Immunogenicity of targeted lentivectors

To increase the safety and possibly efficacy of HIV-1 derived lentivectors (LVs) as an anti-cancer vaccine, we recently developed the Nanobody (Nb) display technology to target LVs to antigen presenting cells (APCs). In this study, we extend these data with exclusive targeting of LVs to conventional dendritic cells (DCs), which are believed to be the main cross-presenting APCs for the induction of a TH1-conducted antitumor immune response. The immunogenicity of these DC-subtype targeted LVs was compared to that of broad tropism, general APC-targeted and non-infectious LVs. Intranodal immunization with ovalbumin encoding LVs induced proliferation of antigen specific CD4(+) T cells, irrespective of the LVs' targeting ability. However, the cytokine secretion profile of the restimulated CD4(+) T cells demonstrated that general APC targeting induced a similar TH1-profile as the broad tropism LVs while transduction of conventional DCs alone induced a similar and less potent TH1 profile as the non-infectious LVs. This observation contradicts the hypothesis that conventional DCs are the most important APCs and suggests that the activation of other APCs is also meaningful. Despite these differences, all targeted LVs were able to stimulate cytotoxic T lymphocytes, be it to a lesser extent than broad tropism LVs. Furthermore this induction was shown to be dependent on type I interferon for the targeted and non-infectious LVs, but not for broad tropism LVs. Finally we demonstrated that the APC-targeted LVs were as potent in therapy as broad tropism LVs and as such deliver on their promise as safer and efficacious LV-based vaccines

Immunogenicity of human spermatozoa

Investigation and experimental design of the study was basically aimed at developing insight into the antigenicity of spermatozoa-associated proteins. Apart from studying the natural antigenicity of washed whole spermatozoa, their immunogenicity was also demonstrated _in vitro_. The whole live spermatozoa were immobilized and agglutinated _in vitro_ by the antibodies they induced in the laboratory model - a female rabbit. A regular immunization routine induced a high titre of antisperm polyclonal antibodies. To prepare a spermatozoa specific antigen which will not produce a cross-reacting antibody against other human tissues, only the motile and live spermatozoa were selected for antigen preparation. In investigation the laboratory-bred female rabbits were used as the bioactive system of production of antisperm antibody. Agglutination of whole spermatozoa has been observed on slides. The technique though simple is highly eloquent; clumping of spermatozoa confirms the existence of antisperm antibodies in the serum under examination. The results show that nature and pattern of immobilization of active motile spermatozoa are different as observed in different graphs of immobilization. The variation in spermatozoal population in antigen distribution on individual spermatozoa is reflected in different patterns of agglutination

Influenza Vaccination of young children or Antibody Immune Response and Protection after Inactivated Influenza Vaccine in Children – A Literature Review

Influenza virus infection is a major cause of morbidity and mortality in at risk populations. Children, especially under the age of two, are at an increased risk of complications associated with influenza virus infection. Evidence suggests that a single dose of influenza vaccine does not adequately protect children against circulating influenza virus. The Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunizations Practices (ACIP) recommends two doses of influenza vaccine, spaced at least four weeks apart, before the beginning of the influenza season for children between the ages of 6 months through 8 years receiving influenza vaccine for the first time. The initial dose is thought to prime the immune system, and the second dose is thought to mount a protective antibody response. We conducted a systematic literature review to summarize current evidence from randomized controlled trials (RCTs) and observational studies that compared immunogenicity and vaccine effectiveness (VE) after one or two doses of influenza vaccine in children to evaluate the evidence basis for the CDC recommendations. The search identified 727 unique articles and 82 were screened in full text for eligibility. A total of 26 studies met inclusion criteria, 16 immunogenicity and 10 VE studies. Overall, the evidence demonstrates increased immunogenicity and VE after two doses of influenz

A dose-ranging study in older adults to compare the safety and immunogenicity profiles of MF59®-adjuvanted and non-adjuvanted seasonal influenza vaccines following intradermal and intramuscular administration

Strategies to optimize responses to seasonal influenza vaccination in older adults include the use of adjuvants, higher antigen doses, and intradermal delivery. In this study adults aged >= 65 years (n = 450) received a single dose of 1 of 2 non-adjuvanted trivalent influenza vaccine (TIV) formulations administered intradermally (ID), both containing 6 mu g of A/H1N1 and B, differing in A/H3N2 content (6 mu g or 12 mu g), or a single dose of 1 of 8 TIV formulations administered intramuscularly (IM) all containing 15 mu g of A/H1N1 and B, differing in A/H3N2 hemagglutinin (HA) content (15 mu g or 30 mu g) and/or in MF59 (R) adjuvant content (0%, 25%, 50%, or 100% of the standard dose). This paper focuses on the comparisons of low-dose non-adjuvanted ID, full-dose non-adjuvanted IM and full-dose MF59-adjuvanted IM formulations (n = 270). At day 22 post-vaccination, at least one European licensure immunogenicity criterion was met by all groups against all 3 strains; however, all three criteria were met against all 3 vaccine strains by the low-dose non-adjuvanted ID and the full-dose MF59-adjuvanted IM groups only. The full-dose MF59-adjuvanted IM group elicited significantly higher immune response vs. the low-dose non-adjuvanted ID formulations for most comparisons. The full-dose MF59 adjuvanted IM groups were associated with increased pain at the site of injection (P < 0.01) compared to the ID groups, and the low-dose non-adjuvanted ID groups were associated with increased erythema, induration, and swelling at the injection site (P < 0.0001) and unsolicited AEs compared with the IM groups. There were no differences between IM and ID groups in the frequencies of subjects experiencing solicited systemic reactions. Overall, while MF59 adjuvantation increased pain at the site of injection, and intradermal delivery increased unsolicited adverse events, erythema, induration, and swelling at the injection site, both strategies of vaccination strongly enhanced the immunogenicity of seasonal influenza vaccine in older adults compared with conventional non-adjuvanted intramuscular delivery

Comparative global immune-related gene profiling of somatic cells, human pluripotent stem cells and their derivatives: implication for human lymphocyte proliferation.

Human pluripotent stem cells (hPSCs), including embryonic stem cells (ESCs) and induced PSCs (iPSCs), represent potentially unlimited cell sources for clinical applications. Previous studies have suggested that hPSCs may benefit from immune privilege and limited immunogenicity, as reflected by the reduced expression of major histocompatibility complex class-related molecules. Here we investigated the global immune-related gene expression profiles of human ESCs, hiPSCs and somatic cells and identified candidate immune-related genes that may alter their immunogenicity. The expression levels of global immune-related genes were determined by comparing undifferentiated and differentiated stem cells and three types of human somatic cells: dermal papilla cells, ovarian granulosa cells and foreskin fibroblast cells. We identified the differentially expressed genes CD24, GATA3, PROM1, THBS2, LY96, IFIT3, CXCR4, IL1R1, FGFR3, IDO1 and KDR, which overlapped with selected immune-related gene lists. In further analyses, mammalian target of rapamycin complex (mTOR) signaling was investigated in the differentiated stem cells following treatment with rapamycin and lentiviral transduction with specific short-hairpin RNAs. We found that the inhibition of mTOR signal pathways significantly downregulated the immunogenicity of differentiated stem cells. We also tested the immune responses induced in differentiated stem cells by mixed lymphocyte reactions. We found that CD24- and GATA3-deficient differentiated stem cells including neural lineage cells had limited abilities to activate human lymphocytes. By analyzing the transcriptome signature of immune-related genes, we observed a tendency of the hPSCs to differentiate toward an immune cell phenotype. Taken together, these data identify candidate immune-related genes that might constitute valuable targets for clinical applications

Boosting BCG with recombinant modified vaccinia ankara expressing antigen 85A: Different boosting intervals and implications for efficacy trials

Objectives. To investigate the safety and immunogenicity of boosting BCG with modified vaccinia Ankara expressing antigen 85A (MVA85A), shortly after BCG vaccination, and to compare this first with the immunogenicity of BCG vaccination alone and second with a previous clinical trial where MVA85A was administered more than 10 years after BCG vaccination. Design. There are two clinical trials reported here: a Phase I observational trial with MVA85A; and a Phase IV observational trial with BCG. These clinical trials were all conducted in the UK in healthy, HIV negative, BCG naı¨ve adults. Subjects were vaccinated with BCG alone; or BCG and then subsequently boosted with MVA85A four weeks later (short interval). The outcome measures, safety and immunogenicity, were monitored for six months. The immunogenicity results from this short interval BCG prime–MVA85A boost trial were compared first with the BCG alone trial and second with a previous clinical trial where MVA85A vaccination was administered many years after vaccination with BCG. Results. MVA85A was safe and highly immunogenic when administered to subjects who had recently received BCG vaccination. When the short interval trial data presented here were compared with the previous long interval trial data, there were no significant differences in the magnitude of immune responses generated when MVA85A was administered shortly after, or many years after BCG vaccination. Conclusions. The clinical trial data presented here provides further evidence of the ability of MVA85A to boost BCG primed immune responses. This boosting potential is not influenced by the time interval between prior BCG vaccination and boosting with MVA85A. These findings have important implications for the design of efficacy trials with MVA85A. Boosting BCG induced anti-mycobacterial immunity in either infancy or adolescence are both potential applications for this vaccine, given the immunological data presented here. Trial Registration. ClinicalTrials.Oxford University was the sponsor for all the clinical trials reported here

Safety and immunogenicity of H1/IC31®, an adjuvanted TB subunit vaccine, in HIV-infected adults with CD4+ lymphocyte counts greater than 350 cells/mm3: a phase II, multi-centre, double-blind, randomized, placebo-controlled trial.

BACKGROUND: Novel tuberculosis vaccines should be safe, immunogenic, and effective in various population groups, including HIV-infected individuals. In this phase II multi-centre, double-blind, placebo-controlled trial, the safety and immunogenicity of the novel H1/IC31 vaccine, a fusion protein of Ag85B-ESAT-6 (H1) formulated with the adjuvant IC31, was evaluated in HIV-infected adults. METHODS: HIV-infected adults with CD4+ T cell counts >350/mm3 and without evidence of active tuberculosis were enrolled and followed until day 182. H1/IC31 vaccine or placebo was randomly allocated in a 5:1 ratio. The vaccine was administered intramuscularly at day 0 and 56. Safety assessment was based on medical history, clinical examinations, and blood and urine testing. Immunogenicity was determined by a short-term whole blood intracellular cytokine staining assay. RESULTS: 47 of the 48 randomised participants completed both vaccinations. In total, 459 mild or moderate and 2 severe adverse events were reported. There were three serious adverse events in two vaccinees classified as not related to the investigational product. Local injection site reactions were more common in H1/IC31 versus placebo recipients (65.0% vs. 12.5%, p = 0.015). Solicited systemic and unsolicited adverse events were similar by study arm. The baseline CD4+ T cell count and HIV viral load were similar by study arm and remained constant over time. The H1/IC31 vaccine induced a persistent Th1-immune response with predominately TNF-α and IL-2 co-expressing CD4+ T cells, as well as polyfunctional IFN-γ, TNF-α and IL-2 expressing CD4+ T cells. CONCLUSION: H1/IC31 was well tolerated and safe in HIV-infected adults with a CD4+ Lymphocyte count greater than 350 cells/mm3. The vaccine did not have an effect on CD4+ T cell count or HIV-1 viral load. H1/IC31 induced a specific and durable Th1 immune response. TRIAL REGISTRATION: Pan African Clinical Trials Registry (PACTR) PACTR201105000289276

Immunogenicity and tolerability of an MF59-adjuvanted, egg-derived, A/H1N1 pandemic influenza vaccine in children 6-35 months of age

Background: Vaccines against pandemic A/H1N1 influenza should provide protective immunity in children, because they are at greater risk of disease than adults. This study was conducted to identify the optimal dose of an MF59 (R)-adjuvanted, egg-derived, A/H1N1 influenza vaccine for young children. Methods: Children 6-11 months (N = 144) and 12-35 months (N = 186) of age received vaccine formulations containing either 3.75 mu g antigen with half the standard dose of MF59 or 7.5 mu g antigen with a standard dose of MF59, or a nonadjuvanted formulation containing 15 mu g antigen (children 12-35 months only). Participants were given 2 primary vaccine doses 3 weeks apart, followed by 1 booster dose of MF59-adjuvanted seasonal influenza vaccine 1 year later. Immunogenicity was assessed by hemagglutination inhibition and microneutralization assays. Results: All vaccine formulations were highly immunogenic and met all 3 European licensure criteria after 2 doses. MF59-adjuvanted vaccines met all licensure criteria after 1 dose in both age cohorts, while nonadjuvanted vaccine did not meet all criteria after 1 dose in children 12-35 months. A single booster dose was highly immunogenic, and stable antibody persistence was observed in response to all vaccines. All vaccines were well tolerated. Conclusions: In this study, a single dose of 3.75 mu g antigen with half the standard dose of MF59 was shown to be optimal, providing adequate levels of immediate and long-term antibodies in pediatric subjects 6-35 months of age. These data demonstrated that MF59 adjuvant allowed for reduced antigen content and promoted significant long-term antibody persistence in children, with a satisfactory safety profile

Tumor necrosis factor inhibitors in psoriatic arthritis.

INTRODUCTION: Psoriatic arthritis (PsA) is a chronic inflammatory disease that can result in significant disability. With the emergence of tumor necrosis factor inhibitors (TNFi), therapeutic outcomes in PsA have improved substantially. The clinical efficacy and the inhibition of radiographic progression demonstrated by TNFi have transformed the management of PsA. However, there is still an unmet need for a subset of patients who do not respond adequately to TNFi. Areas covered: This review provides an overview of the pharmacokinetics of TNFi, the efficacy of TNFi in PsA, and the role of immunogenicity of TNFi in the treatment of PsA. In addition, we address the use of TNFi in the setting of other medications utilized in the treatment of PsA and the potential future role of biosimilars. Expert commentary: Monoclonal antibodies exhibit complex and widely variable pharmacokinetics. The study of factors that can affect the pharmacokinetics, such as immunogenicity, is valuable to further define and understand the use of TNFi in PsA, especially in the subset of patients who do not respond adequately to these agents or lose effectiveness over time