Transnuclear CD8 T cells specific for the immunodominant epitope Gra6 lower acute-phase Toxoplasma gondii burden.

We generated a CD8 T-cell receptor (TCR) transnuclear (TN) mouse specific to the Ld -restricted immunodominant epitope of GRA6 from Toxoplasma gondii as a source of cells to facilitate further investigation into the CD8 T-cell-mediated response against this pathogen. The TN T cells bound Ld -Gra6 tetramer and proliferated upon unspecific and peptide-specific stimulation. The TCR beta sequence of the Gra6-specific TN CD8 T cells is identical in its V- and J-region to the TCR-β harboured by a hybridoma line generated in response to Gra6 peptide. Adoptively transferred Gra6 TN CD8 T cells proliferated upon Toxoplasma infection in vivo and exhibited an activated phenotype similar to host CD8 T cells specific to Gra6. The brain of Toxoplasma-infected mice carried Gra6 TN cells already at day 8 post-infection. Both Gra6 TN mice as well as adoptively transferred Gra6 TN cells were able to significantly reduce the parasite burden in the acute phase of Toxoplasma infection. Overall, the Gra6 TN mouse represents a functional tool to study the protective and immunodominant specific CD8 T-cell response to Toxoplasma in both the acute and the chronic phases of infection

The Contribution of Pre-Existing Depression to the Acute Cognitive Sequelae of Mild Traumatic Brain Injury

Frontotemporal abnormalities and cognitive dysfunction, especially in verbal memory and information processing speed, occur in both mild traumatic brain injury (mTBI) and depression. Study 1 investigated the effect of depression on cognitive performance in a sample at risk of sustaining mTBI.Seventy-eight male undergraduates completed the Depression Anxiety Stress Scales (DASS), Digit Symbol Substitution Test (DSS), Hopkins Verbal Learning Test (HVLT), and Speed of Comprehension Test. A oneway analysis of covariance (using the top 25% and bottom 25% of DASS Depression subscale scorers) showed that HVLT recognition was significantly worse in the high scorers. Study 2 examined the effects of injury type and pre-existing depression on cognitive performance in a prospective emergency department sample (within 24 hours of injury). Fifty-eight participants with mTBI (29 with depression, 29 without depression) and 47 control participants (18 with depression, 29 without depression) completed the DSS, HVLT, and Speed of Comprehension Test. Participants with mTBI performed worse than controls (uninjured and orthopaedic-injured participants) on all tests. Participants with depression did not perform worse than participants without depression on the tests. However, there was a significant univariate interaction for HVLT recognition, participants in the mTBI group with depression exhibited worse recognition compared to participants without depression. Since word recognition was impaired in participants who were more depressed in both samples, this suggests that it is a consistent finding. More importantly, the results of Study 2 indicate that depression may interact with mTBI to impair word recognition during the acute phase after head injury

Massively Parallel Microfluidic Cell-Pairing Platform for the Statistical Study of Immunological Cell-Cell Interactions

Variability in cell-cell interactions is ubiquitous and particularly relevant for the immune system, where the reliability of cell-cell interactions is critical for the prevention of disease. This variability is poorly understood mainly due to the limitations of current methods. We have therefore designed a highly parallel microfluidic cell-pairing device and optimized its pairing efficiency using fluids modeling. The optimized device can hydrodynamically pair hundreds of primary mouse immune-cells at an efficiency of ~50%. We measured T cell activation dynamics of ~130 primary mouse T cells paired with B cells. Our findings represent the first time that variation has been observed in T cell activation dynamics.National Institutes of Health (U.S.) (NIH (EB008550))Singapore-MIT Allianc

Do the constants of nature couple to strong gravitational fields?

Recently, white dwarf stars have found a new use in the fundamental physics community. Many prospective theories of the fundamental interactions of Nature allow traditional constants, like the fine structure constant $\alpha$, to vary in some way. A study by Berengut et al. (2013) used the Fe/Ni V line measurements made by Preval et al. (2013) from the hot DA white dwarf G191-B2B, in an attempt to detect any variation in $\alpha$. It was found that the Fe V lines indicated an increasing alpha, whereas the Ni V lines indicated a decreasing alpha. Possible explanations for this could be misidentification of the lines, inaccurate atomic data, or wavelength dependent distortion in the spectrum. We examine the first two cases by using a high S/N reference spectrum from the hot sdO BD+28$^{\circ}$4211 to calibrate the Fe/Ni V atomic data. With this new data, we re-evaluate the work of Berengut et al. (2013) to derive a new constraint on the variation of alpha in a gravitational field.Comment: 4 pages, 2 figures: To appear in the proceedings of the "19th European White Dwarf Workshop" in Montreal, Canada, 201

Transnuclear TRP1-Specific CD8 T Cells with High or Low Affinity TCRs Show Equivalent Antitumor Activity

We have generated, via somatic cell nuclear transfer, two independent lines of transnuclear (TN) mice, using as nuclear donors CD8 T cells, sorted by tetramer staining, that recognize the endogenous melanoma antigen TRP1. These two lines of nominally identical specificity differ greatly in their affinity for antigen (TRP1(high) or TRP1(low)) as inferred from tetramer dissociation and peptide responsiveness. Ex vivo-activated CD8 T cells from either TRP1(high) or TRP1(low) mice show cytolytic activity in 3D tissue culture and in vivo, and slow the progression of subcutaneous B16 melanoma. Although naïve TRP1(low) CD8 T cells do not affect tumor growth, upon activation these cells function indistinguishably from TRP1(high) cells in vivo, limiting tumor cell growth and increasing mouse survival. The anti-tumor effect of both TRP1(high) and TRP1(low) CD8 T cells is enhanced in RAG-deficient hosts. However, tumor outgrowth eventually occurs, likely due to T cell exhaustion. The TRP1 TN mice are an excellent model for examining the functional attributes of T cells conferred by TCR affinity, and they may serve as a platform for screening immunomodulatory cancer therapies

A mutant of Burkholderia pseudomallei, auxotrophic in the branched chain amino acid biosynthetic pathway, is attenuated and protective in a murine model of melioidosis.

Using a transposon mutagenesis approach, we have identified a mutant of Burkholderia pseudomallei that is auxotrophic for branched chain amino acids. The transposon was shown to have interrupted the ilvI gene encoding the large subunit of the acetolactate synthase enzyme. Compared to the wild type, this mutant was significantly attenuated in a murine model of disease. Mice inoculated intraperitoneally with the auxotrophic mutant, 35 days prior to challenge, were protected against a challenge dose of 6,000 median lethal doses of wild-type B. pseudomallei

Therapist Experiences of Congruence in School-Based Counselling

Congruence is a key counselling concept, cited as the most important of the therapist provided conditions (Rogers, 1967). Whilst literature on congruence and its use within the therapeutic relationship is rich, there is a lack of research exploring how counsellors understand and experience congruence with children in school-based counselling programmes. This study explored how counsellors perceive, experience, and offer congruence with children in school-based counselling. Using phenomenology and hermeneutics as a philosophical basis, semi-structured interviews were conducted with three person-centred counsellors and one integrative counsellor who currently work with children in a school-based counselling service. The data was analysed using interpretative phenomenological analysis (IPA). This analysis found the following themes: (1) Intrapersonal Congruence and (2) Navigating Multiple Terrains. Participants identified intrapersonal congruence of paramount importance when working with children. Moments of insightful non-disclosure of therapist process are common and serve to enhance the therapeutic relationship with children. The ‘self’ of the therapist, and the presence of certain aspects of self in the therapy room, can impact upon congruence. Therapist personal self-disclosure was essential in facilitating a strong therapeutic alliance with children; this paper argues it should be considered a central aspect of congruence with children. Finally, lack of clarity around the unique roles and responsibilities of working in a school setting as a counsellor affected the way therapists experience and offer congruence with children and young people. Implications for training and practice are also considered

XBP-1 regulates signal transduction, transcription factors and bone marrow colonization in B cells

XBP-1, a transcription factor that drives the unfolded protein response (UPR), is activated in B cells when they differentiate to plasma cells. Here, we show that in the B cells, whose capacity to secrete IgM has been eliminated, XBP-1 is induced normally on induction of differentiation, suggesting that activation of XBP-1 in B cells is a differentiation-dependent event, but not the result of a UPR caused by the abundant synthesis of secreted IgM. Without XBP-1, B cells fail to signal effectively through the B-cell receptor. The signalling defects lead to aberrant expression of the plasma cell transcription factors IRF4 and Blimp-1, and altered levels of activation-induced cytidine deaminase and sphingosine-1-phosphate receptor. Using XBP-1-deficient/Blimp-1-GFP transgenic mice, we find that XBP-1-deficient B cells form antibody-secreting plasmablasts in response to initial immunization; however, these plasmablasts respond ineffectively to CXCL12. They fail to colonize the bone marrow and do not sustain antibody production. These findings define the role of XBP-1 in normal plasma cell development and have implications for management of B-cell malignancies