Development of non-antibiotic-resistant, chromosomally based, constitutive and inducible expression systems for aroA-attenuated Salmonella enterica serovar typhimurium

Live-vaccine delivery systems expressing two model antigens from Mycoplasma hyopneumoniae, F2(P97) (Adh) and NrdF, were constructed using Salmonella enterica serovar Typhimurium aroA (STM-1), and immunogenicity in mice was evaluated. Recombinant plasmid-based expression (PBE) and chromosomally based expression (CBE) systems were constructed. The PBE system was formed by cloning both antigen genes into pJLA507 to create an operon downstream of temperature-inducible promoters. Constitutive CBE was achieved using a promoter-trapping technique whereby the promoterless operon was stably integrated into the chromosome of STM-1, and the expression of antigens was assessed. The chromosomal position of the operon was mapped in four clones. Inducible CBE was obtained by using the in vivo-induced sspA promoter and recombining the expression construct into aroD. Dual expression of the antigens was detected in all systems, with PBE producing much larger quantities of both antigens. The stability of antigen expression after in vivo passage was 100% for all CBE strains recovered. PBE and CBE strains were selected for comparison in a vaccination trial. The vaccine strains were delivered orally into mice, and significant systemic immunoglobulin M(IgM) and IgG responses against both antigens were detected among all CBE groups. No significant immune response was detected using PBE strains. Expression of recombinant antigens in S. enterica serovar Typhimurium aroA from chromosomally located strong promoters without the use of antibiotic resistance markers is a reliable and effective method of inducing a significant immune response

Circulating gluten-specific FOXP3 + CD39 + regulatory T cells have impaired suppressive function in patients with celiac disease

Background Celiac disease is a chronic immune-mediated inflammatory disorder of the gut triggered by dietary gluten. Although the effector T-cell response in patients with celiac disease has been well characterized, the role of regulatory T (Treg) cells in the loss of tolerance to gluten remains poorly understood. Objective We sought to define whether patients with celiac disease have a dysfunction or lack of gluten-specific forkhead box protein 3 (FOXP3)+ Treg cells. Methods Treated patients with celiac disease underwent oral wheat challenge to stimulate recirculation of gluten-specific T cells. Peripheral blood was collected before and after challenge. To comprehensively measure the gluten-specific CD4+ T-cell response, we paired traditional IFN-γ ELISpot with an assay to detect antigen-specific CD4+ T cells that does not rely on tetramers, antigen-stimulated cytokine production, or proliferation but rather on antigen-induced coexpression of CD25 and OX40 (CD134). Results Numbers of circulating gluten-specific Treg cells and effector T cells both increased significantly after oral wheat challenge, peaking at day 6. Surprisingly, we found that approximately 80% of the ex vivo circulating gluten-specific CD4+ T cells were FOXP3+CD39+ Treg cells, which reside within the pool of memory CD4+CD25+CD127lowCD45RO+ Treg cells. Although we observed normal suppressive function in peripheral polyclonal Treg cells from patients with celiac disease, after a short in vitro expansion, the gluten-specific FOXP3+CD39+ Treg cells exhibited significantly reduced suppressive function compared with polyclonal Treg cells. Conclusion This study provides the first estimation of FOXP3+CD39+ Treg cell frequency within circulating gluten-specific CD4+ T cells after oral gluten challenge of patients with celiac disease. FOXP3+CD39+ Treg cells comprised a major proportion of all circulating gluten-specific CD4+ T cells but had impaired suppressive function, indicating that Treg cell dysfunction might be a key contributor to disease pathogenesis

Education in vascular surgery: Critical issues around the globe—training and qualification in vascular surgery in Europe

In 1958, the Union Européene des Médecins Spécialistes (UEMS), or European Union (EU) of Medical Specialists the European Union, was founded by the professional organizations of medical specialists in Europe. Among the objectives of the UEMS are to promote the highest level of patient care in the EU and to promote the harmonization of high-quality training programs within the various specialities throughout the EU. Within the 38 Specialist Sections of the UEMS are the European Boards, which are the working groups of the Specialist Sections. In 2005 Vascular Surgery was recognized as a separate and independent Section, a monospecialty, within the UEMS. The efforts of the UEMS are directed at facilitating the free exchange of training and work of trainees and medical specialists between EU countries. This situation, in combination with large differences in requirements and length of training in vascular surgery within the EU, stresses the importance of harmonization in training and certification in vascular surgery within the EU. For that reason, the European Board of Vascular Surgery has organized voluntary examinations yearly since 1996. The candidates who pass qualify as “Fellow of the European Board of Vascular Surgery” (FEBVS) since 2005. The first part of the examination evaluates the eligibility of the candidate (Certificate of Completion of Specialist Training, training center, logbook). The second part is a viva voce assessment that includes (1) case analyses, (2) a review of a scientific article, (3) an overall assessment, (4) a technical skills, and (5) an endovascular skills assessment. To pass the examination, the candidates must achieve a 67% success rate in each part of the examination. During the last 10 years, approximately 75% of the candidates have successfully taken the examination. In the near future the Section and Board, in close collaboration with the vascular societies in the EU, will develop a European vascular surgical syllabus and curriculum that will further harmonize and professionalize the training and certification of vascular surgery in Europe

Education in vascular surgery: Critical issues around the globe-training and qualification in vascular surgery in Europe

In 1958, the Union Europeene des Medecins Specialistes (UEMS), or European Union (EU) of Medical Specialists the European Union, was founded by the professional organizations of medical specialists in Europe. Among the objectives of the U EMS arc to promote the highest level of patient care in the EU and to promote the harmonization of high-quality training programs within the various specialities throughout the EU. Within the 38 Specialist Sections of the UEMS are the European Boards, which are the working groups of the Specialist Sections. In 2005 Vascular Surgery was recognized as a separate and independent Section, a monospecialty, within the UEMS. The efforts of the UEMS are directed at facilitating the free exchange of training and work of trainees and medical specialists between EU countries. This situation, in combination with large differences in requirements and length of training in vascular surgery within the EU, stresses the importance of harmonization in training and certification in vascular surgery within the EU. For that reason, the European Board of Vascular Surgery has organized voluntary examinations yearly since 1996. The candidates who pass qualify as “Fellow of the European Board of Vascular Surgery” (FEBVS) since 2005. The first part of the examination evaluates the eligibility of the candidate (Certificate of Completion of Specialist Training, training center, logbook). The second part is a viva voce assessment that includes (1) case analyses, (2) a review of a scientific article, (3) an overall assessment, (4) a technical skills, and (5) an endovascular skills assessment. To pass the examination, the candidates must achieve a 67% success rate in each part of the examination. During the last 10 years, approximately 75% of the candidates have successfully taken the examination. In the near future the Section and Board, in close collaboration with the vascular societies in the EU, will develop a European vascular surgical syllabus and curriculum that will further harmonize and professionalize the training and certification of vascular surgery in Europe. (J Vasc Surg 2008;48:69S-75S.

Persistent survival of prevalent clonotypes within an immunodominant HIV gag-specific CD8+ T cell response

CD8+ T cells play a significant role in the control of HIV replication, yet the associated qualitative and quantitative factors that determine the outcome of infection remain obscure. In this study, we examined Ag-specific CD8+ TCR repertoires longitudinally in a cohort of HLA-B*2705+ long-term nonprogressors with chronic HIV-1 infection using a combination of molecular clonotype analysis and polychromatic flow cytometry. In each case, CD8+ T cell populations specific for the immunodominant p24 Gag epitope KRWIILGLNK (KK10; residues 263–272) and naturally occurring variants thereof, restricted by HLA-B*2705, were studied at multiple time points; in addition, comparative data were collected for CD8+ T cell populations specific for the CMV pp65 epitope NLVPMVATV (NV9; residues 495–503), restricted by HLA-A*0201. Dominant KK10-specific clonotypes persisted for several years and exhibited greater stability than their contemporaneous NV9-specific counterparts. Furthermore, these dominant KK10-specific clonotypes exhibited cross-reactivity with antigenic variants and expressed significantly higher levels of CD127 (IL-7Rα) and Bcl-2. Of note, we also found evidence that promiscuous TCR α-chain pairing associated with alterations in fine specificity for KK10 variants could contribute to TCR β-chain prevalence. Taken together, these data suggest that an antiapoptotic phenotype and the ability to cross-recognize variant epitopes contribute to clonotype longevity and selection within the peripheral memory T cell pool in the presence of persistent infection with a genetically unstable virus

Vorapaxar for HIV-associated inflammation and coagulopathy (ADVICE): a randomised, double-blind, placebo-controlled trial

Background Increased D-dimer concentrations are associated with poor cardiovascular and outer clinical outcomes in people with treated HIV infection. Proteinase activated receptor-1 (PAR-1) is activated by thrombin and overexpressed by immune cells from HIV-infected people. We aimed to study the efficacy of vorapaxar, a licensed inhibitor of PAR-1, in reducing HIV-associated hypercoagulation and inflammation.Methods This was a multicentre, double-blind, randomised, placebo-controlled trial done in seven hospital clinics in Australia and the USA. Eligible participants were HIV-infected, aviraemic, were receiving stable antiretroviral therapy, and had D-dimer concentrations greater than 200 ng/mL. We randomly assigned participants (1:1) using computer-generated block lists of size two to receive vorapaxar (2.5 mg orally daily) or matched placebo for 12 weeks. Participants were reviewed and had a blood sample taken at weeks 1, 4, 8, and 12 during treatment, and at a final visit at week 18. The primary endpoint was treatment group difference in changes from baseline D-dimer concentrations after 8-12 weeks of treatment, and was assessed in the modified intention-to-treat population (participants who had at least one dose of study drug or one follow-up visit). This trial is registered with ClinicalTrials.gov , number NCT02394730, and is closed to new participants.Findings Between Oct 21, 2015, and July 14, 2017, 65 eligible patients were randomly assigned to the placebo group (n=31) or vorapaxar group (n=34). One patient from the vorapaxar group did not receive any study drug, and the modified intention-to-treat population was comprised of 33 patients. D-dimer concentrations after 8-12 weeks of treatment did not differ significantly between groups (difference -0.02 log(10) ng/mL, 95% CI -0.10 to 0.05; p=0.56). Vorapaxar treatment was safe and well tolerated in this cohort. There were 161 adverse events (n=84 in the placebo group and n=77 in the vorapaxar group), and five protocol-defined serious adverse events that required hospital admission for more than 24 h (n=2 in the placebo group and n=3 in the vorapaxar group). One patient ceased taking vorapaxar because of an adverse event. There were 25 bleeding events, 23 of which were mild, one was moderate, and one was severe.Interpretation Vorapaxar had no effect on D-dimer concentrations in HIV-infected patients receiving stable antiretroviral therapy but at risk of poor outcomes. Alternative approaches are needed to reduce hypercoagulation, inflammation, and adverse long-term outcomes in patients with treated HIV infection. Copyright (C) 2018 Elsevier Ltd. All rights reserved

A randomized, placebo-controlled phase I trial of DNA prime, recombinant fowlpox virus boost prophylactic vaccine for HIV-1.

An HIV-vaccine consisting of a DNA prime, recombinant fowlpox virus (rFPV) boost was evaluated in a double-blind placebo controlled trial. One milligram of pHIS–HIV-B expressing mutated gag, pol, env, vpu, tat and rev was administered at weeks 0 and 4 boosted by 5 × 107 pfu rFPV–HIV-B expressing gag/pol at week 8. The vaccine regimen was safe, but there was no difference between vaccine (n = 18) and placebo recipients (n = 6) for Gag or Pol-specific T-cell immune responses at week 9

Escape from highly effective public CD8+ T-cell clonotypes by HIV

Mapping the precise determinants of T-cell efficacy against viruses in humans is a public health priority with crucial implications for vaccine design. To inform this effort, we performed a comprehensive analysis of the effective CD8+ T-cell clonotypes that constitute responses specific for the HIV p24 Gag-derived KK10 epitope (KRWIILGLNK; residues 263-272) restricted by HLA-B*2705, which are known to confer superior control of viral replication in HIV-infected individuals. Particular KK10-specific CD8+ T-cell clonotypes, characterized by TRBV4-3/TRBJ1-3 gene rearrangements, were found to be preferentially selected in vivo and shared between individuals. These “public” clonotypes exhibit high levels of TCR avidity and Ag sensitivity, which impart functional advantages and enable effective suppression of HIV replication. The early L268M mutation at position 6 of the KK10 epitope enables the virus to avoid recognition by these highly effective CD8+ T-cell clonotypes. However, alternative clonotypes with variant reactivity provide flexibility within the overall KK10-specific response. These findings provide refined mechanistic insights into the workings of an effective CD8+ T-cell response against HIV