Tuberculin skin testing is simple and relatively inexpensive, but the specificity of PPD is affected by BCG vaccination.
Determine optimal dose and specificity of recombinant ESAT-6 and CFP-10 (C-Tb) ...produced in Lactococcus lactis for diagnosis of M. tuberculosis infection.
In a dose finding phase I trial 0.01 or 0.1 µg preserved and unpreserved C-Tb was injected by Mantoux technique in 38 patients with active tuberculosis and induration responses measured. In a phase II specificity trial in 151 uninfected, BCG vaccinated participants 0.1 µg C-Tb was compared to 2 TU PPD.
0.1 µg C-Tb gave a median induration of 15 mm after 2 days. Phenol preservation did not affect the response. The specificity of C-Tb was 99.3% (95% CI 96-100%) regarding indurations ≥5 mm as a positive outcome. This was higher than the specificity of PPD (63% using a cut-off of 5 mm or 92% using a cut-off of 15 mm to adjust for non-specific BCG responses). Local adverse reactions following C-Tb injection included transient itching and discomfort as expected components of the immune response.
C-Tb offers a simple and convenient skin test to diagnose M. tuberculosis infection using a single, universal cut-off unaffected by BCG vaccination.
ClinicalTrials.gov NCT01033929 and NCT01241188.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Highlights • H4:IC31 vaccination was well tolerated with an acceptable safety profile. • H4:IC31 vaccination elicited persistent antigen-specific CD4+ T cell responses. • H4:IC31 triggered T cell ...expansion, IFNγ production and multifunctional Th1 cells. • Optimal antigen-adjuvant doses were 5, 15, or 50 μg of H4 plus 500 nmol of IC31.
Targeted screening and treatment of Mycobacterium tuberculosis infection substantially reduces the risk of developing active tuberculosis. C-Tb (Statens Serum Institute, Copenhagen, Denmark) is a ...novel specific skin test based on ESAT-6 and CFP10 antigens. We investigated the safety and diagnostic potential of C-Tb compared with established tests in the contact-tracing setting.
Negative controls, close contacts, occasional contacts, and patients with active pulmonary tuberculosis were enrolled at 13 centres in Spain. We compared C-Tb with the QuantiFERON-TB Gold In-Tube (QFT Qiagen, Hilden, Germany) interferon γ release assay (IGRA) and the purified protein derivative (PPD) RT 23 tuberculin skin test (TST Statens Serum Institute). All participants older than 5 years were tested with QFT. Some participants in the negative control group received C-Tb without the TST to test for potential interactions between C-Tb and PPD RT 23. The rest were randomly assigned in blocks of ten and tested with both C-Tb and TST, with five in each block receiving injection of C-Tb in the right arm and the TST in the left arm and five vice versa. The primary and safety analyses were done in all participants randomly assigned to a group who received any test. This trial is registered with ClinicalTrials.gov, number NCT01631266, and with EudraCT, number 2011-005617-36.
From July 24, 2012, to Oct 2, 2014, 979 participants were enrolled, of whom 263 were negative controls, 299 were occasional contacts, 316 were close contacts, and 101 were patients with tuberculosis. 970 (99%) participants completed the trial. Induration sizes were similar for C-Tb and TST, but TST positivity was affected by BCG vaccination status. We found a strong positive trend towards C-Tb test positivity with increasing risk of infection, from 3% in negative controls to 16% in occasional contacts, to 43% in close contacts. C-Tb and QFT results were concordant in 785 (94%) of 834 participants aged 5 years and older, and results did not differ significantly between exposure groups. The safety profile of C-Tb was similar to that for the TST.
C-Tb delivered IGRA-like results in a field-friendly format. Being unaffected by BCG vaccination status, the C-Tb skin test might provide more accurate treatment guidance in settings where the TST is commonly used.
Statens Serum Institut.
Abstract Background New, more effective vaccines to prevent tuberculosis (TB) disease are needed urgently. H4:IC31 is an investigational vaccine that contains a fusion protein of the immunodominant ...antigens TB10.4 and Ag85B, formulated in IC31® adjuvant. We assessed the safety and immunogenicity of H4:IC31 in South African adults from a TB endemic setting. Methods In this double blind, placebo controlled, phase I trial, Mycobacterium tuberculosis -uninfected, HIV-uninfected, healthy adults with a history of childhood BCG vaccination were randomly allocated to two intramuscular vaccinations with 5, 15, 50 or 150 μg H4 formulated in 500 nmol IC31® , two months apart. Vaccinees were followed for six months to assess safety; immunogenicity was measured by ELISpot and intracellular cytokine staining assays. Results Thirty-two participants received H4:IC31 and 8 received placebo. Injection site adverse events were common but mild; mild fatigue was the most common systemic adverse event. Frequencies of adverse events did not differ between dosage groups. Detectable antigen-specific CD4 T cell responses were induced by all doses of H4:IC31, but doses below 50 μg induced the highest frequencies of CD4 T cells, comprised predominantly of IFN-γ+ TNF-α+ IL-2+ or TNF-α+ IL-2+ cells. These memory responses persisted up to the end of follow up, on study day 182. Conclusions H4:IC31 demonstrated an acceptable safety profile and was immunogenic in South African adults. In this trial, the 15 μg dose appeared to induce the most optimal immune response.
New TB vaccines are urgently needed because of the apparent lack of effect of the BCG vaccine on rates of adult contagious pulmonary tuberculosis and the risk of disseminated BCG disease in ...immunocompromised individuals. Since BCG appears to protect children, the primary target for vaccine development is a booster vaccine for adults but such vaccines ideally need to be able to efficiently prime mycobacterially naïve individuals as well as boost individuals previously vaccinated with BCG and those latently infected with TB. Protective immunity against Mycobacterium tuberculosis depends mainly on the generation of a Th1-type cellular immune response characterized by interferon-gamma (IFN-γ) production. In the present study, we monitored safety and IFN-γ responses in healthy BCG-vaccinated and prior or latently TB-infected individuals receiving a novel vaccine composed of the fusion protein Ag85B–ESAT-6 combined with the adjuvant IC31®, administered at 0 and 2 months. Vaccination caused few local or systemic adverse effects besides transient soreness at the injection site, but it elicited strong antigen-specific T cell responses against Ag85B–ESAT-6 and both the Ag85B and ESAT-6 components, that could be augmented by second vaccination. The strong responses persisted through 32 weeks of follow-up, indicating the induction of a persistent memory response in the vaccine recipients.
Tuberculin is still the only available skin test reagent for the diagnosis of mycobacterial infection. The product has a remarkable sensitivity, but poor specificity. Previous studies, including two ...human phase I clinical trials, have indicated that rdESAT-6 has a potential as an improved skin test reagent. Animal studies have shown that the sensitivity may be increased by inclusion of the genetically related CFP-10 antigen in the preparation without loosing specificity.
In this study a Lactococcus fermented, recombinant skin test reagent consisting of a 1ratio1 wt/wt of rdESAT-6 and CFP-10 was manufactured according to GMP standards and tested for the first time in 42 healthy adult volunteers. The two doses of 0.01 microg or 0.1 microg were injected intradermally by the Mantoux technique with 6 or 12 weeks interval. No serious adverse events and only mild adverse reactions were reported. The reagent elicited a positive skin test reaction after the first injection in one participant, who most likely was latently infected with M. tuberculosis as indicated by an appreciable IFN gamma response just below the Quantiferon(R) cut-off level at the screening visit. None of the remaining participants in the four groups had any skin test reactions and sensitisation by the reagent could therefore be excluded.
The investigational skin test reagent rdESAT-6 and CFP-10 appeared safe and non-sensitising in this first-in-man clinical trial in human volunteers and can now be tested in larger clinical trials involving individuals with latent M. tuberculosis infection or active TB disease.
ClinicalTrials.gov NCT00793702.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
H1/IC31® is a tuberculosis (TB) subunit vaccine candidate consisting of the fusion protein of Ag85B and ESAT-6 (H1) formulated with the IC31® adjuvant. Previous trials have reported on the H1/IC31® ...vaccine in M. tuberculosis (Mtb)-naïve, BCG-vaccinated and previously Mtb-infected individuals. In this trial, conducted between December 2008 and April 2010, the safety and immunogenicity of H1/IC31® was assessed in participants living in Ethiopia - a highly TB-endemic area.
Healthy male participants aged 18-25 years were recruited into four groups. Participants in group 1 (N = 12) and group 2 (N = 12) were Tuberculin Skin Test (TST) negative and QuantiFERON-TB Gold in-tube test (QFT) negative (Mtb-naïve groups), participants in group 3 (N = 3) were TST positive and QFT negative (BCG group), and participants in group 4 (N = 12) were both TST and QFT positive (Mtb-infected group). H1 vaccine alone (group 1) or H1 formulated with the adjuvant IC31® (groups 2, 3 and 4) was administered intramuscularly on day 0 and day 56. Safety and immunogenicity parameters were evaluated for up to 32 weeks after day 0.
The H1/IC31®vaccine was safe and generally well tolerated. There was little difference among the four groups, with a tendency towards a higher incidence of adverse events in Mtb-infected compared to Mtb-naïve participants. Two serious adverse events were reported in the Mtb-infected group where a relationship to the vaccine could not be excluded. In both cases the participants recovered without sequelae within 72 h. Immunogenicity assays, evaluated in the 29 participants who received both vaccinations, showed a stronger response to TB antigens in the Mtb-naïve group vaccinated with the adjuvant.
The trial confirmed the need for an adjuvant for the vaccine to be immunogenic and highlighted the importance of early phase testing of a novel TB vaccine candidate in TB-endemic areas.
ClinicalTrials.gov, ID: NCT01049282. Retrospectively registered on 14 January 2010.
There is a need for an improved vaccine for tuberculosis. ESAT-6 is a cardinal vaccine antigen with unique properties and is included in several vaccine candidates in development. ESAT-6 is also the ...core antigen in the IFN-γ release assays (IGRA) used to diagnose latent infection, rendering IGRA tests unspecific after vaccination. This challenge has prompted the development of a companion diagnostic for ESAT-6 based vaccines, an ESAT-6 free IGRA. We screened a panel of seven potential new diagnostic antigens not recognized in BCG vaccinated individuals. Three highly recognized antigens EspC, EspF and Rv2348c were identified and combined with CFP10 in an ESAT-6 free antigen cocktail. The cocktail was prepared in a field-friendly format, lyophilized with heparin in ready-to-use vacutainer tubes. The diagnostic performance of the ESAT-6 free IGRA was determined in a cross-validation study. Compared IGRA, the ESAT-6 free IGRA induced a comparable magnitude of IFN-γ release, and the diagnostic performance was on par with Quantiferon (sensitivity 84% vs 79%; specificity 99% vs 97%). The comparable performance of the ESAT-6 free IGRA to IGRA suggests potential as companion diagnostic for ESAT-6 containing vaccines and as adjunct test for latent infection.
Summary Background Regulatory T cells (Treg) are an essential arm of adaptive immunity not only in tolerance and autoimmunity but also in infectious diseases. In Tuberculosis (TB), it has been ...suggested that the frequency of Tregs is higher in the blood of TB patients when compared to healthy controls with subsequent decline after treatment. However, with the discovery that FOXP3, the hallmark marker of Tregs, is not exclusive to Tregs and the lack of specific markers for Tregs, it has been a challenge to fully understand the role of Tregs in TB. Method We isolated PBMC from smear positive TB patients (TB, N=13) before and after treatment, latent TB infected participants (LTBI, N=8), and healthy endemic controls (EC, N=9) and evaluated the frequency of different populations of Tregs and expression of FOXP3 by flowcytometry using six markers. Results The findings in this study showed that the association of Treg frequency with TB disease depends on the phenotypic markers used. While the frequency of CD4+ CD25+/hi T cells were higher in TB patients compared to LTBI individuals, there was no difference in the frequency of CD4+ CD25+ FOXP3+ CD127lo Treg among TB, LTBI, or EC. However, delineation of Tregs into active and naïve subsets revealed a significant increase in FOXP3 expression in active primed Tregs (CD4+ CD25+ FOXP3+ CD127lo CD45RO+ Ki-67+ ) of TB patients compared to LTBI and EC; and a significantly higher frequency of resting primed (CD45RO+ Ki-67- ) Treg in QuantiFERON negative EC compared to TB patients. After treatment completion, there was a significant decline in the frequency of active primed Treg, median (IQR) from 12.4% (9.5-21.9) of Tregs to 9.3% (7.0-12.2); P=0.003 Wilcoxon signed rank test. We conclude that Treg subsets maybe differentially regulated and expressed in TB disease, cure, and infection.
Tuberculosis (TB) remains a global health problem, with vaccination being a necessary strategy for disease containment and elimination. A TB vaccine should be safe and immunogenic as well as ...efficacious in all affected populations, including HIV-infected individuals. We investigated the induction and maintenance of vaccine-induced memory CD4(+) T cells following vaccination with the subunit vaccine H1/IC31. H1/IC31 was inoculated twice on study days 0 and 56 among HIV-infected adults with CD4(+) lymphocyte counts of >350 cells/mm(3). Whole venous blood stimulation was conducted with the H1 protein, and memory CD4(+) T cells were analyzed using intracellular cytokine staining and polychromatic flow cytometry. We identified high responders, intermediate responders, and nonresponders based on detection of interleukin-2 (IL-2), tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ) expressing central (TCM) and effector memory CD4(+) T cells (TEM) 182 days after the first immunization. Amplicon-based transcript quantification using next-generation sequencing was performed to identify differentially expressed genes that correlated with vaccine-induced immune responses. Genes implicated in resolution of inflammation discriminated the responders from the nonresponders 3 days after the first inoculation. The volunteers with higher expression levels of genes involved in antiviral innate immunity at baseline showed impaired H1-specific TCM and TEM maintenance 6 months after vaccination. Our study showed that in HIV-infected volunteers, expression levels of genes involved in the antiviral innate immune response affected long-term maintenance of H1/IC31 vaccine-induced cellular immunity. (The clinical trial was registered in the Pan African Clinical Trials Registry PACTR with the identifier PACTR201105000289276.).
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