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1.  Longitudinal Changes in CD4+ T-Cell Memory Responses Induced by BCG Vaccination of Newborns 
The Journal of Infectious Diseases  2013;207(7):1084-1094.
Background. Improved vaccination strategies against tuberculosis are needed, such as approaches to boost immunity induced by the current vaccine, BCG. Design of these strategies has been hampered by a lack of knowledge of the kinetics of the human host response induced by neonatal BCG vaccination. Furthermore, the functional and phenotypic attributes of BCG-induced long-lived memory T-cell responses remain unclear.
Methods. We assessed the longitudinal CD4+ T-cell response following BCG vaccination of human newborns. The kinetics, function, and phenotype of these cells were measured using flow cytometric whole-blood assays.
Results. We showed that the BCG-specific CD4+ T-cell response peaked 6–10 weeks after vaccination and gradually waned over the first year of life. Highly activated T-helper 1 cells, predominantly expressing interferon γ, tumor necrosis factor α, and/or interleukin 2, were present at the peak response. Following contraction, BCG-specific CD4+ T cells expressed high levels of Bcl-2 and displayed a predominant CD45RA–CCR7+ central memory phenotype. However, cytokine and cytotoxic marker expression by these cells was more characteristic of effector memory cells.
Conclusions. Our findings suggest that boosting of BCG-primed CD4+ T cells with heterologous tuberculosis vaccines may be best after 14 weeks of age, once an established memory response has developed.
doi:10.1093/infdis/jis941
PMCID: PMC3583271  PMID: 23293360
Bacille Calmette-Guérin; Vaccination; Newborns; Memory T cells; T cell kinetics
2.  Induction and Regulation of T-Cell Immunity by the Novel Tuberculosis Vaccine M72/AS01 in South African Adults 
Rationale: Tuberculosis (TB) is a major cause of morbidity and mortality worldwide, thus there is an urgent need for novel TB vaccines.
Objectives: We investigated a novel TB vaccine candidate, M72/AS01, in a phase IIa trial of bacille Calmette-Guérin–vaccinated, HIV-uninfected, and Mycobacterium tuberculosis (Mtb)–infected and -uninfected adults in South Africa.
Methods: Two doses of M72/AS01 were administered to healthy adults, with and without latent Mtb infection. Participants were monitored for 7 months after the first dose; cytokine production profiles, cell cycling, and regulatory phenotypes of vaccine-induced T cells were measured by flow cytometry.
Measurements and Main Results: The vaccine had a clinically acceptable safety profile, and induced robust, long-lived M72-specific T-cell and antibody responses. M72-specific CD4 T cells produced multiple combinations of Th1 cytokines. Analysis of T-cell Ki67 expression showed that most vaccination-induced T cells did not express Th1 cytokines or IL-17; these cytokine-negative Ki67+ T cells included subsets of CD4 T cells with regulatory phenotypes. PD-1, a negative regulator of activated T cells, was transiently expressed on M72-specific CD4 T cells after vaccination. Specific T-cell subsets were present at significantly higher frequencies after vaccination of Mtb-infected versus -uninfected participants.
Conclusions: M72/AS01 is clinically well tolerated in Mtb-infected and -uninfected adults, induces high frequencies of multifunctional T cells, and boosts distinct T-cell responses primed by natural Mtb infection. Moreover, these results provide important novel insights into how this immunity may be appropriately regulated after novel TB vaccination of Mtb-infected and -uninfected individuals.
Clinical trial registered with www.clinicaltrials.gov (NCT 00600782).
doi:10.1164/rccm.201208-1385OC
PMCID: PMC3778736  PMID: 23306546
tuberculosis; vaccine; T cell; cytokine; proliferation
3.  A Phase IIa Trial of the New Tuberculosis Vaccine, MVA85A, in HIV- and/or Mycobacterium tuberculosis–infected Adults 
Rationale: Novel tuberculosis (TB) vaccines should be safe and effective in populations infected with Mycobacterium tuberculosis (M.tb) and/or HIV for effective TB control.
Objective: To determine the safety and immunogenicity of MVA85A, a novel TB vaccine, among M.tb- and/or HIV-infected persons in a setting where TB and HIV are endemic.
Methods: An open-label, phase IIa trial was conducted in 48 adults with M.tb and/or HIV infection. Safety and immunogenicity were analyzed up to 52 weeks after intradermal vaccination with 5 × 107 plaque-forming units of MVA85A. Specific T-cell responses were characterized by IFN-γ enzyme-linked immunospot and whole blood intracellular cytokine staining assays.
Measurements and Main Results: MVA85A was well tolerated and no vaccine-related serious adverse events were recorded. MVA85A induced robust and durable response of mostly polyfunctional CD4+ T cells, coexpressing IFN-γ, tumor necrosis factor-α, and IL-2. Magnitudes of pre- and postvaccination T-cell responses were lower in HIV-infected, compared with HIV-uninfected, vaccinees. No significant effect of antiretroviral therapy on immunogenicity of MVA85A was observed.
Conclusions: MVA85A was safe and immunogenic in persons with HIV and/or M.tb infection. These results support further evaluation of safety and efficacy of this vaccine for prevention of TB in these target populations.
doi:10.1164/rccm.201108-1548OC
PMCID: PMC3326425  PMID: 22281831
tuberculosis; HIV-1; vaccine; MVA85A; clinical trial
4.  The Novel Tuberculosis Vaccine, AERAS-402, Induces Robust and Polyfunctional CD4+ and CD8+ T Cells in Adults 
Rationale: AERAS-402 is a novel tuberculosis vaccine designed to boost immunity primed by bacillus Calmette-Guérin (BCG), the only licensed vaccine.
Objectives: We investigated the safety and immunogenicity of AERAS-402 in healthy Mycobacterium tuberculosis–uninfected BCG-vaccinated adults from a tuberculosis-endemic region of South Africa.
Methods: Escalating doses of AERAS-402 vaccine were administered intramuscularly to each of three groups of healthy South African BCG-vaccinated adults, and a fourth group received two injections of the maximal dose. Participants were monitored for 6 months, with all adverse effects documented. Vaccine-induced CD4+ and CD8+ T-cell immunity was characterized by an intracellular cytokine staining assay of whole blood and peripheral blood mononuclear cells.
Measurements and Main Results: AERAS-402 was well tolerated, and no vaccine-related serious adverse events were recorded. The vaccine induced a robust CD4+ T-cell response dominated by cells coexpressing IFN-γ, tumor necrosis factor-α, and IL-2 (“polyfunctional” cells). AERAS-402 also induced a potent CD8+ T-cell response, characterized by cells expressing IFN-γ and/or tumor necrosis factor-α, which persisted for the duration of the study.
Conclusions: Vaccination with AERAS-402 is safe and immunogenic in healthy adults. The immunity induced by the vaccine appears promising: polyfunctional T cells are thought to be important for protection against intracellular pathogens such as Mycobacterium tuberculosis, and evidence is accumulating that CD8+ T cells are also important. AERAS-402 induced a robust and durable CD8+ T-cell response, which appears extremely promising.
Clinical trial registered with www.sanctr.gov.za (NHREC no. 1381).
doi:10.1164/rccm.200910-1484OC
PMCID: PMC2894413  PMID: 20167847
tuberculosis; vaccine; immunity; CD4; CD8

Results 1-4 (4)