Assessment of influenza vaccine effectiveness in a sentinel surveillance network 2010–13, United States

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Impaired Thymic Selection and Abnormal Antigen-Specific T Cell Responses in Foxn1Δ/Δ Mutant Mice

Foxn1(Δ/Δ) mutant mice have a specific defect in thymic development, characterized by a block in TEC differentiation at an intermediate progenitor stage, and blocks in thymocyte development at both the DN1 and DP cell stages, resulting in the production of abnormally functioning T cells that develop from an atypical progenitor population. In the current study, we tested the effects of these defects on thymic selection.We used Foxn1(Δ/Δ); DO11 Tg and Foxn1(Δ/Δ); OT1 Tg mice as positive selection and Foxn1(Δ/Δ); MHCII I-E mice as negative selection models. We also used an in vivo system of antigen-specific reactivity to test the function of peripheral T cells. Our data show that the capacity for positive and negative selection of both CD4 and CD8 SP thymocytes was reduced in Foxn1(Δ/Δ) mutants compared to Foxn1(+/Δ) control mice. These defects were associated with reduction of both MHC Class I and Class II expression, although the resulting peripheral T cells have a broad TCR Vβ repertoire. In this deficient thymic environment, immature CD4 and CD8 SP thymocytes emigrate from the thymus into the periphery. These T cells had an incompletely activated profile under stimulation of the TCR signal in vitro, and were either hypersensitive or hyporesponsive to antigen-specific stimulation in vivo. These cell-autonomous defects were compounded by the hypocellular peripheral environment caused by low thymic output.These data show that a primary defect in the thymic microenvironment can cause both direct defects in selection which can in turn cause indirect effects on the periphery, exacerbating functional defects in T cells

Enhanced Notch Activation Is Advantageous but Not Essential for T Cell Lymphomagenesis in Id1 Transgenic Mice

T cell lymphoblastic leukemia (T-ALL) is known to be associated with chromosomal abnormalities that lead to aberrant expression of a number of transcription factors such as TAL1, which dimerizes with basic helix-loop-helix (bHLH) E proteins and inhibits their function. Activated Notch receptors also efficiently induce T cell leukemogenesis in mouse models. Interestingly, gain-of-function mutations or cryptic transcription initiation of the Notch1 gene have been frequently found in both human and mouse T-ALL. However, the correlations between these alterations and overall Notch activities or leukemogenesis have not been thoroughly evaluated. Therefore, we made use of our collection of T cell lymphomas developed in transgenic mice expressing Id1, which like TAL1, inhibits E protein function. By comparing expression levels of Notch target genes in Id1-expressing tumors to those in tumors induced by a constitutively active form of Notch1, N1C, we were able to assess the overall activities of Notch pathways and conclude that the majority of Id1-expressing tumors had elevated Notch function to a varying degree. However, 26% of the Id1-expressing tumors had no evidence of enhanced Notch activation, but that did not delay the onset of tumorigenesis. Furthermore, we examined the genetic or epigenetic alterations thought to contribute to ligand-independent activation or protein stabilization of Notch1 and found that some of the Id1-expressing tumors acquired these changes, but they are not uniformly associated with elevated Notch activities in Id1 tumor samples. In contrast, N1C-expressing tumors do not harbor any PEST domain mutations nor exhibit intragenic transcription initiation. Taken together, it appears that Notch activation provides Id1-expressing tumor cells with selective advantages in growth and survival. However, this may not be absolutely essential for lymphomagenesis in Id1 transgenic mice and additional factors could also cooperate with Id1 to induce T cell lymphoma. Therefore, a broad approach is necessary in designing T-ALL therapy

Whole-body tissue stabilization and selective extractions via tissue-hydrogel hybrids for high-resolution intact circuit mapping and phenotyping

To facilitate fine-scale phenotyping of whole specimens, we describe here a set of tissue fixation-embedding, detergent-clearing and staining protocols that can be used to transform excised organs and whole organisms into optically transparent samples within 1–2 weeks without compromising their cellular architecture or endogenous fluorescence. PACT (passive CLARITY technique) and PARS (perfusion-assisted agent release in situ) use tissue-hydrogel hybrids to stabilize tissue biomolecules during selective lipid extraction, resulting in enhanced clearing efficiency and sample integrity. Furthermore, the macromolecule permeability of PACT- and PARS-processed tissue hybrids supports the diffusion of immunolabels throughout intact tissue, whereas RIMS (refractive index matching solution) grants high-resolution imaging at depth by further reducing light scattering in cleared and uncleared samples alike. These methods are adaptable to difficult-to-image tissues, such as bone (PACT-deCAL), and to magnified single-cell visualization (ePACT). Together, these protocols and solutions enable phenotyping of subcellular components and tracing cellular connectivity in intact biological networks

Assessment of virus interference in a test-negative study of influenza vaccine effectiveness

Oral Abstract Session - Public Heath: no. O-79BACKGROUND: The test-negative study design (TND) is an observational study design increasingly used to estimate influenza vaccine effectiveness (VE). In this variant of the case control study, one important assumption is that receipt of influenza vaccination does not affect the risk of being infected with a virus other than influenza virus. We used data from the Influenza Incidence Surveillance Project in the United States to evaluate the association between receipt of influenza vaccination and the risk of infection with non-influenza viruses. METHOD: Patients of age ≥ 6 months presenting for ambulatory care with acute respiratory infections were tested for influenza and 5 other common respiratory viruses. We used conditional logistic regression to obtain the odds ratio of influenza vaccination in cases versus controls, adjusting for age group and sex, and estimated VE as one minus the adjusted odds ratio. We evaluated the sensitivity of VE estimates by choosing three control groups: all patients that tested negative for influenza virus (VE(ANY-)), patients that tested negative for influenza but positive for another respiratory virus (VE(ORV+)) and patients that tested negative for influenza and other respiratory viruses (VE(PAN-)). We further examined the association between influenza vaccination and detection of other respiratory viruses among patients test negative for influenza viruses. RESULTS: During the 2010-11, 2011-12 and 2012-13 influenza seasons, influenza was detected in 3,743 of 10,650 patients (35.1%). The overall VE was found to be modest across three years: VE(ANY-) was 47% (95% CI: 42%, 52%), VE(ORV+) was 51% (44%, 57%), and VE(PAN-) was 44% (38%, 50%). VE estimates with each control group were consistent overall or when stratified by age groups, influenza season, early/middle/late phase within each season and influenza type/subtype. We found no statistically significant association between influenza vaccination and detection of RSV, rhinovirus, PIV 1-3, MPV and adenovirus for each age group compared with pan-negative controls. CONCLUSION: In this 3-year test-negative study in the United States, we did not find any evidence that receipt of influenza vaccination affected the risk of infection with another respiratory virus. Among patients testing negative for an influenza virus, we found no significant associations between detection of other respiratory viruses and receipt of influenza vaccination