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Central tolerance prevents autoimmunity, but also limits T cell responses to potentially immunodominant tumor epitopes with limited expression in healthy tissues. In peripheral antigen presenting cells (APCs), gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of disulfide bond-containing proteins, including the self and melanoma antigen tyrosinase-related protein 1 (TRP1). The role of GILT in thymic antigen processing and generation of central tolerance has not been investigated. We found that GILT enhanced the negative selection of TRP1-specific thymocytes. GILT expression was enriched in thymic APCs capable of mediating deletion, namely medullary thymic epithelial cells (mTECs) and dendritic cells, while TRP1 expression was restricted solely to mTECs. GILT facilitated MHC class II-restricted presentation of endogenous TRP1 by pooled thymic APCs. Using bone marrow chimeras, GILT expression in thymic epithelial cells (TECs), but not hematopoietic cells, was sufficient for complete deletion of TRP1-specific thymocytes. An increased frequency of TRP1-specific regulatory T (Treg) cells was present in chimeras with increased deletion of TRP1-specific thymocytes. Only chimeras that lacked GILT in both TECs and hematopoietic cells had a high conventional T:Treg cell ratio and were protected from melanoma challenge. Thus, GILT expression in thymic APCs, and mTECs in particular, preferentially facilitates MHC class II-restricted presentation, negative selection and increased Treg cells, resulting in a diminished anti-tumor response to a tissue-restricted, melanoma-associated self antigen.

Eastern Health, a large public Victorian Healthcare network, conducted a WIES optimisation audit across the casemix-funded sites for separations in the 2009/2010 financial year. The audit was conducted using existing staff resources and resulted in a significant increase in casemix funding at a minimal cost. The audit showcased the skill set of existing staff and resulted in enormous benefits to the coding and casemix team by demonstrating the value of the combination of skills that makes clinical coders unique. The development of an internal web-based application allowed accurate and timely reporting of the audit results, providing the basis for a restructure of the coding and casemix service, along with approval for additional staffing resources and inclusion of a regular auditing program to focus on the creation of high quality data for research, health services management and financial reimbursement.

OBJECTIVES: Reports of partner violence against HIV-positive women after they have disclosed their serostatus have led some to reassess partner notification strategies and to speculate that fear of partner violence following partner notification may influence women's HIV testing decisions. We studied whether associations exist between women's declining to have an HIV test and history of partner violence, fear of partner violence, previous experience with partner notification, or beliefs about partner notification. METHODS: In this cross-sectional study, we interviewed women seen at Newark and Miami sexually transmitted disease clinics. The women were at least 18 years old, not known to be HIV positive, not tested for HIV in the previous 3 months, and offered HIV testing during the clinic visit. Women who declined testing were compared with women who accepted. RESULTS: Of 490 participants (89% of eligible women), 16% reported partner violence in the past year, and 28% declined HIV testing. Declining the test was not significantly (p >.05) associated with history or fear of partner violence, previous experience with partner notification, or beliefs about partner notification. When specifically asked, only 2 women responded that their declining the test was related to fear that their partner or partners might harm them if the women tested positive. CONCLUSIONS: Among women seen at these clinics, we did not find evidence that declining the HIV test was strongly influenced by partner violence, previous experience with partner notification, or beliefs about partner notification. However, many women reported partner violence. Therefore, providers should assess the potential for partner violence and be prepared to make appropriate referrals. Language: en

T cell-mediated immunity has the ability to produce durable anti-melanoma responses resulting in improved survival of patients with advanced melanoma. Antigen presentation in the tumor microenvironment directs anti-melanoma T cell responses. Gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of multiple melanoma antigens to CD4+ T cells. However, GILT expression in melanoma has not been defined. We evaluated GILT and MHC class II expression in human primary and metastatic melanomas and nevi using immunohistochemistry. Both GILT and MHC class II expression were increased in melanocytes of primary and metastatic melanomas compared with nevi. GILT expression was increased in antigen presenting cells of primary and metastatic melanomas compared to nevi, whereas MHC class II had equivalent high expression in antigen presenting cells of all melanocytic lesions. Keratinocytes in primary melanoma lesions had increased GILT and MHC class II expression compared with nevi. Increased GILT expression in melanocytes, antigen presenting cells and keratinocytes of melanoma demonstrates that changes in the antigen presentation pathway occur in the tumor microenvironment. GILT expression in melanoma is anticipated to result in improved presentation of melanoma antigens and more effective anti-melanoma T cell responses and may be a biomarker of immune recognition of melanoma.

Potential determinants of exposure to culturable airborne fungal and bacterial aerosols and carbon dioxide were examined as an aid to the interpretation and evaluation of indoor air quality assessments. Concentration measurments for culturable bioaerosols and CO2 were evaluated against published standards and guidelines. METHOD: All 39 schools from one British Columbia school district were enrolled in the study to ensure different building ages and construction materials, but the same maintenance protocols, were included. Schools were randomly assigned to winter, spring or fall sampling. Data collected included: number of occupants and patterns of occupancy, CO2 levels, temperature and relative humidity, total suspended particles, and air exchange rates using tracer gas (SF6) decay. Other characteristics of the classrooms included the presence or absence of forced air heat, carpets, live animals or aquaria, plants, and the siting of the school or portable classroom. Culturable indoor and outdoor aerosols of fungi and bacteria were collected. Determinants of exposure were modelled by constructing multiple linear regression equations for indoor fungi, indoor bacteria and indoor carbon dioxide. RESULTS: The multiple regression models were able to explain a considerable proportion of the variance for the outcomes of interest (total R2 = 0.59 for mesophilic fungi, 0.61 for bacteria, and 0.68 for CO2). Increased outdoor temperature and outdoor fungal counts were associated with higher concentrations for indoor fungi. Variables describing ventilation and conditions of occupancy were significant to all outcomes of interest but functioned differently in the models. For example, fungal concentration was higher in the presence of natural ventilation, but lower with increased mechanical ventilation. In contrast, CO2 was lower with both ventilation types, and lower with higher outdoor temperature. CONCLUSIONS: Using variables measured during an indoor air quality investigation, predictive models can be constructed which are useful in identifying determinants of bioaerosol and bioeffluent concentrations. Ranges of bioaerosol and bioeffluent concentrations for high occupancy buildings in a coastal temperate zone may differ from guidelines written for other indoor settings and climate zones.

Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma. Since low MHC class II expression is associated with poor survival in DLBCL, we examined whether expression of other components in the MHC class II antigen processing pathway may be important in DLBCL biology. Gamma-interferon-inducible lysosomal thiol reductase (GILT) reduces protein disulfide bonds in the endocytic compartment exposing additional epitopes for class II binding and facilitating antigen presentation. In four independent gene expression profiling cohorts with a total of 585 DLBCL patients, low GILT expression was significantly associated with poor overall survival. In contrast, low expression of MARCH1, an E3 ligase that regulates class II trafficking, and HLA-DRA, a classical MHC class II gene, were associated with poor survival in one of four cohorts. The association of low GILT expression with poor survival is independent of established clinical and molecular prognostic factors, the International Prognostic Index and cell of origin classification, respectively. GILT protein expression was detected in both tumor cells and tumor-infiltrating antigen presenting cells. These studies demonstrate that GILT expression levels correlate with clinical outcome and underscore that antigen processing is critical to patient survival in DLBCL.

Clonal deletion of thymocytes with high avidity for self-peptide:MHC complexes is critical for the maintenance of tolerance and prevention of autoimmunity. We have shown that gamma-interferon-inducible lysosomal thiol reductase (GILT) is required for thymic deletion of T cells specific for a self and melanoma Ag, tyrosinase-related protein 1 (TRP1). To define GILT’s role in central tolerance, we show that GILT expression is enriched in thymic APC capable of mediating deletion, medullary thymic epithelial cells (mTEC) and dendritic cells. TRP1 expression is restricted to mTEC. GILT facilitates the MHC class II-restricted presentation of endogenous TRP1 by pooled thymic APC (TEC and bone marrow (BM)-derived APC). Using BM chimeras, we show that TRP1-specific T cells are deleted in chimeras in which GILT is expressed in both TEC and BM-derived APC or GILT expression is restricted to TEC, indicating that GILT expression in TEC is sufficient for deletion of TRP1-specific thymocytes. In contrast, a large number of TRP1-specific T cells develop in chimeras which lack GILT expression in both TEC and BM-derived APC. Chimeras in which GILT expression is limited to BM-derived APC have intermediate levels of TRP1-specific T cells, demonstrating that GILT expression in TEC is required for efficient deletion of TRP1-specific thymocytes. These findings suggest that GILT operates in mTEC to facilitate the presentation of tissue-specific self Ag and promote deletion of autoreactive T cells.

Maintaining tolerance to skin-restricted antigens is critical for avoiding cutaneous autoimmunity. We have shown that gamma-interferon-inducible lysosomal thiol reductase (GILT) is essential for efficient MHC class II-restricted processing of the melanocyte differentiation antigen, tyrosinase-related protein 1 (TRP1). In GILT-/- TRP1-specific TCR transgenic (Tg) mice, CD4+ TRP1-specific T cells escape thymic deletion, but do not induce autoimmune destruction of melanocytes (vitiligo). GILT-/- Tg mice have fewer peripheral CD4+ TRP1-specific T cells compared to TRP1-deficient mice. CD4+ T cells in GILT-/- Tg mice have marked reduced IL-2 and IFN-γ production and a portion are antigen-experienced. Since tolerance is only partially mediated by an increased percentage of TRP1-specific regulatory T cells in GILT-/- mice, we sought to characterize other mechanisms that constrain the activity of TRP1-specific T cells, such as anergy, exhaustion and deletion. Here, we demonstrate that fewer TRP1-specific T cells were recovered from skin-draining lymph nodes following adoptive transfer of CD4+ T cells from GILT-/- Tg compared to TRP1-deficient Tg mice. Furthermore, TRP1-specific T cells from GILT-/- Tg mice underwent diminished antigen-specific proliferation in vitro compared to T cells from TRP1-deficient Tg mice. These findings suggest multiple peripheral tolerance mechanisms inhibit CD4+ T cell mediated autoimmunity to an endogenously expressed cutaneous autoantigen.

Regulating the balance between T cell activation and tolerance is essential for stimulating an anti-tumor immune response and in controlling autoimmunity. We have shown that gamma-interferon-inducible lysosomal thiol reductase (GILT) is required for efficient MHC class II-restricted processing of an epitope from the melanoma antigen tyrosinase-related protein 1 (TRP1). Using CD4+ TRP1-specific T cell receptor transgenic mice, here we demonstrate a novel function for GILT in the regulation of TRP1-specific T cell tolerance. TRP1-specific T cells are centrally deleted in mice expressing both GILT and TRP1 on the RAG-/- background. In contrast, CD4+ T cells develop in the absence of either GILT or TRP1. GILT’s role in central tolerance is supported by GILT and TRP1 expression in thymic stromal cells. Although TRP1-specific CD4+ T cells escape thymic deletion in the absence of GILT, they are tolerant to TRP1 and do not induce vitiligo. TRP1-specific T cells from GILT-deficient mice initially divide in response to antigen, but fail to produce substantial levels of IFN-γ and IL-2. Tolerance is partially mediated by CD25+Foxp3+ regulatory T (Treg) cells. There is an increased percentage of TRP1-specific Treg cells in GILT-deficient compared to TRP1-deficient mice, and Treg cell depletion allows GILT-deficient TRP1-specific CD4+ T cells to induce vitiligo. These studies highlight a critical role for GILT in shaping the CD4+ T cell repertoire.

SUMMARY: Two IgM monoclonal antibodies, MB32 and MB34 specific for meningococcal polysaccharide group B have been raised. Both were detectable by radioimmunoassay and agglutination, but only MB34 was effective in counter immunoelectrophoresis and complement fixation. MB34 was also far more potent than MB32 when tested for passive protection of mice infected with either Neisseria meningitidis group B or Escherichia coli K1. These data demonstrate that group B-specific antibodies do play a protective role in mice infected with these bacteria.