its ability to recognize antigens, with the HLA-B*46:01 SNP being associated with susceptibility to COVID-19. For IL-6, rs1554606 showed a strong relationship with the clinical progression of COVID-19. In addition, rs2069837 was identified with possible host protection relationships when linked to this infection.

Eosinophils Recruited during Pulmonary Vaccination Regulate Mucosal Antibody Production.

Eosinophils have been previously shown to be able to regulate early humoral responses during systemic vaccination. Here we investigated the role of eosinophils during pulmonary vaccination, comparing vaccine-induced responses in eosinophil-deficient (ΔdblGATA) and wild-type mice using a Th2 adjuvant. We observed that eosinophils were needed to induce a complete vaccine response, thereby eliciting specific antibody-secreting plasma cells in the regional lymph nodes and antibody secretion in the BAL at the early stage of the immune response. Reintroduction of eosinophils in the lungs of ΔdblGATA mice during the priming stage enhanced both specific IgM and IgG plasma cells but not specific IgA plasma cells. Upon vaccination, eosinophils migrated to the lungs and secreted cytokines involved in B-cell activation, which might promote antibody production. Importantly, however, the absence of eosinophils did not impair late immune responses in a prime/boost protocol because, in that setup, we uncovered a compensating mechanism involving a Th17 pathway. In conclusion, our data demonstrate for the first time a new role for eosinophils during lung mucosal vaccination, whereby they accelerate early immune responses (IgM and IgG) while regulating IgA production at the late stages.

Evaluation of AGP, SSA concentration with the relationship of antibody titer in broiler chicken vaccinated with IBD virus

Gumboro or Infectious bursal disease (IBD) is one of the most important diseases in poultry industry. IBD causes economic losses as a result to mortality and reduction in performance and medicine expenses(de S. B. Fróes et al., 2018). IBD is Severe acute disease of 3-6-week-old birds is associated with high mortality, but a less acute or subclinical disease is common in 0-3-week-old birds (Sali, 2019). IBD virus causes lymphoid depletion of the bursa and if this occurs in the first 2 weeks of life, significant depression of the humoral antibody response may result. The current study aims to measurement of antibody titer and acute phase proteins (AGP and SSA) in broiler chickens subjected to the Gumboro vaccine to explore the intensity of the vaccine strain and the response of both the early innate immune response and late humoral immune responses (antibody titers) raised against the vaccine. A handed Ross 308 chicks were divided into three groups, control, intermediate and intermediate plus vaccine. At 10 days old, the chicks were vaccinated and then blood samples collected at 12, 24 hours, and 10 and 15 days.

Irradiation Consequences from Chromosome Damages to Triggering of Diverse Immunological Responses

Present work was designed to investigate DNA damages post irradiation via cytokinesis-block micronucleus (CBMN) test and its corresponding immunological response. Determination of interferon- α, β for innate, interferon-γ for acquired response, TNF- α and immunoglobulin concentration IgG &amp; IgM. Six human blood samples were divided into 4 groups (control &amp; 3irradiated) which exposed to doses (0.5 - 2 and 4 Gy). Triplet blood samples (control and irradiated groups) were cultured for 72 hours after 1 hour of irradiation. γ - Irradiation induced significant increase of IFN-α (innate immunology hallmark) in all experimental doses (0.5 -2.0 and 4.0 Gy). IFN-β also recorded significant increase with control at dose 4.0 Gy. The results showed significant increase in IFN-γ representing acquired immune response at 2.0 and 4.0 Gy. These results confirmed by exhibits increase in the level of IgG and IgM production. TNF-α late immune response started to give significant increase at 2.0 and 4.0 Gy. TNF-α and IFN-β recorded significant difference when compared with control at 1.0 and 4Gy exposure also 4Gy group recorded significant increase compared with 1.0 Gy exposure. INF-α recorded significant increase at all doses when compared with control and each other. IFN-γ recorded significant increase in 1.0 and 4.0 Gy when compared with control with no significant difference between them. We conclude that immune system can sense when cells damaged. Mni which come from a variety of sources such as irradiation can lead to an immune response similar to that observed during viral infection.

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

Plant elicitor peptide 1 fortifies root cell walls and triggers a systemic root-to-shoot immune signaling in Arabidopsis

ABSTRACT Plant immunity is initiated by cell surface-localized receptors upon perception of pathogen-derived microbe or pathogen-associated molecular patterns (MAMPs/PAMPs), damage/danger-associated molecular patterns (DAMPs), and phytocytokines. Different patterns activate highly overlapping immune signaling at the early stage but divergent physiological responses at the late stage. Here, we indicate that plant elicitor peptide 1 (Pep1), a well-known DAMP, induces lignin and callose depositions, two types of late immune responses for strengthening the plant cell wall. Pep1-induced lignin and callose depositions in Arabidopsis root rely on early signaling components for Pep1 perception and signaling propagation. The phytohormone jasmonic acid and ethylene differently regulate the Pep1-regulated cell wall consolidation. Pep1 application in root also triggers a systemic immune signaling in shoot, and reactive oxygen species (ROS) is essential for the signaling communication between root and shoot. Collectively, the study reveals that Pep1 strengthens cell walls in root and triggers a systemic immune signaling from root to shoot.

The Basics of Infectious Diseases

Infectious Diseases result from exposure and contact between a host (human being) and an (uninvited) guest (micro-organism). Given the fact that billions of micro-organisms are in and around us at any time, overall, infectious diseases are comparatively rare; of the millions of different microbial species, only about 300 are known to cause human diseases. Besides exposure and contact, factors on the side of the host (genetic background, environment, underlying diseases and their therapy) and on the side of the micro-organisms (pathogenicity / virulence factors) are necessary to result in an infectious disease. “Colonization” means that a micro-organism can attach on skin or mucous membrane for some time or even indefinitely but does not invade host tissue and does not cause any symptoms. Colonizers may even induce an immune response. “Infection” is defined as a micro-organism invading through skin or mucous membranes the tissue of a host, leading to no disease (“asymptomatic infection”); or symptomatic disease. It is followed by health, disability, or death. Following the infection, microorganisms may persist in the body for a long time or even for life without causing any symptoms, which is called “latent infection”. Infectious diseases may not only be due to pathogenicity factors of a micro-organism, but may also result from (i.) direct destruction of host tissues (e.g., from viral replication); (ii.) the acute host (immune-) response; and from late immune responses resulting in immune-mediated “post-infectious diseases”. Some infections may cause an immune response that is directed against host-tissue, resulting in an “autoimmune-disease”. Given the increasing number of microbes, the increasing number of exposures, and the increasing number and fraction of susceptible/predisposed humans, it is obvious that infectious diseases will increase in the future. Vaccines and vaccination may help solve this problem.

Comparison of Immunogenicity between the Proposed Pegfilgrastim Biosimilar MYL-1401H and Reference Pegfilgrastim

Introduction: Pegfilgrastim, a long-acting granulocyte colony-stimulating factor (G-CSF), is indicated for reduction of incidence of febrile neutropenia in patients with non-myeloid malignancies receiving myelosuppressive chemotherapy. Here, the immunogenicity data for MYL-1401H, a proposed biosimilar of pegfilgrastim, from the clinical studies will be presented.Methods: The efficacy, safety, and immunogenicity of MYL-1401H were investigated in 3 clinical studies, 2 in healthy volunteers (HV) and 1 in patients receiving chemotherapy. MYL-1401H-1001 was a 3-way crossover study comparing the pharmacokinetics (PK) and pharmacodynamics (PD) of a single 2-mg dose of MYL-1401H with reference pegfilgrastim (Neulasta®) sourced from both the European Union (EU) and United States (US) in HV. MYL-1401H-1002 was a parallel-group study designed to compare the immunogenicity of MYL-1401H with US-pegfilgrastim at a repeated 6-mg dose in HV. MYL-1401H-3001 was a multicenter, randomized, double-blind, parallel-group equivalence study of MYL-1401H 6 mg vs EU-pegfilgrastim 6 mg in patients with breast cancer receiving chemotherapy for 6 cycles. The primary efficacy endpoint in MYL-1401H-3001 was duration of severe neutropenia in cycle 1, defined as days with absolute neutrophil count <0.5 × 109/L. A thorough assessment of immunogenicity was conducted across the 3 studies. The antidrug antibody (ADA; Covance, Chantilly, VA) analysis was performed using a validated, sensitive, and specific analytical method on the MesoScale Discovery® Platform (Rockville, MD). Serum samples were analyzed for the presence of ADA against MYL-1401H, EU-pegfilgrastim, and US-pegfilgrastim. Samples that resulted positive in the screening assay were further evaluated in a confirmatory assay. The samples confirmed as ADA positive were titrated to elucidate relative levels of the ADA response and further evaluated for domain characterization to determine if the antibodies were specifically directed against the polyethylene glycol (PEG) or the G-CSF domain of the molecule, or both. Samples confirmed as positive for ADA were analyzed for neutralizing antibodies (NAb; CIRION BioPharma Research) using a validated cell-based assay.Results: Overall, these studies demonstrated that the PK, PD, efficacy, and safety of MYL-1401H were equivalent to reference pegfilgrastim. Across all 3 studies, the proportions of subjects who were ADA positive before dosing were similar in the MYL-1401H (30/223; 13.5%) and EU-pegfilgrastim groups (16/139; 11.5%) and were lower in the US-pegfilgrastim group (4/97; 4.1%). Most (86.0%) of the subjects with ADA had antibodies that recognized the PEG domain, which may be attributable to exposure to PEG-related compounds in the environment as well as the highly sensitive nature of the assay, which can detect very low levels of antibodies. Treatment-induced impact on immunogenicity across the 3 studies was evaluated by analyzing the postdose ADA results excluding those subjects who were ADA positive at baseline (Table). Overall, the proportions of subjects with postdose treatment-induced ADA were similar in the MYL-1401H (20/192; 10.4%) and EU-pegfilgrastim groups (17/123; 13.8%), while they were higher in the US-pegfilgrastim group (28/93; 30.1%). Although the proportion of subjects with treatment-induced ADA was higher in the US-pegfilgrastim group, in most cases, the ADA recognized only the PEG moiety, the titers were low, and the antibodies were non-neutralizing. Two subjects (1 each in the MYL-1401H and EU-pegfilgrastim groups) had antibodies against the G-CSF moiety only. Two subjects were NAb positive in the MYL-1401H group, while none were NAb positive in either reference pegfilgrastim group. There was no evidence of loss of efficacy or severe treatment-induced immune-related adverse events in ADA- or NAb-positive subjects.Conclusion: Results in HV indicate that MYL-1401H does not induce either early or late immune response and has a low immunogenic potential, similar to that of EU- and US-pegfilgrastim, after repeated administration in a sensitive population without any confounding illness or immunosuppressive medications. Similarly, the immunogenic potentials of MYL-1401H and EU-pegfilgrastim are low in patients with breast cancer. Overall, MYL-1401H has an immunogenic profile similar to that of EU-pegfilgrastim and US-pegfilgrastim. [Display omitted] DisclosuresWaller:Mylan: Consultancy, Honoraria. Ranganna:Mylan Pharmaceuticals Inc: Employment. Pennella:Mylan: Employment. Mattano:HARP Pharma Consulting, LLC: Employment. Loa:Mylan Pharmaceuticals Inc: Employment. Donnelly:Mylan Pharmaceuticals Inc: Employment. Liu:Mylan Pharmaceuticals Inc: Employment. Watson:Covance: Employment. St-Jean:CIRION BioPharma Research Inc: Employment. Chatterjee:Biocon Research Ltd: Employment. Nayak:Biocon Research Ltd: Employment. Sengupta:Biocon Research Ltd: Employment. Kothekar:Biocon Research Ltd: Employment. Barve:Mylan Pharmaceuticals Inc: Employment.

The real life performance of 7 automated anti-SARS-CoV-2 IgG and IgM/IgA immunoassays

ObjectivesThis study was aimed at providing some insights into the real-life performance of the commercial, clinically validated anti-SARS-CoV-2 antibody assays. MethodsThe residual, anonymized samples from 97 patients referred for anti-SARS-CoV-2 antibodies testing were included in the study. The initial assessment was performed with the Euroimmun ELISAs, followed by the assays provided by: NovaTec, Snibe, Vircell, Roche, Abbott and DiaSorin. The analyses of the results were performed separately for the antibodies of the early (IgM/IgA) and late (IgG) immune response. ResultsWe observed a high variability of the results obtained with the investigated immunoassays. The fully concordant results were reported for only 57 out of 97 samples tested for IgG antibodies and for 34 out of 97 samples for IgM/IgA. The highest percentage of positive results was noted for the Euroimmun and Vircell ELISAs and the lowest for Novatec ELISAs.We proposed to distinguish true and false positive results based on the sum of positive results obtained with different methods. We arbitrarily considered reference positive samples reactive in at least half of the assays. The assay that proved to correlate the best with those reference results was the Roche electrochemiluminescence immunoassay. ConclusionsThe differences observed between immunoassays targeting the early phase antibodies were much more pronounced than between IgG assays, suggesting their lower value for clinical use. Our study also showed a high percentage of plausibly false (positive or negative) results obtained with ELISAs, which suggests their inferiority to the automated immunoassays.

Prenatal disorders and congenital Zika syndrome in squirrel monkeys

During the Zika virus (ZIKV) outbreak in Brazil (2015–2016), the clinical manifestations associated with its infection were complex and included miscarriage and congenital malformations, not previously described. In this study, we evaluated the prenatal conditions of pregnant female squirrel monkeys (Saimiri collinsi) infected during different gestational thirds (GTs) and assessed all clinical aspects, diagnostic imaging, viremia and the immune response. In our study, 75% of the infected animals in the 1st GT group had significant clinical manifestations, such as miscarriage and prolonged viremia associated with a late immune response. Consequently, their neonates showed fetal neuropathology, such as cerebral hemorrhage, lissencephaly or malformations of the brain grooves, ventriculomegaly, and craniofacial malformations. Thus, our study demonstrated the relevance of pregnant squirrel monkeys as a model for the study of ZIKV infection in neonates due to the broad clinical manifestations presented, including the typical congenital Zika syndrome manifestations described in humans.

Immune Response to Tick-Borne Hemoparasites: Host Adaptive Immune Response Mechanisms as Potential Targets for Therapies and Vaccines.

Tick-transmitted pathogens cause infectious diseases in both humans and animals. Different types of adaptive immune mechanisms could be induced in hosts by these microorganisms, triggered either directly by pathogen antigens or indirectly through soluble factors, such as cytokines and/or chemokines, secreted by host cells as response. Adaptive immunity effectors, such as antibody secretion and cytotoxic and/or T helper cell responses, are mainly involved in the late and long-lasting protective immune response. Proteins and/or epitopes derived from pathogens and tick vectors have been isolated and characterized for the immune response induced in different hosts. This review was focused on the interactions between tick-borne pathogenic hemoparasites and different host effector mechanisms of T- and/or B cell-mediated adaptive immunity, describing the efforts to define immunodominant proteins or epitopes for vaccine development and/or immunotherapeutic purposes. A better understanding of these mechanisms of host immunity could lead to the assessment of possible new immunotherapies for these pathogens as well as to the prediction of possible new candidate vaccine antigens.