CD4+ T cell proliferative responses to PPD and CFP-10 associate with recent M. tuberculosis infection.

Interferon-γ release assays cannot differentiate latent from active tuberculosis (TB), nor identify the recently infected with increased risk of active disease. The objective of this study was to identify biomarkers of recent infection following exposure to tuberculosis, to increase the positive predictive value for incipient TB. Contacts to patients with pulmonary TB were tested repeatedly with interferon-γ release assays and flow-cytometry. Proliferative CD4+ T cell responses to purified protein derivative (PPD) and 11 M. tuberculosis antigens were analysed. The individual probability of recent and remote infection was estimated using clinical data in a novel mathematical model and compared with CD4+ responses in a prediction model. The most specific prediction of recent infection was high CD4+ proliferative responses to CFP-10 and PPD and a low CD4+ response to ESAT-6. CD4+ proliferative responses to Rec85a, Rec85b and Rv1284 were also observed in recent infection, but did not reach significance in the prediction model. CONCLUSIONS: High CD4+ proliferative responses to CFP-10 and PPD and a low response to ESAT-6 may be used as biomarkers to improve positive predictive values for recent LTBI and thus, increased risk of incipient TB. Rec85a, Rec85b and Rv1284 are also of interest to study further in this context.

Live attenuated pertussis vaccine BPZE1 induces a broad antibody response in humans.

BACKGROUNDThe live attenuated BPZE1 vaccine candidate induces protection against B. pertussis and prevents nasal colonization in animal models. Here we report on the responses in humans receiving a single intranasal administration of BPZE1.METHODSWe performed multiple assays to dissect the immune responses induced in humans (n = 12) receiving BPZE1, with particular emphasis on the magnitude and characteristics of the antibody responses. Such responses were benchmarked to adolescents (n = 12) receiving the complete vaccination program of the currently used acellular pertussis vaccine (aPV). Using immunoproteomics analysis, potentially novel immunogenic B. pertussis antigens were identified.RESULTSAll BPZE1 vaccinees showed robust B. pertussis-specific antibody responses with regard to significant increase in 1 or more of the following parameters: IgG, IgA, and memory B cells to B. pertussis antigens. BPZE1-specific T cells showed a Th1 phenotype, and the IgG exclusively consisted of IgG1 and IgG3. In contrast, all aPV vaccines showed a Th2-biased response. Immunoproteomics profiling revealed that BPZE1 elicited broader and different antibody specificities to B. pertussis antigens as compared with the aPV that primarily induced antibodies to the vaccine antigens. Moreover, BPZE1 was superior at inducing opsonizing antibodies that stimulated ROS production in neutrophils and enhanced bactericidal function, which was in line with the finding that antibodies against adenylate cyclase toxin were only elicited by BPZE1.CONCLUSIONThe breadth of the antibodies, the Th1-type cellular response, and killing mechanisms elicited by BPZE1 may hold prospects of improving vaccine efficacy and protection against B. pertussis transmission.TRIAL REGISTRATIONClinicalTrials.gov NCT02453048, NCT00870350.FUNDINGILiAD Biotechnologies, Swedish Research Council (Vetenskapsrådet), Swedish Heart-Lung Foundation.

Three-Year Durability of Immune Responses Induced by HIV-DNA and HIV-Modified Vaccinia Virus Ankara and Effect of a Late HIV-Modified Vaccinia Virus Ankara Boost in Tanzanian Volunteers.

We explored the duration of immune responses and the effect of a late third HIV-modified vaccinia virus Ankara (MVA) boost in HIV-DNA primed and HIV-MVA boosted Tanzanian volunteers. Twenty volunteers who had previously received three HIV-DNA and two HIV-MVA immunizations were given a third HIV-MVA immunization 3 years after the second HIV-MVA boost. At the time of the third HIV-MVA, 90% of the vaccinees had antibodies to HIV-1 subtype C gp140 (median titer 200) and 85% to subtype B gp160 (median titer 100). The majority of vaccinees had detectable antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies, 70% against CRF01_AE virus-infected cells (median titer 239) and 84% against CRF01_AE gp120-coated cells (median titer 499). A high proportion (74%) of vaccinees had IFN-γ ELISpot responses, 63% to Gag and 42% to Env, 3 years after the second HIV-MVA boost. After the third HIV-MVA, there was an increase in Env-binding antibodies and ADCC-mediating antibodies relative to the response seen at the time of the third HIV-MVA vaccination, p < .0001 and p < .05, respectively. The frequency of IFN-γ ELISpot responses increased to 95% against Gag or Env and 90% to both Gag and Env, p = .064 and p = .002, respectively. In conclusion, the HIV-DNA prime/HIV-MVA boost regimen elicited potent antibody and cellular immune responses with remarkable durability, and a third HIV-MVA immunization significantly boosted both antibody and cellular immune responses relative to the levels detected at the time of the third HIV-MVA, but not to higher levels than after the second HIV-MVA.

HIV-DNA Given with or without Intradermal Electroporation Is Safe and Highly Immunogenic in Healthy Swedish HIV-1 DNA/MVA Vaccinees: A Phase I Randomized Trial.

BACKGROUND: We compared safety and immunogenicity of intradermal (ID) vaccination with and without electroporation (EP) in a phase I randomized placebo-controlled trial of an HIV-DNA prime HIV-MVA boost vaccine in healthy Swedish volunteers. METHODS: HIV-DNA plasmids encoding HIV-1 genes gp160 subtypes A, B and C; Rev B; Gag A and B and RTmut B were given ID at weeks 0, 6 and 12 in a dose of 0.6 mg. Twenty-five volunteers received vaccine using a needle-free device (ZetaJet) with (n=16) or without (n=9) ID EP (Dermavax). Five volunteers were placebo recipients. Boosting with recombinant MVA-CMDR expressing HIV-1 Env, Gag, Pol of CRF01_AE (HIV-MVA) or placebo was performed at weeks 24 and 40. Nine of the vaccinees received a subtype C CN54 gp140 protein boost together with HIV-MVA. RESULTS: The ID/EP delivery was very well tolerated. After three HIV-DNA immunizations, no statistically significant difference was seen in the IFN-γ ELISpot response rate to Gag between HIV-DNA ID/EP recipients (5/15, 33%) and HIV-DNA ID recipients (1/7, 14%, p=0.6158). The first HIV-MVA or HIV-MVA+gp140 vaccination increased the IFN-γ ELISpot response rate to 18/19 (95%). CD4+ and/or CD8+ T cell responses to Gag or Env were demonstrable in 94% of vaccinees. A balanced CD4+ and CD8+ T cell response was noted, with 78% and 71% responders, respectively. IFN-γ and IL-2 dominated the CD4+ T cell response to Gag and Env. The CD8+ response to Gag was broader with expression of IFN-γ, IL-2, MIP-1ß and/or CD107. No differences were seen between DNA vaccine groups. Binding antibodies were induced after the second HIV-MVA+/-gp140 in 93% of vaccinees to subtype C Env, with the highest titers among EP/gp140 recipients. CONCLUSION: Intradermal electroporation of HIV-DNA was well tolerated. Strong cell- and antibody-mediated immune responses were elicited by the HIV-DNA prime and HIV-MVA boosting regimen, with or without intradermal electroporation use. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number (ISRCTN) 60284968.

Detection of proliferative responses to ESAT-6 and CFP-10 by FASCIA assay for diagnosis of Mycobacterium tuberculosis infection.

There is a large and growing worldwide need for reliable tests to diagnose active and latent tuberculosis (TB). Improved methodology for identifying individuals with true latent TB (LTBI), particularly those with a recent infection, would pave the way for targeted prophylactic treatment. The traditionally used tuberculin skin test (TST) is unspecific and impractical. Interferon gamma release assays (IGRA) are more specific than the TST but, like that test, cannot discriminate either between recent and remote TB infection, or between these and a mere immunological memory of previous TB infection. The Flow-cytometric Assay for Specific Cell-mediated Immune-response in Activated whole blood (FASCIA) combines long-term antigen stimulation of whole blood and flow-cytometric analysis with quantification of the expanded T-lymphoblasts and can also be employed for measurement of cytokine responses.