T helper cell subsets specific for pseudomonas aeruginosa in healthy individuals and patients with cystic fibrosis

Background: We set out to determine the magnitude of antigen-specific memory T helper cell responses to Pseudomonas aeruginosa in healthy humans and patients with cystic fibrosis. Methods: Peripheral blood human memory CD4+ T cells were co-cultured with dendritic cells that had been infected with different strains of Pseudomonas aeruginosa. The T helper response was determined by measuring proliferation, immunoassay of cytokine output, and immunostaining of intracellular cytokines. Results: Healthy individuals and patients with cystic fibrosis had robust antigen-specific memory CD4+ T cell responses to Pseudomonas aeruginosa that not only contained a Th1 and Th17 component but also Th22 cells. In contrast to previous descriptions of human Th22 cells, these Pseudomonal-specific Th22 cells lacked the skin homing markers CCR4 or CCR10, although were CCR6+. Healthy individuals and patients with cystic fibrosis had similar levels of Th22 cells, but the patient group had significantly fewer Th17 cells in peripheral blood. Conclusions: Th22 cells specific to Pseudomonas aeruginosa are induced in both healthy individuals and patients with cystic fibrosis. Along with Th17 cells, they may play an important role in the pulmonary response to this microbe in patients with cystic fibrosis and other conditions

Signaling pathways downstream of P2 receptors in human neutrophils

Extracellular nucleotides stimulate human neutrophils by activating the purinergic P2Y2 receptor. However, it is not completely understood which types of G proteins are activated downstream of this P2 receptor subtype. We investigated the G-protein coupling to P2Y2 receptors and several subsequent signaling events. Treatment of neutrophils with pertussis toxin (PTX), a Gi protein inhibitor, caused only ∼75% loss of nucleotide-induced Ca2+ mobilization indicating that nucleotides cause Ca2+ mobilization both through Gi-dependent and Gi-independent pathways. However, the PLC inhibitor U73122 almost completely inhibited Ca2+ mobilization in both nucleotide- and fMLP-stimulated neutrophils, strongly supporting the view that both the PTX-sensitive and the PTX-insensitive mechanism of Ca2+ increase require activation of PLC. We investigated the dependence of ERK phosphorylation on the Gi pathway. Treatment of neutrophils with PTX caused almost complete inhibition of ERK phosphorylation in nucleotide or fMLP activated neutrophils. U73122 caused inhibition of nucleotide- or fMLP-stimulated ERK phosphorylation, suggesting that although pertussis toxin-insensitive pathways cause measurable Ca2+ mobilization, they are not sufficient for causing ERK phosphorylation. Since PLC activation leads to intracellular Ca2+ increase and PKC activation, we investigated if these intracellular events are necessary for ERK phosphorylation. Exposure of cells to the Ca2+ chelator BAPTA had no effect on nucleotide- or fMLP-induced ERK phosphorylation. However, the PKC inhibitor GF109203X was able to almost completely inhibit nucleotide- or fMLP-induced ERK phosphorylation. We conclude that the P2Y2 receptor can cause Ca2+ mobilization through a PTX-insensitive but PLC-dependent pathway and ERK phosphorylation is highly dependent on activation of the Gi proteins

Leukocytes Are Recruited through the Bronchial Circulation to the Lung in a Spontaneously Hypertensive Rat Model of COPD

Chronic obstructive pulmonary disease (COPD) kills approximately 2.8 million people each year, and more than 80% of COPD cases can be attributed to smoking. Leukocytes recruited to the lung contribute to COPD pathology by releasing reactive oxygen metabolites and proteolytic enzymes. In this work, we investigated where leukocytes enter the lung in the early stages of COPD in order to better understand their effect as a contributor to the development of COPD. We simultaneously evaluated the parenchyma and airways for neutrophil accumulation, as well as increases in the adhesion molecules and chemokines that cause leukocyte recruitment in the early stages of tobacco smoke induced lung disease. We found neutrophil accumulation and increased expression of adhesion molecules and chemokines in the bronchial blood vessels that correlated with the accumulation of leukocytes recovered from the lung. The expression of adhesion molecules and chemokines in other vascular beds did not correlate with leukocytes recovered in bronchoalveolar lavage fluid (BALF). These data strongly suggest leukocytes are recruited in large measure through the bronchial circulation in response to tobacco smoke. Our findings have important implications for understanding the etiology of COPD and suggest that pharmaceuticals designed to reduce leukocyte recruitment through the bronchial circulation may be a potential therapy to treat COPD

Evaluating teaching effectiveness in nursing education:An Iranian perspective

BACKGROUND: The main objective of this study was to determine the perceptions of Iranian nurse educators and students regarding the evaluation of teaching effectiveness in university-based programs. METHODS: An exploratory descriptive design was employed. 143 nurse educators in nursing faculties from the three universities in Tehran, 40 undergraduate, and 30 graduate students from Tehran University composed the study sample. In addition, deans from the three nursing faculties were interviewed. A researcher-developed questionnaire was used to determine the perceptions of both faculty and students about evaluating the teaching effectiveness of nurse educators, and an interview guide was employed to elicit the views of deans of faculties of nursing regarding evaluation policies and procedures. Data were analyzed using parametric and nonparametric statistics to identify similarities and differences in perceptions within the Iranian nurse educator group and the student group, and between these two groups of respondents. RESULTS: While faculty evaluation has always been a major part of university based nursing programs, faculty evaluation must be approached more analytically, objectively, and comprehensively to ensure that all nursing educators receive the fairest treatment possible and that the teaching-learning process is enhanced. CONCLUSION: Educators and students stressed that systematic and continuous evaluation as well as staff development should be the primary goals for the faculty evaluation process. The ultimate goals is the improvement of teaching by nurse educators

Effects of Intracellular Calcium and Actin Cytoskeleton on TCR Mobility Measured by Fluorescence Recovery

Background: The activation of T lymphocytes by specific antigen is accompanied by the formation of a specialized signaling region termed the immunological synapse, characterized by the clustering and segregation of surface molecules and, in particular, by T cell receptor (TCR) clustering. Methodology/Principal Findings: To better understand TCR motion during cellular activation, we used confocal microscopy and photo-bleaching recovery techniques to investigate the lateral mobility of TCR on the surface of human T lymphocytes under various pharmacological treatments. Using drugs that cause an increase in intracellular calcium, we observed a decrease in TCR mobility that was dependent on a functional actin cytoskeleton. In parallel experiments measurement of filamentous actin by FACS analysis showed that raising intracellular calcium also causes increased polymerization of the actin cytoskeleton. These in vitro results were analyzed using a mathematical model that revealed effective binding parameters between TCR and the actin cytoskeleton. Conclusion/Significance: We propose, based on our results, that increase in intracellular calcium levels leads to actin polymerization and increases TCR/cytoskeleton interactions that reduce the overall mobility of the TCR. In a physiological setting, this may contribute to TCR re-positioning at the immunological synapse

Extravasation of leukocytes in comparison to tumor cells

The multi-step process of the emigration of cells from the blood stream through the vascular endothelium into the tissue has been termed extravasation. The extravasation of leukocytes is fairly well characterized down to the molecular level, and has been reviewed in several aspects. Comparatively little is known about the extravasation of tumor cells, which is part of the hematogenic metastasis formation. Although the steps of the process are basically the same in leukocytes and tumor cells, i.e. rolling, adhesion, transmigration (diapedesis), the molecules that are involved are different. A further important difference is that leukocyte interaction with the endothelium changes the endothelial integrity only temporarily, whereas tumor cell interaction leads to an irreversible damage of the endothelial architecture. Moreover, tumor cells utilize leukocytes for their extravasation as linkers to the endothelium. Thus, metastasis formation is indirectly susceptible to localization signals that are literally specific for the immune system. We herein compare the extravasation of leukocytes and tumor cells with regard to the involved receptors and the localization signals that direct the cells to certain organs and sites of the body