Rationale: Immunogenicity of new tuberculosis (TB) vaccines is commonly assessed by measuring the frequency and cytokine expression profile of T cells. Objectives: We tested whether this outcome correlates with protection against childhood TB disease after newborn vaccination with bacillus Calmette-Guérin (BCG). Methods: 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 gd T cell-specific expression of IFN-g, TNF-a, IL-2, and IL-17 measured by flow cytometry. Measurements and Main Results: 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 BCGspecific CD4, CD8, and gd 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. Conclusions: The frequency and cytokine profile of mycobacteriaspecific T cells did not correlate with protection against TB. Critical components of immunity against Mycobacterium tuberculosis, such as CD4 T cell IFN-g production, may not necessarily translate into immune correlates of protection against TB disease.
Chlamydia was associated with the highest genital cytokine levels, followed by gonorrhoea, HSV-2, trichomoniasis, and BV. In regions where HIV is prevalent and STIs are managed syndromically, better STI/BV screening is urgently needed, as certain infections were found to be highly inflammatory.
Vaccination with Mycobacterium bovis bacille Calmette-Guerin (BCG) has variable efficacy in preventing tuberculosis. Both BCG strain and route of administration have been implicated in determining efficacy; however, these variables are not considered in current clinical recommendations for vaccine choice. We evaluated antigen-specific immunity after percutaneous or intradermal administration of Japanese BCG or intradermal administration of Danish BCG. Ten weeks after vaccination of neonates, percutaneous Japanese BCG had induced significantly higher frequencies of BCG-specific interferon- gamma -producing CD4(+) and CD8(+) T cells in BCG-stimulated whole blood than did intradermal Danish BCG. Similarly, percutaneous vaccination with Japanese BCG resulted in significantly greater secretion of the T helper 1-type cytokines interferon- gamma, tumor necrosis factor- alpha , and interleukin-2; significantly lower secretion of the T helper 2-type cytokine interleukin-4; and greater CD4(+) and CD8(+) T cell proliferation. Thus, BCG strain and route of neonatal vaccination confer different levels of immune activation, which may affect the efficacy of the vaccine.
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