Understanding the immunogenicity and antigenicity of nanomaterials: Past, present and future.

Nanoparticle immunogenicity and antigenicity have been under investigation for many years. During the past decade, significant progress has been made in understanding what makes a nanoparticle immunogenic, how immune cells respond to nanoparticles, what consequences of nanoparticle-specific antibody formation exist and how they challenge the application of nanoparticles for drug delivery. Moreover, it has been recognized that accidental contamination of therapeutic protein formulations with nanosized particulate materials may contribute to the immunogenicity of this type of biotechnology products. While the immunological properties of engineered nanomaterials and their application as vaccine carriers and adjuvants have been given substantial consideration in the current literature, little attention has been paid to nanoparticle immuno- and antigenicity. To fill in this gap, we herein provide an overview of this subject to highlight the current state of the field, review past and present research, and discuss future research directions.

Investigation of the immunogenicity of different types of aggregates of a murine monoclonal antibody in mice.

PURPOSE: The potential contribution of protein aggregates to the unwanted immunogenicity of protein pharmaceuticals is a major concern. In the present study a murine monoclonal antibody was utilized to study the immunogenicity of different types of aggregates in mice. Samples containing defined types of aggregates were prepared by processes such as stirring, agitation, exposure to ultraviolet (UV) light and exposure to elevated temperatures. METHODS: Aggregates were analyzed by size-exclusion chromatography, light obscuration, turbidimetry, infrared (IR) spectroscopy and UV spectroscopy. Samples were separated into fractions based on aggregate size by asymmetrical flow field-flow fractionation or by centrifugation. Samples containing different types and sizes of aggregates were subsequently administered to C57BL/6 J and BALB/c mice, and serum was analyzed for the presence of anti-IgG1, anti-IgG2a, anti-IgG2b and anti-IgG3 antibodies. In addition, the pharmacokinetic profile of the murine antibody was investigated. RESULTS: In this study, samples containing high numbers of different types of aggregates were administered in order to challenge the in vivo system. The magnitude of immune response depends on the nature of the aggregates. The most immunogenic aggregates were of relatively large and insoluble nature, with perturbed, non-native structures. CONCLUSION: This study shows that not all protein drug aggregates are equally immunogenic.

[Trying to unravel an unresolved issue in regenerative medicine: gene expression profiling of MSCs]. / Genexpressionsmuster mesenchymaler Stammzellen: ein ungelöster Aspekt in der regenerativen Medizin.

BACKGROUND: Mesenchymal stem cells (MSCs) are adult fibroblastoid progenitor cells. Because of their immunoregulatory properties and their so-called trophic effects, MSCs play an important role in tissue regeneration, inflammation and trauma. Tissue trauma and challenge, for example during radiotherapy or infection, result in the release of so-called "danger molecules", which may be derived from dying cells or incoming pathogens. The molecular response of MSCs to this tissue stress remains largely elusive. MATERIAL AND METHODS: In this study we examined the cell biological response of MSCs derived from human parotid glands (pgMSCs) and used bacterial endotoxin as a model of tissue stress and inflammation. PgMSCs from 3 donors were isolated, expanded and tested for classical tri-lineage plus myogenic differentiation. The cell biological response to the model "stressor" endotoxin was examined by low density gene expression arrays. RESULTS: Through immunofluorescence and immunohistochemistry we were able to proof osteogenic, adipogenic, chondrogenic, and myogenic differentiation potential characteristic for stem cells. In vitro, gene expression analysis showed a characteristic modulation of MSCs after stimulation with endotoxin Lipopolysaccharide (LPS). Specifically, receptors and ligands typically involved in immune regulation, such as interleukins, TGF-ß, tumor necrosis factors (TNF), and toll-like receptors (TLR), were regulated. CONCLUSION: Our study elucidates some key functions and molecules, which are regulated in MSCs during tissue stress and inflammation. A thorough understanding of their cell biological function will aid future rationale therapeutic application of MSCs.

[Immunogenetic features of apoptosis in workers engaged in methanol production].

Disordered cellular death process with inhibition is seen during stress states including occupational activities associated with increased concentrations of methanol in biologic media. Workers exposed to methanol demonstrate prevalence of homozygous type of tumor necrosis factor (TNF) gene and heterozygous variant of cytochrome 450 gene, reliably increased vs reference group. Genetic changes in the main group are associated with reliable decrease in occurrence of transcription protein p53 and TNF receptor, and with altered ratio of intracellular apoptosis factors (bax and bcl-2) towards slower programmed cellular death in chemical production.

Immune responses against domain I of ß(2)-glycoprotein I are driven by conformational changes: domain I of ß(2)-glycoprotein I harbors a cryptic immunogenic epitope.

OBJECTIVE: The presence of autoantibodies against a cryptic epitope in domain I of ß(2)-glycoprotein I (ß(2)GPI) is strongly associated with thrombotic events in patients with the antiphospholipid syndrome. We hypothesized that a conformational change could be a trigger for the formation of antibodies against domain I of ß(2)GPI. Therefore, we investigated whether immune responses against ß(2)GPI are related to its conformation. METHODS: Conformational changes in ß(2)GPI were studied using various techniques, either upon binding to cardiolipin or after disruption of the internal disulfide bonds. The immunogenicity of ß(2)GPI in different conformations as well as the individual domains of ß(2)GPI were studied in vivo by monitoring the generation of antibodies after intravenous administration of ß(2)GPI to mice. Furthermore, plasma samples from these mice were assessed for lupus anticoagulant activity and thrombin-antithrombin complex levels. RESULTS: We observed that the interaction of ß(2)GPI with cardiolipin induced a conformational change in ß(2)GPI: electron microscopy revealed that ß(2)GPI assembled into polymeric meshworks. We next investigated the immunogenicity of both human and murine ß(2)GPI in mice. Both human and murine ß(2)GPI combined with cardiolipin and misfolded ß(2)GPI triggered antibody formation against the native protein as well as against domain I of ß(2)GPI, while native ß(2)GPI was not immunogenic. In addition, we observed that anti-domain I antibodies developed in mice injected with domain I of ß(2)GPI, and that antibodies did not develop in mice injected with domains II-V. The induced anti-domain I antibodies prolonged the dilute Russell's viper venom plasma clotting time. The plasma of mice with anti-domain I antibodies had increased levels of circulating thrombin-antithrombin complexes. CONCLUSION: The results of our studies indicate that the exposure of cryptic epitopes due to conformational changes in ß(2)GPI can induce autoantibody formation.

Erythropoietin use and immunogenicity of hepatitis B virus vaccine in chronic kidney disease patients: a meta-analysis.

BACKGROUND: It is known that the immunogenicity of hepatitis B virus (HBV) vaccine is lower in uremic patients than healthy subjects. Numerous inherited or acquired factors have been implicated in this lowered response, and the high frequency of recombinant human erythropoietin use among patients on maintenance dialysis has been suggested to play a pivotal role. However, the impact of therapy with recombinant erythropoietin on the immune response to HBV vaccine in patients with chronic kidney disease (CKD) is not appropriately detailed. AIM: To evaluate the influence of human recombinant erythropoietin therapy on the immunological response to HBV vaccine in CKD patients by performing a systematic review of the literature with a meta-analysis of clinical studies. METHODS: We used the random-effects model of DerSimonian and Laird with heterogeneity and sensitivity analyses. The end-point of interest was the rate of patients showing seroprotective anti-hepatitis B titers at completion of a hepatitis B vaccine schedule among human erythropoietin users versus those who did not receive the drug in a CKD population. RESULTS: We identified 11 studies involving 862 unique patients with CKD. Aggregation of study results did not show a significant increase in response rates among erythropoietin user versus non-user patients (pooled odds ratio = 1.431; 95% CI 0.954; 2.146), according to a random-effects model. No heterogeneity was found, the p value was 0.1 for our test of study heterogeneity (Q = 14.147). Stratified analysis in various subgroups of interest did not significantly change these findings. CONCLUSIONS: Our meta-analysis showed no link between immunological response to HBV vaccine and therapy with human recombinant erythropoietin among individuals on long-term dialysis. We suggest the use of recombinant vaccine towards hepatitis B in patients on regular dialysis irrespective of erythropoietin treatment.

Insights from animal models on the immunogenetics of leprosy: a review.

A variety of host immunogenetic factors appear to influence both an individual's susceptibility to infection with Mycobacterium leprae and the pathologic course of the disease. Animal models can contribute to a better understanding of the role of immunogenetics in leprosy through comparative studies helping to confirm the significance of various identified traits and in deciphering the underlying mechanisms that may be involved in expression of different disease related phenotypes. Genetically engineered mice, with specific immune or biochemical pathway defects, are particularly useful for investigating granuloma formation and resistance to infection and are shedding new light on borderline areas of the leprosy spectrum which are clinically unstable and have a tendency toward immunological complications. Though armadillos are less developed in this regard, these animals are the only other natural hosts of M. leprae and they present a unique opportunity for comparative study of genetic markers and mechanisms associable with disease susceptibility or resistance, especially the neurological aspects of leprosy. In this paper, we review the recent contributions of genetically engineered mice and armadillos toward our understanding of the immunogenetics of leprosy.

[Osteoimmunology - IMMUNOBONE - Understanding the interaction between bone and immune system]. / Osteoimmunologie - IMMUNOBONE - Das Wechselspiel zwischen Knochen und Immunsystem verstehen. Schwerpunktprogramm 1468.

The special program "Osteoimmunology" under the leadership of the Universities of Erlangen, Jena, Gießen and Münster, is investigating in 27 projects clarification approaches on the causes of inflammatory rheumatic diseases, such as rheumatoid arthritis and ankylosing spondylitis with the aim of developing new forms of treatment. The molecular mechanisms involved in bone damage and the interaction between the immune system and bone and cartilage are topics of research.

Tick-borne encephalitis in children.

This review is a summary of the most important clinical findings and implications of tick-borne encephalitis (TBE) in children. It is based on a Pubmed search with the terms "tick-borne encephalitis", "children", "infection", "meningitis", "meningoencephalitis", and "outcome". TBE in children shares several features with their adult counterpart but has overall a better prognosis. Nevertheless, TBE is associated with substantial morbidity and mortality in a small group of children and seems to cause cognitive dysfunctions, which needs to be studied in further detail.

[Allergic contact dermatitis and atopy]. / Kontaktallergie und Atopie.

Retrospective studies demonstrate that the prevalence of skin sensitization does not significantly differ between atopic and non-atopic patients. In children and adolescents the risk for sensitization seems to occur independently from AD. According to the results of a recent study, AD patients are overrepresented in the group of polysensitized patients. IgE-mediated sensitization as well as an early onset of AD and duration of the disease have been identified as possible risk factors for skin sensitization to contact allergens. A defective permeability barrier with increased epidermal water loss is a hallmark of AD and contributes to sensitization against common allergens. A highly significant association between FLG mutations and the risk of early onset, severe, persistent AD and an increased risk for asthma has been shown in several studies. A more recent study revealed an association between FLG mutations and increased nickel sensitization, but not other contact allergens. However, further large prospective studies with well-characterized patients are necessary to clarify the correlation between impaired skin barrier, atopic dermatitis and allergic contact dermatitis.

Histocompatibility and immunogenetics in cord blood transplantation.

This review of the immunogenetics of cord blood transplantation attempts to highlight the connections between classical studies and conclusions of the tissue transplantation field as a scholarly endeavor, exemplified by the work of Professor Hoecker, with the motivations and some recent and key results of clinical cord blood transplantation. The authors review the evolution of understanding of transplantation biology and find that the results of the application of cord blood stem cells to Transplantation Medicine are consistent with the careful experiments of the pioneers in the field, from the results of tumor and normal tissue transplants, histocompatibility immunogenetics, to cell and molecular biology. Recent results of the National Cord Blood Program of the New York Blood Center describe the functioning in cord blood transplantation of factors, well known in transplantation immunogenetics, like the Fl anti-parent effect and the tolerance-like status of donors produced by non-inherited maternal HLA antigens. Consideration of these factors in donor selection strategies can improve the prognosis of transplantation by characterizing "permissibility" in HLA-incompatible transplantation thereby increasing the probability of survival and reducing the likelihood of leukemic relapse.

Immunogenicity of anti-TNF biologic agents in the treatment of rheumatoid arthritis.

INTRODUCTION: The use of biologic disease-modifying anti-rheumatic drugs (DMARDs), including therapeutic antibodies, antibody fragments and protein constructs that target key mediators in the pathophysiology of rheumatoid arthritis (RA), has improved the chance of achieving low disease activity and clinical remission. However, individual patients respond differently to biologic DMARD therapy, particularly the tumor necrosis factor (TNF) inhibitors. AREAS COVERED: While the variation of clinical response may be related to pharmacogenetic and other unknown factors, immunogenicity associated with some of these agents may contribute in part to a lack of efficacy and immune-mediated side effects. Timely detection of immunogenicity may avoid continued administration of ineffective treatment, and reduce unnecessary risks and costs. Access to and appropriate implementation of clinically validated drug level assays is required. EXPERT OPINION: There are currently no evidence-based recommendations to guide biologic therapy on the basis of drug level and immunogenicity testing but as more data become available and better tests are developed, a strategy of immunopharmacologic guidance to individualize treatment of RA will emerge. The potential benefits of this approach must be balanced against the costs of monitoring, and further research is required.

Epigenetics and its role in periodontal diseases: a state-of-the-art review.

The immune response to oral bacteria and the subsequent activation of inflammatory signaling is not only dependent on genetic factors. The importance of so-called epigenetic mechanisms presents additional regulatory pathways of genes involved in maintaining chronic inflammation, including gingivitis and periodontitis. The term epigenetics relates to changes in gene expression that are not encoded in the DNA sequence itself and include chemical alterations of DNA and its associated proteins. These changes lead to remodeling of the chromatin and subsequent activation or inactivation of a gene. Epigenetic mechanisms have been found to contribute to disease, including cancer and autoimmune or inflammatory diseases. In this state-of-the art review, the authors provide the latest findings on the involvement of epigenetic modifications in the development of periodontal disease and present emerging therapeutic strategies aimed at epigenetic targets (epidrugs) associated with the disruption of tissue homeostasis and the development of periodontitis.

Therapeutic potential of biosimilars in dermatology.

The introduction of biologic therapy has revolutionized the treatment of many chronic diseases, including several dermatological disorders. Biological agents promise to satisfy medical needs previously unmet by conventional medicines. Unfortunately, these agents are expensive and out of reach for the majority of patients who need them. Biosimilars are copies of the innovator biological agents and represent an important advance in the field of biological therapeutics. Although they are similar to the original biologic, differences in terms of structure, efficacy, safety and immunogenicity remain a concern. Thus, biosimilars cannot be regarded as bio-generics. Awareness of the key differences between a biosimilar and its reference biological agent is essential for optimal treatment and safety of patients. The increasing availability of biosimilars provides patients and doctors with less expensive alternatives and increases the accessibility of biologic therapy to needy patients. In this review, we discuss the concept of biosimilars, the need for appropriate regulatory pathways and their current status in dermatology.

Human immunity in vitro - solving immunogenicity and more.

It has been widely recognised that the phylogenetic distance between laboratory animals and humans limits the former's predictive value for immunogenicity testing of biopharmaceuticals and nanostructure-based drug delivery and adjuvant systems. 2D in vitro assays have been established in conventional culture plates with little success so far. Here, we detail the status of various 3D approaches to emulate innate immunity in non-lymphoid organs and adaptive immune response in human professional lymphoid immune organs in vitro. We stress the tight relationship between the necessarily changing architecture of professional lymphoid organs at rest and when activated by pathogens, and match it with the immunity identified in vitro. Recommendations for further improvements of lymphoid tissue architecture relevant to the development of a sustainable adaptive immune response in vitro are summarized. In the end, we sketch a forecast of translational innovations in the field to model systemic innate and adaptive immunity in vitro.

An explicit immunogenetic model of gastrointestinal nematode infection in sheep.

Gastrointestinal nematodes are a global cause of disease and death in humans, wildlife and livestock. Livestock infection has historically been controlled with anthelmintic drugs, but the development of resistance means that alternative controls are needed. The most promising alternatives are vaccination, nutritional supplementation and selective breeding, all of which act by enhancing the immune response. Currently, control planning is hampered by reliance on the faecal egg count (FEC), which suffers from low accuracy and a nonlinear and indirect relationship with infection intensity and host immune responses. We address this gap by using extensive parasitological, immunological and genetic data on the sheep-Teladorsagia circumcincta interaction to create an immunologically explicit model of infection dynamics in a sheep flock that links host genetic variation with variation in the two key immune responses to predict the observed parasitological measures. Using our model, we show that the immune responses are highly heritable and by comparing selective breeding based on low FECs versus high plasma IgA responses, we show that the immune markers are a much improved measure of host resistance. In summary, we have created a model of host-parasite infections that explicitly captures the development of the adaptive immune response and show that by integrating genetic, immunological and parasitological understanding we can identify new immune-based markers for diagnosis and control.

The personal touch: strategies toward personalized vaccines and predicting immune responses to them.

The impact of vaccines on public health and wellbeing has been profound. Smallpox has been eradicated, polio is nearing eradication, and multiple diseases have been eliminated from certain areas of the world. Unfortunately, we now face diseases such as hepatitis C, malaria or tuberculosis, as well as new and re-emerging pathogens for which we lack effective vaccines. Empirical approaches to vaccine development have been successful in the past, but may not be up to the current infectious disease challenges facing us. New, directed approaches to vaccine design, development, and testing need to be developed. Ideally these approaches will capitalize on cutting-edge technologies, advanced analytical and modeling strategies, and up-to-date knowledge of both pathogen and host. These approaches will pay particular attention to the causes of inter-individual variation in vaccine response in order to develop new vaccines tailored to the unique needs of individuals and communities within the population.

Comparative study of the immunogenicity in mice and monkeys of an inactivated CA16 vaccine made from a human diploid cell line.

The coxsackie A16 virus (CA16), along with enterovirus 71 (EV71), is a primary pathogen that causes hand, foot, and mouth disease (HFMD). To control HFMD, CA16, and EV71 vaccines are needed. In this study, an experimental inactivated CA16 vaccine was prepared using human diploid cells, and the vaccine's immunogenicity was analyzed in mice and rhesus monkeys. The results showed that the neutralizing antibody was developed in a dose-dependent manner, and was sustained for 70 days with an average GMT (geometric mean titer) level of 80 to 90 in immunized mouse and for 56 days with GMT of higher than 300 in monkeys. The neutralizing antibody had a cross-neutralizing activity against different viral strains (genotype A and B), and the specific IFN-γ-secreting cell response was activated by these virus strains in an ELISPOT assay. This study provides evidence for the potential use of inactivated CA16 as a candidate for use in vaccines.