Browsing by Author "Kagina, Benjamin M. N."

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    Safety and Immunogenicity of Adenovirus 35 Tuberculosis Vaccine Candidate in Adults with Active or Previous Tuberculosis A Randomized Trial
    (American Journal of Respiratory and Critical Care Medicine, 2017) van Zyl-Smit, Richard N.; Esmail, Aliasgar; Bateman, Mary E.; Pau, Maria Grazia; Benko, Jacqueline; Kagina, Benjamin M. N.
    Administration of tuberculosis (TB) vaccines in participants with previous or current pulmonary TB may have the potential for causing harmful postvaccination immunologic (Koch-type) reactions. To assess the safety and immunogenicity of three dose levels of the AERAS-402 live, replication-deficient adenovirus 35–vectored TB candidate vaccine, containing three mycobacterial antigens, in individuals with current or previous pulmonary TB. We performed a phase II randomized, placebo-controlled, double-blinded dose-escalation study in an HIV-negative adult South African cohort (n = 72) with active pulmonary TB (on treatment for 1–4 mo) or pulmonary TB treated at least 12 months before study entry and considered cured. Safety endpoints included clinical assessment, flow volume curves, diffusing capacity of the lung for carbon monoxide, pulse oximetry, chest radiograph, and high-resolution thoracic computerized tomography scans. Cytokine expression by CD4 and CD8 T cells, after stimulation with Ag85A, Ag85B, and TB10.4 peptide pools, was examined by intracellular cytokine staining.
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    Specific T Cell Frequency and Cytokine Expression Profile Do Not Correlate with Protection against Tuberculosis after Bacillus Calmette-Gue´rin Vaccination of Newborns
    (American journal of respiratory and critical care medicine, 2010) Kagina, Benjamin M. N.; Scriba, Thomas J.; Sidibana, Mzwandile; Gelderbloem, Sebastian
    Immunogenicity of new tuberculosis (TB) vaccines is commonly assessed by measuring the frequency and cytokine expression profile of T cells. We tested whether this outcome correlates with protection against childhood TB disease after newborn vaccination with bacillus Calmette-Guérin (BCG). Whole blood from 10-week-old infants, routinely vaccinated with BCG at birth, was incubated with BCG for 12 hours, followed by cryopreservation for intracellular cytokine analysis. Infants were followed for 2 years to identify those who developed culture-positive TB—these infants were regarded as not protected against TB. Infants who did not develop TB disease despite exposure to TB in the household, and another group of randomly selected infants who were never evaluated for TB, were also identified—these groups were regarded as protected against TB. Cells from these groups were thawed, and CD4, CD8, and γδ T cell–specific expression of IFN-γ, TNF-α, IL-2, and IL-17 measured by flow cytometry. A total of 5,662 infants were enrolled; 29 unprotected and two groups of 55 protected infants were identified. There was no difference in frequencies of BCG-specific CD4, CD8, and γδ T cells between the three groups of infants. Although BCG induced complex patterns of intracellular cytokine expression, there were no differences between protected and unprotected infants. The frequency and cytokine profile of mycobacteria-specific T cells did not correlate with protection against TB. Critical components of immunity against Mycobacterium tuberculosis, such as CD4 T cell IFN-γ production, may not necessarily translate into immune correlates of protection against TB disease.