Search

Whether class-size reductions improve student learning outcomes is an important policy question for India. This paper investigates the issue using a credible identification strategy to address the endogeneity of class size. Pupil fixed effects combined with value-added estimation show no significant relationship between class size and student achievement, which suggests that under current teaching practices, there is no learning gain from reducing class size. If these findings, based on a small sample in one city, hold true for the entire country, they have important policy implications. When generalized, our findings suggest that India experienced a value-subtraction from spending on reducing class sizes, and that the US$3.6 billion it spends annually on the salaries of the 0.4 million new teachers appointed between 2010 and 2017 is wasteful spending rather than an investment in improving learning. These findings imply that India could save US$19.4 billion per annum by increasing PTR to 40, without any reduction in pupil learning. [ABSTRACT FROM AUTHOR]

Most modern research into the immune effects of breast milk has focused on the impacts of immunoglobulin or oligosaccharide content. However, immediately prior to parturition, the cell populations of breast milk become selectively enriched for CD8+ T cells of an effector memory subtype. Despite this observation that the cellular content of breast milk contains a distinct leukocyte population when compared to peripheral blood, the physiologic role of these CD8+ effector memory cells is unknown. Research encompassing animal models and humans has demonstrated that leukocytes are capable of transferring antigen‐specific immunity even when lysed, dialyzed to enrich for fractions less than 10 kDa, and orally administered. Our previous work built upon these reports to elucidate several aspects of this dialyzable leukocyte extract (DLE) activity: only DLE from T effector memory CD8+ cells was capable of transferring antigen‐specific immunity; the DLE activity was TCRβ dependent; dendritic cells (DCs) were the cellular target of DLE; and DLE enhanced immune activity in epithelial challenge models via induction of IL‐6 from DCs. Herein, we reveal that breast milk dialysate activates similar cytokine and genetic pathways as DLE taken from peripheral blood and murine spleens through TCRβ‐ and CD8‐dependent mechanisms. These findings suggest that the CD8+ memory T cells enriched in breast milk, even after potential lysis in the infant gut, may represent a mechanism for passive transfer of cellular immunity from mother to child. [ABSTRACT FROM AUTHOR]

Multiple candidate vaccines against Staphylococcus aureus infections have failed in clinical trials. Analysis of a recent prematurely halted vaccine trial revealed increased mortality rates among vaccine recipients in whom postsurgical S. aureus infection developed, emphasizing the potential for induction of detrimental immune responses and the need to better understand the requirements for protective immunity against S. aureus. These failures of single-antigen vaccines have prompted ongoing development of multicomponent vaccines to target the multitude of S. aureus virulence factors. In the current study, we used lethally irradiated S. aureus as a model multicomponent vaccine and showed that vaccination of mice decreased survival in a bacteremia challenge model. These deleterious effects were due to a CD4 T-cell-dependent interferon γ response and could be prevented by inhibiting development of this response during vaccination. Our results identify the potential for vaccination to induce pathological immune responses, and they have implications for recent vaccine failures and the design of future staphylococcal vaccines. [ABSTRACT FROM AUTHOR]

High-mobility group box 1 protein (HMGB1), a DNA-binding nuclear and cytosolic protein, is a pro-inflammatory cytokine released by monocytes and macrophages. HMGB1 as well as its B box domain induce maturation of human dendritic cells (DCs). This report demonstrates that the B box domain induces phenotypic maturation of murine bone marrow-derived dendritic cells (BM-DCs) as evidenced by increased CD86, CD40 and MHC-II expression. The B box domain enhanced secretion of pro-inflammatory cytokines and chemokines: IL-1β, IL-2, IL-5, IL-8, IL-12 and tumor necrosis factor (TNF)-α, but not IL-6 and IL-10. Furthermore, four peptides whose sequences correspond to different regions of HMGB1 induced production of IL-1β, IL-2 and IL-12 (p70), but not IL-10 and IL-6 in mouse BM-DCs. Interestingly, these peptides differed in their capacity to induce TNF-α, IL-5, IL-18 and IL-8. B box domain as well as peptide-activated DCs acted as potent stimulators of allogeneic T cells in a mixed leukocyte reaction. DCs exposed to HMGB1 peptides induced proliferation of ovalbumin-specific syngeneic T cells. These DC-activating peptides could serve as an adjuvant in immunotherapeutic or vaccine context and the selective activity of these different peptides suggests a means to customize the functional properties of DCs. [ABSTRACT FROM PUBLISHER]

Helicobacter pylori infection is characterized by infiltration of cells of the immune system, including dendritic cells, into the gastric mucosa. During chronic inflammation with Helicobacter pylori infection, a variety of cytokines are secreted into the mucosa, including interleukin-1β (IL-1β). The role of IL-1 in H. pylori infection was investigated using bone-marrow-derived dendritic cells from wild-type and IL-1 receptor-deficient (IL-1R−/−) mice. Dendritic cells were incubated with H. pylori at a multiplicity of infection of 10 and 100, and cytokine production evaluated. Helicobacter pylori SS1, H. pylori SD4, and an isogenic cagE mutant of SD4 stimulated IL-12, IL-6, IL-1β, IL-10, and tumor necrosis factor-alpha at comparable levels in dendritic cells from both wild-type and IL-1R−/− mice. IL-10 production required the higher inoculum, while IL-12 was decreased at this bacterial load. Pretreatment of dendritic cells with an antibody to IL-10 resulted in an increased production of IL-12, confirming the down-regulation of IL-12 by IL-10. cagE was required for maximum stimulation of IL-12 by H. pylori. We speculate that the down-regulation of IL-12 by IL-10 at the higher multiplicity of infection represents the modulation of the host inflammatory response in vivo by H. pylori when the bacterial load is high, allowing for persistent colonization of the gastric mucosa. [ABSTRACT FROM AUTHOR]

Abstract: Immunostimulatory DNA sequences and their synthetic oligonucleotide analogs (CpG-ODN) activate innate immunity and can stimulate antibacterial effects against numerous intracellular pathogens. While it has been shown previously that CpG-ODN inhibit growth of Mycobacterium avium in murine and human macrophages, we now report that Mycobacterium tuberculosis growth can be inhibited by CpG-ODN treatment of human monocyte-derived macrophages (hMDM). This inhibitory effect was reversed by IFN-γ, which has been shown repeatedly to enhance the growth of virulent M. tuberculosis in cultured hMDM. The antibacterial effect of CpG-ODN in human macrophages was specific for M. tuberculosis when compared to other intracellular pathogens including Listeria monocytogenes and Salmonella enterica serovar Dublin. These data indicate that CpG-ODN can improve the ability of hMDM to contain growth of virulent M. tuberculosis. [Copyright &y& Elsevier]

Author response. [ABSTRACT FROM AUTHOR]

Spores of Bacillus subtilis are encased in a protein coat composed of ∼80 different proteins. Recently, we reconstituted the basement layer of the coat, composed of two structural proteins (SpoVM and SpoIVA) around spore-sized silica beads encased in a lipid bilayer, to create synthetic spore-like particles termed 'SSHELs'. We demonstrated that SSHELs could display thousands of copies of proteins and small molecules of interest covalently linked to SpoIVA. In this study, we investigated the efficacy of SSHELs in delivering vaccines. We show that intramuscular vaccination of mice with undecorated one micron-diameter SSHELs elicited an antibody response against SpoIVA. We further demonstrate that SSHELs covalently modified with a catalytically inactivated staphylococcal alpha toxin variant (HlaH35L), without an adjuvant, resulted in improved protection against Staphylococcus aureus infection in a bacteremia model as compared to vaccination with the antigen alone. Although vaccination with either HlaH35L or HlaH35L conjugated to SSHELs similarly elicited the production of neutralizing antibodies to Hla, we found that a subset of memory T cells was differentially activated when the antigen was delivered on SSHELs. We propose that the particulate nature of SSHELs elicits a more robust immune response to the vaccine that results in superior protection against subsequent S. aureus infection. [ABSTRACT FROM AUTHOR]