Biomarkers for Tuberculosis Based on Secreted, Species-Specific, Bacterial Small Molecules.

Improved biomarkers are needed for tuberculosis. To develop tests based on products secreted by tubercle bacilli that are strictly associated with viability, we evaluated 3 bacterial-derived, species-specific, small molecules as biomarkers: 2 mycobactin siderophores and tuberculosinyladenosine. Using liquid chromatography-tandem mass spectrometry, we demonstrated the presence of 1 or both mycobactins and/or tuberculosinyladenosine in serum and whole lung tissues from infected mice and sputum, cerebrospinal fluid (CSF), or lymph nodes from infected patients but not uninfected controls. Detection of the target molecules distinguished host infection status in 100% of mice with both serum and lung as the target sample. In human subjects, we evaluated detection of the bacterial small molecules (BSMs) in multiple body compartments in 3 patient cohorts corresponding to different forms of tuberculosis. We detected at least 1 of the 3 molecules in 90%, 71%, and 40% of tuberculosis patients' sputum, CSF, and lymph node samples, respectively. In paucibacillary forms of human tuberculosis, which are difficult to diagnose even with culture, detection of 1 or more BSM was rapid and compared favorably to polymerase chain reaction-based detection. Secreted BSMs, detectable in serum, warrant further investigation as a means for diagnosis and therapeutic monitoring in patients with tuberculosis.

Long-term immunogenicity and efficacy of a 9-valent conjugate pneumococcal vaccine in human immunodeficient virus infected and non-infected children in the absence of a booster dose of vaccine.

The long-term immunogenicity and vaccine efficacy (VE) of a 9-valent conjugate pneumococcal vaccine was studied in HIV infected and HIV non-infected children. VE against vaccine-serotype invasive pneumococcal disease following 6.16 years of follow-up persisted in HIV non-infected children (77.8%; 95% CI 34.4-92.5 compared to 83% after 2.3 years of follow-up), and declined from 65% to 38.8% (95% CI -7.8 to 65.2) in HIV infected children. HIV non-infected vaccinees had equal (serotypes 4, 6B, 14, 19F) or greater (serotypes 9V, 18C, 23F) proportions of serotype-specific antibody concentrations of > or =0.2microg/ml to vaccine-serotypes analyzed compared to HIV infected vaccinees at 5.3 years of age.

Pneumococcal coinfection with human metapneumovirus.

BACKGROUND: Infection with the newly discovered human metapneumovirus (hMPV) may lead to hospitalization of children with lower respiratory tract infection (LRTI), although the pathogenesis thereof remains to be elucidated. METHODS: This hypothesis-generating study involved a cohort of children randomized to receive 9-valent conjugate pneumococcal vaccine or placebo and who were tested for hMPV infection when hospitalized for LRTI. By use of a nested reverse-transcription polymerase chain reaction assay targeted at amplifying a fragment of the hMPV fusion (F) protein gene, 202 such infections were identified among 2715 episodes of LRTI in children. RESULTS: Among human immunodeficiency virus (HIV)-uninfected children who had received 3 doses of conjugate pneumococcal vaccine, the incidence of hMPV-associated LRTI was reduced by 45% (95% confidence interval [CI], 19%-62%; P = .002), and the incidence of clinical pneumonia was reduced by 55% (95% CI, 22%-74%; P = .003). Similarly, in fully vaccinated HIV-infected children, the incidence of hMPV-associated LRTI was reduced by 53% (95% CI, 3%-77%; P = .035), and that of clinical pneumonia was reduced by 65% (95% CI, 19%-85%; P = .020). CONCLUSIONS: The pathogenesis of hMPV-associated LRTI that results in hospitalization of both HIV-infected and -uninfected children involves bacterial coinfection with pneumococcus, and a significant proportion of these hospitalizations may be prevented by vaccination with pneumococcal conjugate vaccine.

A conserved N-capping motif contributes significantly to the stabilization and dynamics of the C-terminal region of class Alpha glutathione S-transferases.

Helix 9, the major structural element in the C-terminal region of class Alpha glutathione transferases, forms part of the active site of these enzymes where its dynamic properties modulate both catalytic and ligandin functions. A conserved aspartic acid N-capping motif for helix 9 was identified by sequence alignments of the C-terminal regions of class Alpha glutathione S-transferases (GSTs) and an analysis by the helix-coil algorithm AGADIR. The contribution of the N-capping motif to the stability and dynamics of the region was investigated by replacing the N-cap residue Asp-209 with a glycine in human glutathione S-transferase A1-1 (hGST A1-1) and in a peptide corresponding to its C-terminal region. Far-UV circular dichroism and AGADIR analyses indicate that, in the absence of tertiary interactions, the wild-type peptide displays a low intrinsic tendency to form a helix and that this tendency is reduced significantly by the Asp-to-Gly mutation. Disruption of the N-capping motif of helix 9 in hGST A1-1 alters the conformational dynamics of the C-terminal region and, consequently, the features of the H-site to which hydrophobic substrates (e.g. 1-chloro-2,4-dinitrobenzene (CDNB)) and nonsubstrates (e.g. 8-anilino-1-naphthalene sulfonate (ANS)) bind. Isothermal calorimetric and fluorescence data for complex formation between ANS and protein suggest that the D209G-induced perturbation in the C-terminal region prevents normal ligand-induced localization of the region at the active site, resulting in a less hydrophobic and more solvent-exposed H-site. Therefore, the catalytic efficiency of the enzyme with CDNB is diminished due to a lowered affinity for the electrophilic substrate and a lower stabilization of the transition state.