Although elevated CD4⁺Foxp3⁺ regulatory T cell (Treg) frequencies within tumors are well documented, the functional and phenotypic characteristics of CD4⁺Foxp3⁺ and CD4⁺Foxp3⁻ T cell subsets from ...matched blood, healthy colon, and colorectal cancer require in-depth investigation. Flow cytometry revealed that the majority of intratumoral CD4⁺Foxp3⁺ T cells (Tregs) were Helios⁺ and expressed higher levels of cytotoxic T-lymphocyte antigen 4 (CTLA-4) and CD39 than Tregs from colon and blood. Moreover, ∼30% of intratumoral CD4⁺Foxp3⁻ T cells expressed markers associated with regulatory functions, including latency-associated peptide (LAP), lymphocyte activation gene-3 (LAG-3), and CD25. This unique population of cells produced interleukin-10 (IL-10) and transforming growth factor-β (TGF-β), and was ∼50-fold more suppressive than Foxp3⁺ Tregs. Thus, intratumoral Tregs are diverse, posing multiple obstacles to immunotherapeutic intervention in colorectal malignancies.
Electrostatically formed nanowire (EFN)-based transistors have been suggested in the past as gas sensing devices. These transistors are multiple gate transistors in which the source to drain ...conduction path is determined by the bias applied to the back gate, and two junction-side gates. If a specific bias is applied to the side gates, the conduction band electrons between them are confined to a well-defined area forming a narrow channel-the EFN. By applying a nonsymmetric bias on the side gates, the lateral position of the EFN can be controlled. We propose a novel multiple state EFN transistor (MSET) that utilizes this degree of freedom for the implementation of complete multiplexer functionality in a single device. The basic device functionality was verified through simulation of MSETs with three and four well defined conduction states. The multiplexer functionality allows a very simple implementation of binary and multiple valued logic functions.
Summary
Fluorochrome‐conjugated peptide–major histocompatibility complex (pMHC) multimers are widely used for flow cytometric visualization of antigen‐specific T cells. The most common multimers, ...streptavidin–biotin‐based ‘tetramers’, can be manufactured readily in the laboratory. Unfortunately, there are large differences between the threshold of T cell receptor (TCR) affinity required to capture pMHC tetramers from solution and that which is required for T cell activation. This disparity means that tetramers sometimes fail to stain antigen‐specific T cells within a sample, an issue that is particularly problematic when staining tumour‐specific, autoimmune or MHC class II‐restricted T cells, which often display TCRs of low affinity for pMHC. Here, we compared optimized staining with tetramers and dextramers (dextran‐based multimers), with the latter carrying greater numbers of both pMHC and fluorochrome per molecule. Most notably, we find that: (i) dextramers stain more brightly than tetramers; (ii) dextramers outperform tetramers when TCR–pMHC affinity is low; (iii) dextramers outperform tetramers with pMHC class II reagents where there is an absence of co‐receptor stabilization; and (iv) dextramer sensitivity is enhanced further by specific protein kinase inhibition. Dextramers are compatible with current state‐of‐the‐art flow cytometry platforms and will probably find particular utility in the fields of autoimmunity and cancer immunology.
The success of Johne's disease (JD) control programs based on risk assessment (RA) depends on producers’ compliance with suggested management practices. One objective of this study was to describe ...the perception of participating Canadian dairy farmers of the impact of JD, the RA process, and suggested management strategies. The second objective was to describe the cost of changes in management practices following the RA. A telephone survey was conducted with 238 dairy farmers in Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia. The producers agreed to participate in this follow-up study after they had been enrolled in an RA-based voluntary JD control program and had tested their herd with the JD milk ELISA test in 2005 to 2007. The majority of farms had no JD test-positive cows and, although some producers thought they had experienced the economic impact of JD, many did not see JD as a current problem for their herd. The majority of producers enrolled in this program because they were concerned that Mycobacterium avium ssp. paratuberculosis could be perceived by consumers as a cause for Crohn's disease in humans, which could lead to altered purchasing behavior of milk and milk products. Fifty-two farm-specific recommendations had been made after the initial RA. Although the producers generally liked the program and found the recommendations reasonable and feasible, on average only 2 of 6 suggestions made specifically to them were implemented. The recommendation with the highest compliance was culling of JD test-positive cows. The main reasons for noncompliance were that the dairy producer did not believe a change of management practices was necessary or the available barn setting or space did not allow the change. Producers were generally uncomfortable estimating time and monetary expenses for management changes, but found that several suggested management practices actually saved time and money. In addition, 39% of the producers that implemented at least 1 recommendation thought their calf and herd health had improved subsequently. This indicates that the communication of associated benefits needs to be improved to increase the compliance of producers with recommended management practices.
Prototheca spp. are algae that cause incurable acute or chronic mastitis in dairy cows. The aim of this case-control study was the identification of cow- and herd-level risk factors for this unusual ...mastitis pathogen. Aseptically collected composite milk samples from 2,428 milking cows in 23 case and 23 control herds were collected between January and May 2011. A questionnaire was administered to the producers, and cow-level production and demographic data were gathered. In 58 of 64 isolates, Prototheca spp. and Prototheca zopfii genotypes were differentiated using PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. All isolates were identified as Prototheca zopfii genotype 2. The mean within-herd prevalence for Prototheca spp. was 5.1% (range 0.0–12.5%). Case herds had a significantly lower herd-level prevalence of Staphylococcus aureus and a higher prevalence of yeasts than did control herds. The final logistic regression model for herd-level risk factors included use of intramammary injections of a non-intramammary drug odds ratio (OR) = 136.8, the number of different injectable antibiotic products being used (OR = 2.82), the use of any dry cow teat sealant (external OR = 80.0; internal OR = 34.2), and having treated 3 or more displaced abomasums in the last 12 mo OR = 44.7). The final logistic regression model for cow-level risk factors included second or greater lactation (OR = 4.40) and the logarithm of the lactation-average somatic cell count (OR = 2.99). Unsanitary or repeated intramammary infusions, antibiotic treatment, and off-label use of injectable drugs in the udder might promote Prototheca udder infection.
Burnet proposed in the 1950's that the immune system is engaged in identifying and destroying abnormal cancerous cells. This process, termed immune surveillance, has been at the centre of intense ...debate for decades. Results using immunodeficient mice lend support to the immune surveillance hypothesis. We surmised that immune surveillance would be hampered by the inhibitory effect of naturally occurring FoxP3(+) regulatory T cells, a population of T cells shown to be present at an increased frequency in a variety of human tumours. The carcinogen, methylcholanthrene was injected subcutaneously into mice and the steady development of fibrosarcomas was observed over approximately 200 days. These fibrosarcomas were strikingly infiltrated with FoxP3(+) regulatory T cells implying that these cells impinge upon immune-mediated rejection of the tumour. This was confirmed by partial ablation of FoxP3(+) regulatory T-cell activity, which resulted in a marked reduction in tumour incidence. The reduction of tumour incidence was ablated in mice that lacked interferon gamma. These data offer strong support for the concept of immune surveillance and indicate that this process is limited by the inhibitory effect of FoxP3(+) regulatory T cells.
PDF
