Browsing by Subject "Neutrophils"
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Item Efficacy of Contact Lens Care Solutions Against Neutrophil Enhanced Biofilms(2015-01-26) Hinojosa, Jorge A.; Patel, Naiya; Zhu, Meifang; Robertson, Danielle M.PURPOSE: To evaluate currently available chemically preserved and peroxide-based lens care products (LCPs) antimicrobial efficacies against neutrophil enhanced biofilms in reference strains of S.auerus(SA), S. marcescens (SM), S. maltophilia(ST), and P.aeruginosa(PA). METHODS: Lotrafilcon B lenses were inoculated with 2.5 x 107 CFUs of American Type Culture Collection (ATCC) reference strains of either SA, SM, ST, or PA and 8.3x106 cells of human neutrophils harvested by whole blood centrifugation. Lenses were then incubated over night under conditions that facilitate biofilm formation. Lenses were then disinfected with either multipurpose contact lens solutions (MPS): Biotrue (BT), PureMoist (PM) or hydrogen peroxide-based lens care systems (HPB): ClearCare (CC), PeroxiClear (PC) according to specific manufacture guidelines. Antimicrobial activity was then quantified by quantitative culturing (colony-forming units) and by fluorescence confocal microscopy (FCM) using LIVE/DEAD BacLight Bacterial Viability Kit (Molecular Probes, Eugene, OR). RESULTS: Mean colony growth counts for each bacterial strain + neutrophils were: SA= 1.44 x 107 (CFU/ml), SM= 2.56x109 (CFU/ml), ST= 1.17x1010 (CFU/ml), PA= 3.43x109 (CFU/ml). After treatment, SA exhibited a 7-log reduction with all LCPs (P=0.609); SM exhibited 9-log reduction for all LCPs except BT, which showed a 7-log reduction (P < 0.001); ST exhibited a 9-log to 10-log reduction for all LCPs (P=0.040); PA showed a 9-log reduction for all LCPs (P=1.000). FCM with viability staining revealed the presence many unviable bacteria still adhered to the lens surface after treatment with LCPs. CONCLUSIONS: Although all LCPs meet FDA criterion of a 3-log reduction minimum even against neutrophil enhanced biofilms, FCM revealed that many remnants still remain adhered on the lens surface after just one use. Further deposition of bacterial products from continued used could enhance biofilm formation and promote a host inflammatory response, both of which could precipitate into a corneal infiltrative event (CIE). In addition, mean colony growth counts showed that SA exhibited the lowest growth on lens surfaces, which may explain why SA is more commonly associated with sterile CIEs.Item Leap, and the NET will appear: a story about antiphospholipid syndrome and COVID-19(2023-06-23) Knight, Jason S.Item Neutrophil-Derived IFN-γ in Toxoplasma gondii Infection and Innate Immunity(2014-11-19) Sturge, Carolyn Rowena; van Oers, Nicolai S. C.; Yuan, Dorothy; Zhang, Chengcheng "Alec"; Koh, Andrew Y.; Yarovinsky, FelixInterferon-gamma (IFN-γ) is a major cytokine that is critical for host resistance to a broad range of intracellular pathogens. Production of IFN-γ by Natural Killer (NK) and T cells is initiated by the recognition of pathogens through Toll-like receptors (TLRs). In an experimental model of toxoplasmosis we have identified the presence of a non-lymphoid source of IFN-γ that was particularly evident in the absence of TLR-mediated recognition of Toxoplasma gondii. Flow-cytometry and morphological examinations of non-NK/non-T IFN-γ-positive cells identified neutrophils as the cell type capable of producing IFN-γ. Selective elimination of neutrophils in TLR11-/- mice infected with the parasite resulted in acute susceptibility similar to that observed in IFN-γ-deficient mice. These data show that neutrophils are a biologically significant source of IFN-γ during T. gondii infection. Additionally, we investigated the role of neutrophil IFN-γ in another intracellular infection, Salmonella typhimurium, and found that neutrophils were also IFN-γ-positive. Examination of neutrophils in different locations in a mouse model revealed that they all expressed low amounts of IFN-γ regardless of infection status. In particular, the bone marrow niche contained an IFN-γ+ population that was negative for the Ly-6G marker characteristic of mature neutrophils in peripheral tissues. Recent work defining neutrophil developmental stages by flow-cytometry allowed us to discern that precursor neutrophils at the promyelocyte stage (Ly-6G negative) were positive for IFN-γ. Furthermore, neutrophil-derived IFN-γ was prestored in granules during neutrophil lineage development although the mechanisms behind this phenomena are not yet understood. This work, combined with the recent work of other laboratories, suggests that neutrophils can have defined phenotypes and cytokine production similar to that of T cells or Innate Lymphoid cells (ILCs). These findings have broad implications for all disease states where neutrophils are the first responders to infections.Item Quantitative Image Analysis in the Study of Neutrophil and Neutrophil-Like HL-60 Chemotaxis(2017-04-11) Zhang-Velten, Elizabeth Ren; Tu, Benjamin; Cobb, Melanie H.; Altschuler, Steven J.; Wu, Lani; Stull, James; Blount, PaulNeutrophils are fast-moving first responders of the innate immune system. External chemoattractant signals result in neutrophil polarization: the neutrophil forms a leading edge (front) which constantly protrudes and retracts actin-rich pseudopods, and a contractile myosin-enriched trailing edge (back) which is insensitive and directionally persistent. Previous work has suggested that polymerized actin and contractile actomyosin segregate to the neutrophil's morphological front and back, respectively, due to mutual inhibition. Beyond this initial establishment of spatially segregated domains, however, many questions remain unclear. In this work, I address two questions: (i) first, how do the front and back of the neutrophil demonstrate seemingly uncoupled behaviors despite these inhibitory links? (ii) and, second, at what fMLP concentration does neutrophil chemotaxis saturate, and how is this maximal concentration determined? With quantitative analysis of immunofluorescent fixed-cell images and live-cell migration videos, I demonstrate the role of microtubules in insulating the front and back modules of chemotactic neutrophils, and the role of ERK in driving neutrophil migration into maximal fMLP concentrations.Item [UT Southwestern Medical Center News](2013-07-10) Wormser, DeborahItem Voluntary Exercise Alters Adaptive Immunity Prior to Injury(2013-01-22) McPartlin, Angelica; Stowe, Anne M.; Poinsatte, Katherine; Mouti, Mariam; Ireland, Sarah J.; Li, MinOBJECTIVE: Exercise provides a neuroprotective role in the setting of cerebral infarct. However, the exact mechanism for this protection is unclear. This study established an exercise preconditioning protocol to test the hypothesis that exercise mediates protection from stroke by altering the immune profile prior to injury to reduce inflammation post-infarct. MATERIALS/METHODS: In our first trial, a three week exercise preconditioning protocol was established using nine C57 mice that endogenously expressed green fluorescent protein (GFP) under the PLP promoter. This biomarker was used to identify oligodendrocyte precursor cells (OPC) to qualify their relationship with voluntary exercise. Exercise activity was recorded and tissues were collected for histological and serological analysis. Analysis of histological sections acquired through Nanozoomer imaging was performed using an unbiased quantification (Stereo Investigator). Ten Swiss Webster (SW) mice with no endogenous fluorescence were used in the subsequent trial. Following sacrifice of the SW mice, samples of the spleen and peripheral blood were collected and analyzed by flow cytometry and microarray was used to analyze resident B cell expression (IPA software). Standard ELISA analysis of peripheral blood was also used for all trials. Significance was determined using t-test or ANOVA. RESULTS: Voluntary exercise in PLP-EGFP mice correlated with a trend increase in OPCs as well as a trend increase in cortical angiogenesis (p=0.06). However, voluntary exercise did not increase hippocampal neuron counts. Voluntary exercise in SW mice showed decreases in percent and raw number of splenic neutrophils and CD8+ T cells (both p<0.01), with a concomitant increase in B cell representation (p<0.05). Peripheral blood samples demonstrated a decrease in percent CD4+ T cells (p<0.01) and decrease in CCL2 (p<0.05) and VEGF (p<0.01) protein. Microarray showed a significant upregulation of 1844 genes and significant downregulation of 1333 genes in the resident splenic B cells of SW exercise mice over the sedentary controls. CONCLUSION: Three weeks of voluntary exercise in mice results in a change in the immune profile prior to an injury occurring. Downregulation of neutrophils, cytotoxic T cells, and CCL2 suggest that this alteration in immunity is anti-inflammatory. Microarray analysis of isolated B cells showed an upregulation of genes associated with lymphocyte maturation and differentiation, with simultaneous downregulation of genes responsible for apoptosis and B cell death. Further studies will determine the significance of these immune adaptations and their mechanistic role in decreased deficits following neurovascular injury.