Streptococcus pneumoniae is an important human pathogen responsible for a spectrum of diseases including pneumonia. Immunological and pro-inflammatory processes induced in the lung during pneumococcal infection are well documented, but little is known about the role played by immunoregulatory cells and cytokines in the control of such responses. We demonstrate considerable differences in the immunomodulatory cytokine transforming growth factor (TGF)-β between the pneumococcal pneumonia resistant BALB/c and susceptible CBA/Ca mouse strains. Immunohistochemistry and flow cytometry reveal higher levels of TGF-β protein in BALB/c lungs during pneumococcal pneumonia that correlates with a rapid rise in lung Foxp3+Helios+ T regulatory cells. These cells have protective functions during pneumococcal pneumonia, because blocking their induction with an inhibitor of TGF-β impairs BALB/c resistance to infection and aids bacterial dissemination from lungs. Conversely, adoptive transfer of T regulatory cells to CBA/Ca mice, prior to infection, prolongs survival and decreases bacterial dissemination from lungs to blood. Importantly, strong T regulatory cell responses also correlate with disease-resistance in outbred MF1 mice, confirming the importance of immunoregulatory cells in controlling protective responses to the pneumococcus. This study provides exciting new evidence for the importance of immunomodulation during pulmonary pneumococcal infection and suggests that TGF-β signalling is a potential target for immunotherapy or drug design.

A major challenge for the development of an effective vaccine against tuberculosis (TB) is that the attributes of protective CD4+ T cell responses are still elusive for human TB. Infection with human immunodeficiency virus-1 (HIV-1) is a major risk factor for tuberculosis (TB), and a better understanding of HIV-induced alterations of Mycobacterium tuberculosis (Mtb)-specific CD4+ T cells that leads to failed host resistance may provide insight into protective T cell immunity to TB. Eighty-six participants from a TB-endemic setting, either HIV-infected or -uninfected and with latent or active TB, were screened using Mtb-specific MHC class II tetramers. We examined the phenotype as well as function of ex vivo Mtb-specific tetramer+CD4+ T cells using flow cytometry. The numbers of Mtb-specific tetramer+CD4+ T cells were relatively well maintained in HIV-infected persons with active TB, despite severe immunodeficiency. However, while HIV-uninfected persons with latent TB infection exhibited ex vivo Mtb-specific CD4+ T cells predominantly of a CXCR3+CCR6+CCR4- (Th1*) phenotype; active TB or HIV infection was associated with a contraction of this subset. Nevertheless, in individuals with active TB and/or HIV infection, circulating ex vivo Mtb-specific CD4+ T cells did not display defects in exhaustion or polyfunctionality compared to healthy HIV-uninfected individuals with latent TB infection. Collectively, these data suggest that increased susceptibility to TB disease could be related to a loss of circulating Th1* CD4+ T cells rather than major changes in the number or function of circulating CD4+ T cells.

HIV-infected persons are at greater risk of developing tuberculosis (TB) even before profound CD4 loss occurs, suggesting that HIV alters CD4+T cell functions capable of containing bacterial replication. An effective immune response to Mycobacterium tuberculosis likely relies on the development of a balanced CD4 response, where distinct CD4+T helper subsets act in synergy to control the infection. To define the diversity of Mtb-specific CD4+Th subsets and determine whether HIV infection impacts such responses, the expression of lineage-defining transcription factors T-bet, Gata3, RORγt and Foxp3 was measured in Mtb-specific CD4+T cells in HIV-uninfected (n=20) and HIV-infected individuals (n=20) with latent TB infection. Our results show that upon 5 day restimulation in vitro, Mtb-specific CD4+T cells from healthy individuals have the ability to exhibit a broad spectrum of T helper subsets, defined by specific patterns of transcription factor co-expression. These transcription factor profiles were skewed in HIV-infected individuals where the proportion of T-bethighFoxp3+ Mtb-specific CD4+T cells was significantly decreased (p=0.002) compared to HIV-uninfected individuals, a change that correlated inversely with HIV viral load (p=0.0007) and plasma TNF-α (p=0.027). Our data demonstrate an important balance in T helper subset diversity defined by lineage-defining transcription factor co-expression profiles that is disrupted by HIV infection and suggest a role for HIV in impairing TB immunity by altering the equilibrium of Mtb-specific CD4+T helper subsets.

HIV genetic diversity is a major obstacle for vaccine development. To define whether potential Tcell epitope (PTE) peptide usage improves the detection of T cell responses in a highly diverse HIV-1 epidemic, we compared the magnitude, breadth and depth of group M PTE peptide responses to consensus M peptides in Gag and Nef proteins. Gag PTE responses were detected at a higher magnitude, more Nef PTE responses were detected at a cohort (but not individual) level, and depth was detected in both Gag and Nef responses.The genetic diversity of HIV represents a major challenge for the development of a universal HIV vaccine. One approach that has been developed to deal with this variability is 'mosaic' vaccine immunogens, representing sets of bioinformatically-designed sequences that attempt to maximize coverage of HIV diversity [1][2][3]. By including multiple variants for a particular epitopic region, PTE peptides are designed to increase immunological recognition of HIV. Studies in non-human primates have shown that mosaic immunogens improved the breadth and depth of cellular immune responses to globally circulating HIV-1 strains compared to consensus and natural antigens [4,5] Data from this study were presented previously at the Keystone Symposia, Banff, Alberta, Canada, March 8-14, 2014; Poster Number: 3051. Conflict of interestThere are no conflicts of interest. Testing the recognition of variant peptide sets containing 'potential T cell epitopes' (PTE peptides) based on mosaic vaccines in HIV-infected individuals represents a proxy (albeit with significant limitations) for the potential cross-reactivity of mosaic immunogens to viruses circulating in a given population [7]. To date, group M PTE peptides have not been evaluated for recognition in a highly diverse HIV-1 epidemic, such as west central Africa, which is home to virtually all HIV-1 subtypes and many circulating and unique recombinant forms (CRF and URF) [8,9]. We previously characterized the high diversity of circulating strains in HIV-1-infected blood donors from Cameroon and evaluated cellular HIV responses [8,10]. Here, we assessed the recognition of PTE peptides based on mosaic group M sequences compared to consensus (CON) group M sequences in this group. Both sets of peptides were obtained from the NIH AIDS Reagent Program (https:// www.aidsreagent.org), and CON M peptides were based on the 2001 HIV-1 group M consensus sequences from the Los Alamos National HIV sequence database, which included pure clades and recombinant forms. Europe PMC Funders GroupWe measured IFN-γ responses by ELISPOT to two 15-mer peptide panels: HIV-1 group M CON peptides spanning Gag (129 peptides) and Nef proteins (53); and group M PTE peptides for Gag (320) or Nef (127), including 0-6 variants (median 1) per epitopic region.To identify positive responses, PTE peptides were screened in pools arranged using the software "Deconvolute This" (Mario Roederer, Vaccine Research Center, NIH), in which each individual Gag and Nef peptide appeared 3-4 times; the CON set w...

The diagnosis and treatment of pain in the pediatric population is challenging because there is still much that is not understood about the development of pain systems in the human body. Many common pain syndromes manifest unique characteristics in the pediatric population that vary greatly from those in adults. In addition, pediatric treatments vary greatly from those used for adults and typically rely to a far greater degree on physical therapy or other nonpharmacologic treatments before resorting to pharmacologic or interventional therapies. Furthermore, there are many factors that must be taken into consideration when treating children, such as the child’s stage of development, pharmacokinetic and pharmacodynamic variables, caregiver concerns, psychosocial considerations, ethical considerations, and the ability of the child to describe his or her pain. This chapter highlights important topics to be considered when managing pain in pediatrics.