an-elisa-based-binding-competition-method-to-rapidly-determine-ligand

An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions

A comprehensive understanding of signaling pathways requires detailed knowledge regarding ligand-receptor interaction. This article describes two fast and ...

University of Edinburgh

CMV-specific T-cells are crucial to control CMV-replication post-transplant. Regulatory T-cells (T-regs) are associated with a tolerant immune state and may contribute to CMV-replication. However, T-cell subsets such as T-regs and IL-17 producing T-cells (Th-17) are not well studied in this context. We explored T-regs and Th-17 frequencies during CMV-replication after transplantation.

An analysis of regulatory T-cell and Th-17 cell dynamics during cytomegalovirus replication in solid organ transplant recipients.

Data on how different immunosuppressive drugs affect cytomegalovirus (CMV)-specific T-cell responses may help guide more rational modification of immunosuppression in patients with CMV replication. We assessed the in vitro effects of individual standard and novel immunosuppressive drugs on a broad range of CMV-specific T-cell responses.

Comparison of the effect of standard and novel immunosuppressive drugs on CMV-specific T-cell cytokine profiling.

The affliction of injecting drug use (IDU) has resulted in the emergence of a subgroup of people with a unique set of medical issues. We aimed to describe the emergency department (ED) presentations of IDUs.

Cross-sectional study of the characteristics, healthcare usage, morbidity and mortality of injecting drug users attending an inner city emergency department.

Pegylated-IFN and ribavirin remains the current treatment for chronic HCV infection in patients co-infected with HIV-1, but this regimen has low efficacy rates, particularly for HCV genotype 1/4 infection, has severe side effects and is extremely costly. Therefore, accurate prediction of treatment response is urgently required. We have recently shown that the NK cell gene, KIR2DS3 and a SNP associated with the IL28B gene synergise to increase the risk of chronic infection in primary HCV mono-infected patients. Identification of SNPs associated with the IL28B gene has also proven very powerful for predicting patient response to treatment. Patients co-infected with HIV-1 are of particular concern given they respond less well to HCV treatment, have more side effects and suffer a more rapid liver disease progression. In this study, we examined both IL28B and KIR2DS3 for their ability to predict treatment response in a cohort of HIV-1/HCV co-infected patients attending two treatment centres in Europe. We found that variation in both host genetic risk factors, IL28B and KIR2DS3, was strongly associated with sustained virological response (SVR) to treatment in our co-infected cohort (n = 149). The majority of patients who achieved a rapid virological response (RVR) achieved a SVR. However, it is currently impossible to predict treatment outcome in patients who fail to achieve an RVR. In our cohort, the presence of host genetic risk factors, IL28B-T and KIR2DS3 alleles, resulted in increased odds of treatment failure in these RVR negative patients (n = 88). Our data suggests that testing for host genetic factors will improve predicting treatment responsiveness in the clinical management of co-infected patients, and provides further evidence of the importance of the innate immune system in the immune response to HCV.

Variation in both IL28B and KIR2DS3 genes influence pegylated interferon and ribavirin hepatitis C treatment outcome in HIV-1 co-infection.

Modern post-transplant care pathways commonly encompass periods of critical care support. Infectious events account for many of these interactions making critical care physicians integral members of multidisciplinary transplant teams. Despite continuing advances in clinical care and infection prophylaxis, the morbidity and mortality attributable to infection post-transplant remains considerable. Emerging entities constantly add to the breadth of potential opportunistic pathogens. Individualized risk assessments, rapid and thorough diagnostic evaluation, and prompt initiation of appropriate antimicrobial therapies are essential. The approach to managing transplant recipients with infection in critical care is discussed and common and emerging opportunistic pathogens are reviewed.

Life-threatening infection in transplant recipients.

Feedback mechanisms between interferons α and λ (IFNs) may be affected by single nucleotide polymorphisms (SNP) in interleukin 28B (IL-28B; IFN-λ3) promoter region and may influence cytomegalovirus (CMV) replication.

Immunomodulatory Function of Interleukin 28B during primary infection with cytomegalovirus.

Infectious pathogens are responsible for high utilisation of healthcare resources globally. Attributable morbidity and mortality remains exceptionally high. Vaccines offer the potential to prime a pathogen-specific immune response and subsequently reduce disease burden. Routine vaccination has fundamentally altered the natural history of many frequently observed and serious infections. Vaccination is also recommended for persons at increased risk of severe vaccine-preventable disease. Many current nonadjuvanted vaccines are poorly effective in the elderly and immunocompromised populations, resulting in nonprotective postvaccine antibody titres, which serve as surrogate markers for protection. The vaccine-induced immune response is influenced by: (i.) vaccine factors i.e., type and composition of the antigen(s), (ii.) host factors i.e., genetic differences in immune-signalling or senescence, and (iii.) external factors such as immunosuppressive drugs or diseases. Adjuvanted vaccines offer the potential to compensate for a lack of stimulation and improve pathogen-specific protection. In this review we use influenza vaccine as a model in a discussion of the different mechanisms of action of the available adjuvants. In addition, we will appraise new approaches using "vaccine-omics" to discover novel types of adjuvants.

Vaccine adjuvants--understanding molecular mechanisms to improve vaccines.

Infection prevention is a key component of care and an important determinant of clinical outcomes in a diverse population of immunocompromised hosts. Vaccination remains a fundamental preventative strategy, and clear guidelines exist for the vaccination of immunocompromised individuals and close contacts. Unfortunately, adherence to such guidelines is frequently suboptimal, with consequent missed opportunities to prevent infection. Additionally, vaccination of immunocompromised individuals is known to produce responses inferior to those observed in immunocompetent hosts. Multiple factors contribute to this finding, and developing improved vaccination strategies for those at high risk of infectious complications remains a priority of care providers. Herein, we review potential factors contributing to vaccine outcomes, focusing on host immune responses, and propose a means for applying modern, innovative systems biology technology to model critical determinants of vaccination success. With influenza vaccine in solid organ transplants used as a case in point, novel means for stratifying individuals using a host "immunophenotype" are explored, and strategies for individualizing vaccine approaches tailored to safely optimize vaccine responses in those most at risk are discussed.

Changing face of vaccination in immunocompromised hosts.

Influenza is a major cause of morbidity and mortality in immunosuppressed persons, and vaccination often confers insufficient protection. IL-28B, a member of the interferon (IFN)-λ family, has variable expression due to single nucleotide polymorphisms (SNPs). While type-I IFNs are well known to modulate adaptive immunity, the impact of IL-28B on B- and T-cell vaccine responses is unclear. Here we demonstrate that the presence of the IL-28B TG/GG genotype (rs8099917, minor-allele) was associated with increased seroconversion following influenza vaccination (OR 1.99 p = 0.038). Also, influenza A (H1N1)-stimulated T- and B-cells from minor-allele carriers showed increased IL-4 production (4-fold) and HLA-DR expression, respectively. In vitro, recombinant IL-28B increased Th1-cytokines (e.g. IFN-γ), and suppressed Th2-cytokines (e.g. IL-4, IL-5, and IL-13), H1N1-stimulated B-cell proliferation (reduced 70%), and IgG-production (reduced>70%). Since IL-28B inhibited B-cell responses, we designed antagonistic peptides to block the IL-28 receptor α-subunit (IL28RA). In vitro, these peptides significantly suppressed binding of IFN-λs to IL28RA, increased H1N1-stimulated B-cell activation and IgG-production in samples from healthy volunteers (2-fold) and from transplant patients previously unresponsive to vaccination (1.4-fold). Together, these findings identify IL-28B as a key regulator of the Th1/Th2 balance during influenza vaccination. Blockade of IL28RA offers a novel strategy to augment vaccine responses.

IL-28B is a key regulator of B- and T-cell vaccine responses against influenza.

Influenza vaccine immunogenicity is suboptimal in immunocompromised patients. However, there are limited data on the interplay of T- and B- cell responses to vaccination with simultaneous immunosuppression.

Effect of Immunosuppression on T-Helper 2 and B-Cell Responses to Influenza Vaccination.

Type-III interferons (IFN-λ, IFNL) are the most recently described family of IFNs. This family of innate cytokines are increasingly being ascribed pivotal roles in host-pathogen interactions. Herein, we will review the accumulating evidence detailing the immune biology of IFNL during viral infection, and the implications of this novel information on means to advance the development of therapies and vaccines against existing and emerging pathogens. IFNLs exert antiviral effects via induction of IFN-stimulated genes. Common single nucleotide polymorphisms (SNPs) in the IFNL3, IFNL4 and the IFNL receptor α-subunit genes have been strongly associated with IFN-α-based treatment of chronic hepatitis C virus infection. The clinical impact of these SNPs may be dependent on the status of viral infection (acute or chronic) and the potential to develop viral resistance. Another important function of IFNLs is macrophage and dendritic cell polarization, which prime helper T-cell activation and proliferation. It has been demonstrated that IFNL increase Th1- and reduce Th2-cytokines. Therefore, can such SNPs affect the IFNL signaling and thereby modulate the Th1/Th2 balance during infection? In turn, this may influence the subsequent priming of cytotoxic T cells versus antibody-secreting B cells, with implications for the breadth and durability of the host response.

The impact of the interferon-lambda family on the innate and adaptive immune response to viral infections.

The anti-hepatitis C virus (HCV) activity of a novel monoclonal antibody (mAb; AR4A) and epigallocatechin gallate (EGCG) were studied in vitro using a HCV cell culture system and in vivo using a humanized liver mouse model capable of supporting HCV replication. Alone, both exhibit reliable cross-genotype HCV inhibition in vitro, and combination therapy completely prevented HCV infection. In vitro AR4A mAb (alone and combined with EGCG) robustly protects against the establishment of HCV genotype 1a infection. EGCG alone fails to reliably protect against an HCV challenge. In conclusion, AR4A mAb represents a safe and efficacious broadly neutralizing antibody against HCV applicable to strategies to safely prevent HCV reinfection following liver transplantation, and it lends further support to the concept of HCV vaccine development. The poor bioavailability of EGCG limits HCV antiviral activity in vitro. Liver Transpl 22:324-332, 2016. © 2015 AASLD.

Article	Year
An analysis of regulatory T-cell and Th-17 cell dynamics during cytomegalovirus replication in solid organ transplant recipients. PloS one\| PubMed ID: 23071829	2012
Comparison of the effect of standard and novel immunosuppressive drugs on CMV-specific T-cell cytokine profiling. Transplantation\| PubMed ID: 23274966	2013
Cross-sectional study of the characteristics, healthcare usage, morbidity and mortality of injecting drug users attending an inner city emergency department. Emergency medicine journal : EMJ\| PubMed ID: 23625509	2014
Variation in both IL28B and KIR2DS3 genes influence pegylated interferon and ribavirin hepatitis C treatment outcome in HIV-1 co-infection. PloS one\| PubMed ID: 23826153	2013
Life-threatening infection in transplant recipients. Critical care clinics\| PubMed ID: 24094386	2013
Immunomodulatory Function of Interleukin 28B during primary infection with cytomegalovirus. The Journal of infectious diseases\| PubMed ID: 24620020	2014
Vaccine adjuvants--understanding molecular mechanisms to improve vaccines. Swiss medical weekly\| PubMed ID: 24844935	2014
Changing face of vaccination in immunocompromised hosts. Current infectious disease reports\| PubMed ID: 24992978	2014
IL-28B is a key regulator of B- and T-cell vaccine responses against influenza. PLoS pathogens\| PubMed ID: 25503988	2014
Effect of Immunosuppression on T-Helper 2 and B-Cell Responses to Influenza Vaccination. The Journal of infectious diseases\| PubMed ID: 25589334	2015
The impact of the interferon-lambda family on the innate and adaptive immune response to viral infections. Emerging microbes & infections\| PubMed ID: 26038748	2014
Prevention of hepatitis C virus infection using a broad cross-neutralizing monoclonal antibody (AR4A) and epigallocatechin gallate. Liver transplantation : official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society\| PubMed ID: 26389583	2016

Daire O'Shea

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