Interaction between C-Tb and PPD given concomitantly in a split-body randomised controlled trial.

Setting: Seven tuberculosis (TB) clinics in South Africa.

Objective: As both purified protein derivative (PPD) and a -specific skin test (C-Tb) contain region of difference 1 (RD1) antigens, we conducted a study to evaluate whether there was any interaction between the two during concomitant and separate administration in patients with newly diagnosed culture-positive TB.

Design: Adult patients with active TB ( = 456, 20% human immunodeficiency virus infected) were randomised to receive only C-Tb, only PPD, or concomitant injection of both C-Tb and PPD using the Mantoux technique.

C-Tb skin test to diagnose Mycobacterium tuberculosis infection in children and HIV-infected adults: A phase 3 trial.

Background: C-Tb, an ESAT-6/CFP-10-based skin test, has similar sensitivity for active TB compared to tuberculin skin test (TST) and QuantiFERON-TB-Gold-In-Tube (QFT). However, data are limited in children and HIV-infected persons.

Methods: Asymptomatic South African contacts <5 years (n = 87; HIV-uninfected), or symptomatic individuals of all ages presenting to clinics with suspected TB (n = 1003; 30% HIV-infected) were recruited from eight South African centres.

Safety and efficacy of the C-Tb skin test to diagnose Mycobacterium tuberculosis infection, compared with an interferon γ release assay and the tuberculin skin test: a phase 3, double-blind, randomised, controlled trial.

Background: 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.

Sensitivity of C-Tb: a novel RD-1-specific skin test for the diagnosis of tuberculosis infection.

C-Tb, a novel Mycobacterium tuberculosis and 6-kDa early secretory antigenic target/10-kDa culture filtrate protein (ESAT-6/CFP-10)-specific skin test, has high specificity in bacille Calmette-Guerin-vaccinated healthy controls. However, the sensitivity of C-Tb has hitherto not been determined. The objective was to determine the sensitivity of C-Tb in patients with active tuberculosis (TB) in comparison with the tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube (QFT-GIT).

Randomised clinical trial investigating the specificity of a novel skin test (C-Tb) for diagnosis of M. tuberculosis infection.

Background: Tuberculin skin testing is simple and relatively inexpensive, but the specificity of PPD is affected by BCG vaccination.

Objective: Determine optimal dose and specificity of recombinant ESAT-6 and CFP-10 (C-Tb) produced in Lactococcus lactis for diagnosis of M. tuberculosis infection.

First-in-man open clinical trial of a combined rdESAT-6 and rCFP-10 tuberculosis specific skin test reagent.

Background: 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.

Risk of sensitization in healthy adults following repeated administration of rdESAT-6 skin test reagent by the Mantoux injection technique.

Limited specificity of the tuberculin skin test incited the development of the intradermal Mycobacterium tuberculosis-specific rdESAT-6 skin test. Animal studies have shown, however, that there is a possible risk of sensitization when repeated injections of rdESAT-6 are given. The aim of this phase 1 open clinical trial was to assess the sensitization risk and safety of repeated administration of rdESAT-6 reagent in 31 healthy adult volunteers.

Double-blind randomized Phase I study comparing rdESAT-6 to tuberculin as skin test reagent in the diagnosis of tuberculosis infection.

Limited specificity of the tuberculin skin test incited the development of in vitro assays based on Mycobacterium tuberculosis-specific antigens such as ESAT-6 that are lacking in Bacillus Calmette Guérin (BCG). In animal studies, intradermal ESAT-6 was safe and induced specific skin test responses. The aim of the study was to assess the safety of intradermal recombinant dimer ESAT-6 (rdESAT-6) compared with tuberculin and to determine the human dose.

Safety of ESAT-6.

A recombinant dimer of the Mycobacterium tuberculosis (MTb) 6 kDa early secreted antigenic target (ESAT-6) was produced in Lactococcus lactis. Pharmacodynamic and safety studies were carried out in guinea pigs, rats, mice and dogs with intradermal (id), subcutaneous (sc) and intravenous (iv) administration of the antigen. In contrast to tuberculin purified protein derivative (PPD) the recombinant dimer (rdESAT-6) was able to discriminate MTb infection from BCG vaccination in vivo.

Specific delayed-type hypersensitivity responses to ESAT-6 identify tuberculosis-infected cattle.

Human and bovine tuberculosis have long been detected by skin testing with purified protein derivative (PPD), a complex mix of partly denatured mycobacterial antigens with suboptimal specificity. In the present study, skin tests based on ESAT-6, a recombinantly produced antigen highly specific for tuberculosis infection, were investigated. Although ESAT-6 was strongly recognized in vitro and induced high levels of gamma interferon, initial investigations demonstrated that higher doses of ESAT-6 than of PPD were needed to induce substantial delayed-type hypersensitivity reactions.

European sero-epidemiology network: standardisation of the results of diphtheria antitoxin assays.

A European Sero-Epidemiological Network (ESEN) was established with the aim to co-ordinate and harmonise serological surveillance of immunity to communicable diseases in Europe. In this study the inter-laboratory standardisation of diphtheria toxin antibody measurements is reported. A standard panel of 162 sera was tested by the participating laboratories using an in vitro assay of their choice: VERO cell toxin neutralisation assay (NT), double-antigen delayed time-resolved fluorescence immuno-assay (DA-DELFIA), double-antigen enzyme-linked immunosorbent assay (DAE), toxin binding inhibition test (ToBI) and an indirect enzyme-linked immunosorbent assay (ELISA).

Immunogenicity and safety of a tetravalent diphtheria-tetanus-acellular pertussis-inactivated poliovirus vaccine.

The objective of this study was to investigate whether a tetravalent vaccine containing diphtheria, tetanus, monocomponent acellular pertussis and inactivated poliovirus (DTaP-IPV) was immunogenic and safe compared with the vaccination regime used in Denmark at the time of the study. The study was performed as an open controlled study in which 270 Danish children were enrolled at their 5 weeks' routine examination. The children were allocated to receive either (i) DTaP-IPV (12.

Immune response to diphtheria booster vaccine in the Baltic states.

A study was done to measure baseline levels of immunity to diphtheria and antibody responses to different doses of diphtheria vaccine in study participants in the three Baltic states. Diphtheria booster vaccines containing either 3 (Estonia and Lithuania), 6 (Latvia), or 12 (Latvia) limit of flocculation units of diphtheria toxoid were administered to 2315 adults. Diphtheria antibody levels were tested before and 1-2 months after vaccination.

Intranasal vaccination: pharmaceutical evaluation of the vaccine delivery system and immunokinetic characteristics of the immune responses.

The purpose of this study was to analyze the effect of some pharmaceutical excipients when used for mucosal vaccine formulations and to characterize the achieved immune response. After conducting various pharmaceutical evaluations of the formulations, immunokinetic studies were performed in mice, guinea pigs, and rabbits. The kinetics and the characteristics (antibody isotypes, etc.

Improved ELISA for determination of anti-diphtheria and/or anti-tetanus antitoxin antibodies in sera.

Double-antigen ELISAs for detection and quantification of anti-tetanus or anti-diphtheria antibodies in serum have been developed. The assays showed good correlations with established toxin neutralizing assays and were functionally specific for IgG antibodies. The double-antigen set-up allows specific antibodies to bind to antigen-coated microtitre wells with one arm and the free arm to bind to biotin-labelled antigen.

Intranasal booster vaccination against diphtheria and tetanus in man.

The booster responses of three different formulations of intranasal (i.n.) diphtheria-tetanus (D-T) vaccines were determined in military recruits and compared with a conventional subcutaneous D-T vaccine.

Fall-off in immunity following diphtheria revaccination--an 8 year follow-up study.

Diphtheria may occur even among previously vaccinated persons and knowledge of the duration of immunity is of crucial importance when designing effective vaccination programmes. In a follow-up study of 42 representative probands revaccinated 8 years previously, a continuous fall-off in antitoxic immunity was demonstrated. 98% were still protected (antitoxin concentration > 0.

Booster vaccination against diphtheria and tetanus in man. Comparison of three different vaccine formulations--III.

Adverse reactions and antibody levels were compared following a booster vaccination of 177 Danish military recruits with a plain, an aluminium hydroxide (0.5 mg Al per human dose, HD) and a calcium phosphate (0.25 mg Ca per HD) adsorbed diphtheria-tetanus (D-T) vaccine.

Simultaneous quantitation of diphtheria and tetanus antibodies by double antigen, time-resolved fluorescence immunoassay.

A dual, double antigen, time-resolved fluorescence immunoassay (DELFIA) for the simultaneous detection and quantitation of diphtheria (D) and tetanus (T) antibodies in sera has been developed. In the double antigen format one arm of the antibody binds to antigen coated microtitre wells and the other arm binds to labelled antigen to provide a fluorescent signal. This assay was found to be functionally specific for IgG antibodies and showed a good correlation with established toxin neutralization assays.

Evaluation of local toxicity after repeated intranasal vaccination of guinea-pigs.

In intranasal vaccination it is important that the adjuvant does not have any toxic effect on the sensitive nasal mucosa. In this study a histological and clinical evaluation of the effects of two different adjuvants in a vaccine containing detoxified diphtheria (DT) and tetanus toxoid (TT) in guinea pigs was done. The guinea pigs were divided in four groups and treated daily for 14 days with different formulations.

Potency tests of diphtheria, tetanus and combined vaccines. Suggestion for a simplified potency assay.

Two diphtheria-tetanus vaccines (DT), adsorbed to either aluminium hydroxide or calcium phosphate but identical with respect to toxoid origin and amounts, were compared in full potency assays in mice according to the European Pharmacopoeia (EP) and in a reduced potency assay in guinea-pigs using a double dose immunization schedule. The efficacy of the vaccines was compared in a clinical trial with revaccination of 313 military recruits. The reduced potency assay gave a better reflection of the efficacy of the two vaccines in humans than the required assays of the EP.

Booster vaccination against diphtheria and tetanus in man. Comparison of calcium phosphate and aluminium hydroxide as adjuvants--II.

Diphtheria and tetanus antibody levels were measured before and four weeks after booster vaccination of 313 Danish military recruits participating in a clinical trial to compare aluminium hydroxide and calcium phosphate as adjuvants in diphtheria-tetanus vaccines (DT). Twenty-eight percent of the men had a diphtheria pre-vaccination content below a protective level of 0.01 IU ml-1.

Adjuvanticity of aluminium hydroxide and calcium phosphate in diphtheria-tetanus vaccines--I.

The potencies of two diphtheria-tetanus vaccines (DT) adsorbed to either aluminium hydroxide or calcium phosphate were compared in mice and guinea pigs. The vaccines were made from the same batches of purified toxoids and contained the same amounts of antigens. Immunizations were done once or twice with different doses of vaccine injected undiluted, diluted in saline or diluted in the corresponding adjuvant.

Detoxification of diphtheria and tetanus toxin with formaldehyde. Detection of protein conjugates.

In a model system of purified diphtheria and tetanus toxins it was shown that conjugates between the two proteins are formed during detoxification with formaldehyde. Detoxification mixtures were fractionated by HPLC. Two protein conjugates with different molecular weights were detected and quantified by capture ELISA assay.