Effects of PFOS and cyclophosphamide exposure on immune homeostasis in mice.

Perfluorooctane sulfonic acid (PFOS) is member of a class of molecules with fluorinated carbon chains known as polyfluoroalkyls. PFOS have been used to produce a variety of industry and comsumer uses. However, a significant concern is that it accumulates in the environment, including in animals and humans, and that it is a potential immunosuppressant. Here we analyze immune homeostasis in mice following chronic exposure to PFOS at levels up to those historically found in PFOS manufacturing workers. Mice were exposed to 0.15, 1.5, 15, or 50 µg /kg of PFOS for 28 days, after which, B cells, T cells, and granulocytes from the bone marrow, liver, spleen, lymph nodes, and thymus were evaluated. We find that at these exposures, there was no effect of PFOS on major T- or B-cell populations, macrophages, dendritic cells, basophils, mast cells, eosinophils, neutrophils, serum antibodies or select serum cytokines. By contrast, mice exposed the known immunosuppressant cyclophosphamide, which was given at 40 mg/kg for four days, exhibited depletion of several granulocyte, T- and B-cell populations of the thymus, bone marrow, and spleen, as well as circulating IgM and IgE antibodies. These data indicate that exposures of up to 50 µg /kg of PFOS for 28 days does not affect immune homeostasis in mice.

ITK independent development of Th17 responses during hypersensitivity pneumonitis driven lung inflammation.

T helper 17 (Th17) cells develop in response to T cell receptor signals (TCR) in the presence of specific environments, and produce the inflammatory cytokine IL17A. These cells have been implicated in a number of inflammatory diseases and represent a potential target for ameliorating such diseases. The kinase ITK, a critical regulator of TCR signals, has been shown to be required for the development of Th17 cells. However, we show here that lung inflammation induced by Saccharopolyspora rectivirgula (SR) induced Hypersensitivity pneumonitis (SR-HP) results in a neutrophil independent, and ITK independent Th17 responses, although ITK signals are required for γδ T cell production of IL17A. Transcriptomic analysis of resultant ITK independent Th17 cells suggest that the SR-HP-induced extrinsic inflammatory signals may override intrinsic T cell signals downstream of ITK to rescue Th17 responses in the absence of ITK. These findings suggest that the ability to pharmaceutically target ITK to suppress Th17 responses may be dependent on the type of inflammation.

TCR Signal Strength and Antigen Affinity Regulate CD8+ Memory T Cells.

CD8+ T cells play a critical role in adaptive immunity, differentiating into CD8+ memory T cells that form the basis of protective cellular immunity. Vaccine efficacy is attributed to long-term protective immunity, and understanding the parameters that regulate development of CD8+ T cells is critical to the design of T cell-mediated vaccines. We show in this study using mouse models that two distinct parameters, TCR signal strength (regulated by the tyrosine kinase ITK) and Ag affinity, play important but separate roles in modulating the development of memory CD8+ T cells. Unexpectedly, our data reveal that reducing TCR signal strength along with reducing Ag affinity for the TCR leads to enhanced and accelerated development of CD8+ memory T cells. Additionally, TCR signal strength is able to regulate CD8+ T cell effector cytokine R production independent of TCR Ag affinity. Analysis of RNA-sequencing data reveals that genes for inflammatory cytokines/cytokine receptors are significantly altered upon changes in Ag affinity and TCR signal strength. Furthermore, our findings show that the inflammatory milieu is critical in regulating this TCR signal strength-mediated increase in memory development, as both CpG oligonucleotide treatment or cotransfer of wild-type and Itk-/- T cells eliminates the observed increase in memory cell formation. These findings suggest that TCR signal strength and Ag affinity independently contribute to CD8+ memory T cell development, which is modulated by inflammation, and suggest that manipulating TCR signal strength along with Ag affinity, may be used to tune the development of CD8+ memory T cells during vaccine development.

Tuning T helper cell differentiation by ITK.

CD4+ effector T cells effectuate T cell immune responses, producing cytokines to orchestrate the nature and type of immune responses. The non-receptor tyrosine kinase IL-2 inducible T cell kinase (ITK), a mediator of T cell Receptor signaling, plays a critical role in tuning the development of these effector cells. In this review we discussed the role that signals downstream of ITK, including the Ras/MAPK pathway, play in differentially controlling the differentiation of TH17, Foxp3+ T regulatory (Treg) cells, and Type 1 regulatory T (Tr1) cells, supporting a model of ITK signals controlling a decision point in the effector T cell differentiation process.

Amino acid starvation enhances vaccine efficacy by augmenting neutralizing antibody production.

Specific reduction in the intake of proteins or amino acids (AAs) offers enormous health benefits, including increased life span, protection against age-associated disorders, and improved metabolic fitness and immunity. Cells respond to conditions of AA starvation by activating the amino acid starvation response (AAR). Here, we showed that mimicking AAR with halofuginone (HF) enhanced the magnitude and affinity of neutralizing, antigen-specific antibody responses in mice immunized with dengue virus envelope domain III protein (DENVrEDIII), a potent vaccine candidate against DENV. HF enhanced the formation of germinal centers (GCs) and increased the production of the cytokine IL-10 in the secondary lymphoid organs of vaccinated mice. Furthermore, HF promoted the transcription of genes associated with memory B cell formation and maintenance and maturation of GCs in the draining lymph nodes of vaccinated mice. The increased abundance of IL-10 in HF-preconditioned mice correlated with enhanced GC responses and may promote the establishment of long-lived plasma cells that secrete antigen-specific, high-affinity antibodies. Thus, these data suggest that mimetics of AA starvation could provide an alternative strategy to augment the efficacy of vaccines against dengue and other infectious diseases.

Interleukin-2-Inducible T-Cell Kinase Deficiency Impairs Early Pulmonary Protection Against Mycobacterium tuberculosis Infection.

Interleukin-2 (IL-2) inducible T-cell kinase (ITK) is a non-receptor tyrosine kinase highly expressed in T-cell lineages and regulates multiple aspects of T-cell development and function, mainly through its function downstream of the T-cell receptor. Itk deficiency can lead to CD4 lymphopenia and Epstein-Bar virus (EBV)-associated lymphoproliferation and recurrent pulmonary infections in humans. However, the role of the ITK signaling pathway in pulmonary responses in active tuberculosis due to Mtb infection is not known. We show here that human lungs with active tuberculosis exhibit altered T-cell receptor/ITK signaling and that Itk deficiency impaired early protection against Mtb in mice, accompanied by defective development of IL-17A-producing γδ T cells in the lungs. These findings have important implications of human genetics associated with susceptibility to Mtb due to altered immune responses and molecular signals modulating host immunity that controls Mtb activity. Enhancing ITK signaling pathways may be an alternative strategy to target Mtb infection, especially in cases with highly virulent strains in which IL-17A plays an essential protective role.

Tpl2 promotes neutrophil trafficking, oxidative burst, and bacterial killing.

Tumor progression locus 2 (Tpl2) is a serine/threonine kinase that promotes inflammatory cytokine production by activating the MEK/ERK pathway. Tpl2 has been shown to be important for eliciting the inflammatory properties of macrophages; however, there is relatively little known about the contribution of Tpl2 to neutrophil effector functions. This is an important consideration, as neutrophils provide the first line of defense against infection in the innate immune system. We found that Tpl2 is expressed in both human and murine neutrophils, suggesting a potential function for Tpl2 in this lineage. Despite significantly higher proportions of bone marrow (BM) neutrophils in Tpl2-deficient (Tpl2-/- ) mice compared with wild-type (WT) mice, Tpl2-/- mice have significantly reduced proportions of circulating neutrophils. Tpl2-/- neutrophils show impaired recruitment to thioglycollate, which was primarily a result of neutrophil-extrinsic factors in the host. In response to infection, neutrophils secrete inflammatory cytokines and produce reactive oxygen species (ROS), which promote bacterial killing. Tpl2 ablation impaired neutrophil TNF secretion in response to LPS stimulation, superoxide generation in response to the chemotactic peptide fMLP, and killing of the extracellular bacterium, Citrobacter rodentium, despite normal bacterial phagocytosis. These results implicate Tpl2 in the regulation of multiple neutrophil antimicrobial pathways, including inflammatory cytokine secretion and oxidative burst. Furthermore, they indicate that Tpl2 functions early during infection to bolster neutrophil-mediated innate immunity against extracellular bacteria.

Interventions for the Reduction of Dental Anxiety and Corresponding Behavioral Deficits in Children with Autism Spectrum Disorder.

PURPOSE: Autism Spectrum Disorder (ASD) can greatly inhibit a child's communication and social interaction skills, impacting their comfort during dental hygiene treatment and services. Children with ASD may exhibit sensory sensitivities, fear of the unfamiliar and lack of socio-cognitive understanding, leading to anxiety and corresponding behavioral deficits. Since the prevalence rates for ASD have risen significantly in the past decade, increased emphasis has been placed on educational and behavior guidance techniques, which can be helpful for children with ASD because of their increased capabilities in visual-processing. The purpose of this literature review is to summarize the interventions available to reduce dental anxiety in children with ASD, and to determine which strategies are best suited for implementation by the dental hygienist. Advancements in technology and socio-behavioral interventions were assessed for appropriate use, efficacy and engagement in the target population. Interventions were categorized into the following groups: picture cards, video technologies and mobile applications.

More lipophilic dialkyldiamine-based diazeniumdiolates: synthesis, characterization, and application in preparing thromboresistant nitric oxide release polymeric coatings.

The synthesis, characterization, and biomedical application in preparing more thromboresistant polymeric coatings for a series of lipophilic dialkyldiamine-based diazeniumdiolatesare described. Dialkylhexamethylenediamine diazeniumdiolates of the form RN[N(O)NO](-)(CH(2))(6)NH(2)(+)R, where R = CH(3), CH(2)CH(3), (CH(2))(2)CH(3), (CH(2))(3)CH(3), (CH(2))(4)CH(3,) (CH(2))(5)CH(3), and (CH(2))(11)CH(3), are prepared via reaction of the corresponding diamine with NO. The more lipophilic diazeniumdiolates [e.g., R = (CH(2))(3)CH(3)] can be incorporated into hydrophobic polymeric films (e.g., plasticized PVC), and the resulting materials release NO for extended periods of time upon exposure to PBS buffer. The mechanism of NO release from these films is examined in detail. More stable initial NO release can be achieved by adding lipophilic anionic species (e.g., tetraphenylborate derivative) to the polymeric material to buffer the activity of protons within the organic phase. It is shown that the use of these new lipophilic NO-donors in polymers provides the ability to tailor NO release rates for a variety of medical applications. As an example, polymers doped with N,N'-dibutylhexamethylenediamine diazeniumdiolate and a tetraphenylborate derivative are employed as coatings for vascular grafts in sheep. The NO release grafts exhibited enhanced performance and had an average 95% thrombus-free surface area compared to 42% for the corresponding control grafts when examined after 21d of implantation.