Antigen stimulates glycoprotein secretion and alters ion fluxes in sheep trachea

1983 ◽  
Vol 55 (5) ◽  
pp. 1593-1602 ◽  
Author(s):  
R. J. Phipps ◽  
S. M. Denas ◽  
A. Wanner
Keyword(s):  
Ascaris Suum ◽  
Specific Antigen ◽  
Ion Fluxes ◽  
Mucus Hypersecretion ◽  
Specific Effects ◽  
Nonspecific Effects ◽  
Protein X ◽  
Glycoprotein Secretion ◽  
Airway Cells

We studied the effects of in vitro challenge with specific antigen (Ascaris suum antigen) on glycoprotein secretion and ion fluxes in tracheal tissues from allergic sheep. We mounted tissues in Perspex chambers and measured secretion of 35S- and 3H-labeled glycoproteins and fluxes of Cl- and Na+. In tissues from allergic sheep, A. suum antigen (25 micrograms protein X ml-1) increased glycoprotein secretion. A. suum antigen initially reversed net Cl- flux, causing net absorption of Cl- and of Na+. This was followed 15-30 min later by net secretion of Cl- and of Na+. Pretreatment of tissues with cromolyn (10(-4) M) greatly reduced the effects of A. suum antigen but did not abolish them. The cromolyn-resistant effects were nonspecific, because they were similar to those of in vitro challenges with nonspecific proteins, ovalbumin and ragweed in allergic sheep, and A. suum antigen in nonallergic sheep. We conclude that challenge with A. suum antigen results in mucus hypersecretion in airways of allergic sheep, by both specific and smaller nonspecific effects. Specific effects (cromolyn sensitive) are produced by mediators which are released from airway cells in response to A. suum challenge.

Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer’s Disease

2020 ◽  
Vol 17 (2) ◽  
pp. 141-157 ◽  
Author(s):  
Dubravka S. Strac ◽  
Marcela Konjevod ◽  
Matea N. Perkovic ◽  
Lucija Tudor ◽  
Gordana N. Erjavec ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Large Scale ◽  
Therapeutic Potential ◽  
Relevant Literature ◽  
Comprehensive Overview ◽  
Brain Functions ◽  
Specific Effects ◽  
And Behavior

Background: Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer’s disease. Objective: The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer’s disease. Method: PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. Results: We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer’s disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. Conclusion: Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer’s disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.

Nonspecific effects of the gap junction blocker mefloquine on fast hippocampal network oscillations in the adult rat in vitro

Neuroscience ◽  
2011 ◽  
Vol 192 ◽  
pp. 11-19 ◽  
Author(s):  
C.J. Behrens ◽  
R. ul Haq ◽  
A. Liotta ◽  
M.L. Anderson ◽  
U. Heinemann
Keyword(s):  
Gap Junction ◽  
Adult Rat ◽  
Network Oscillations ◽  
Nonspecific Effects ◽  
Hippocampal Network

scholarly journals HETEROGENEITY OF ANTIBODY-FORMING CELLS

1969 ◽  
Vol 129 (5) ◽  
pp. 1029-1044 ◽  
Author(s):  
Cesare Bosman ◽  
Joseph D. Feldman ◽  
Edgar Pick
Keyword(s):  
Lymph Nodes ◽  
Plasma Cells ◽  
Specific Antigen ◽  
Cell Suspensions ◽  
Electron Microscopic ◽  
Cytoplasmic Vacuoles ◽  
Draining Lymph Nodes

Cell suspensions from draining lymph nodes of immune and nonimmune rats were reacted in vitro with 125I-labeled antigens. In light microscopic radioautographs of smears, 17% of the immunized cells were tagged by specific antigen; 2.0% of control cells were positive. In electron microscopic radioautographs, 90% of the labeled elements from immune donors were lymphocytes, blast and plasma cells; 10% were monocytes-macrophages or other elements, including naked nuclei. 15% of the labeled cells from control materials were lymphocytes and plasma cells, while 85% were monocytes-macrophages and naked nuclei. Within cell suspensions derived from immunized animals there were almost twice as many lymphocytes marked by isotope as plasma cells, and the lymphocytes ranged in morphology from mature monoribosomal elements to immature polyribosomal cells. Antibody-forming cells fixed labeled antigen at their surfaces. The monocyte-macrophage class was distinguished by a high mean grain count and by distribution of grains within cytoplasmic vacuoles and lysosomes.

Conjugation of an antibody Fv fragment to a virus coat protein: cell-specific targeting of recombinant polyoma-virus-like particles

2001 ◽  
Vol 356 (3) ◽  
pp. 867-873 ◽  
Author(s):  
Kay STUBENRAUCH ◽  
Stefan GLEITER ◽  
Ulrich BRINKMANN ◽  
Rainer RUDOLPH ◽  
Hauke LILIE
Keyword(s):  
Coat Protein ◽  
Mammalian Cells ◽  
Recombinant Antibody ◽  
Specific Antigen ◽  
Antibody Fragment ◽  
Fusion Peptides ◽  
Virus Like Particles ◽  
Vector Systems ◽  
Virus Coat

The development of cell-type-specific delivery systems is highly desirable for gene-therapeutic applications. Current virus-based vector systems show broad cell specificity, which results in the need to restrict the natural tropism of these viral systems. Here we demonstrate that tumour-cell-specific virus-like particles can be functionally assembled in vitro from recombinant viral coat protein expressed in Escherichia coli. The insertion of a negatively charged peptide in the HI loop of polyoma VP1 interferes with the binding of VP1 to the natural recognition site on mammalian cells and also serves as an adapter for the coupling of antibody fragments that contain complementary charged fusion peptides. A recombinant antibody fragment of the tumour-specific anti-(Lewis Y) antibody B3 could be coupled to the mutant VP1 by engineered polyionic peptides and an additional disulphide bond. With this system an entirely recombinant cell-specific delivery system assembled in vitro could be generated that transfers genes preferentially to cells presenting the tumour-specific antigen on the cell surface.

Subset-Specific Effects of Sex Hormones and Pituitary Gonadotropins on Human Lymphocyte Proliferation in Vitro

1993 ◽  
Vol 66 (3) ◽  
pp. 201-211 ◽  
Author(s):  
Balu H. Athreya ◽  
Jonathan Pletcher ◽  
Francesco Zulian ◽  
David B. Weiner ◽  
William V. Williams
Keyword(s):  
Sex Hormones ◽  
Human Lymphocyte ◽  
Lymphocyte Proliferation ◽  
Specific Effects ◽  
Proliferation In Vitro

scholarly journals Interleukin 12 induces stable priming for interferon gamma (IFN-gamma) production during differentiation of human T helper (Th) cells and transient IFN-gamma production in established Th2 cell clones.

1994 ◽  
Vol 179 (4) ◽  
pp. 1273-1283 ◽  
Author(s):  
R Manetti ◽  
F Gerosa ◽  
M G Giudizi ◽  
R Biagiotti ◽  
P Parronchi ◽  
...  
Keyword(s):  
T Cells ◽  
Interferon Gamma ◽  
Specific Antigen ◽  
Th2 Cells ◽  
Interleukin 12 ◽  
T Helper ◽  
Ifn Gamma ◽  
Selection Of

Interleukin 12 (IL-12) facilitates the generation of a T helper type 1 (Th1) response, with high interferon gamma (IFN-gamma) production, while inhibiting the generation of IL-4-producing Th2 cells in polyclonal cultures of both human and murine T cells and in vivo in the mouse. In this study, we analyzed the effect of IL-12, present during cloning of human T cells, on the cytokine profile of the clones. The culture system used allows growth of clones from virtually every T cell, and thus excludes the possibility that selection of precommitted Th cell precursors plays a role in determining characteristics of the clones. IL-12 present during the cloning procedures endowed both CD4+ and CD8+ clones with the ability to produce IFN-gamma at levels severalfold higher than those observed in clones generated in the absence of IL-12. This priming was stable because the high levels of IFN-gamma production were maintained when the clones were cultured in the absence of IL-12 for 11 d. The CD4+ and some of the CD8+ clones produced variable amounts of IL-4. Unlike IFN-gamma, IL-4 production was not significantly different in clones generated in the presence or absence of IL-12. These data suggest that IL-12 primes the clone progenitors, inducing their differentiation to high IFN-gamma-producing clones. The suppression of IL-4-producing cells observed in polyclonally generated T cells in vivo and in vitro in the presence of IL-12 is not observed in this clonal model, suggesting that the suppression depends more on positive selection of non-IL-4-producing cells than on differentiation of individual clones. However, antigen-specific established Th2 clones that were unable to produce IFN-gamma with any other inducer did produce IFN-gamma at low but significant levels when stimulated with IL-12 in combination with specific antigen or insoluble anti-CD3 antibodies. This induction of IFN-gamma gene expression was transient, because culture of the established clones with IL-12 for up to 1 wk did not convert them into IFN-gamma producers when stimulated in the absence of IL-12. These results suggest that Th clones respond to IL-12 treatment either with a stable priming for IFN-gamma production or with only a transient low level expression of the IFN-gamma gene, depending on their stage of differentiation.

scholarly journals Specific and Nonspecific Effects of Protein Kinase C on the Epithelial Na + Channel

2000 ◽  
Vol 115 (5) ◽  
pp. 559-570 ◽  
Author(s):  
Mouhamed S. Awayda
Keyword(s):  
Membrane Trafficking ◽  
Expression System ◽  
Na Channel ◽  
Specific Effects ◽  
Nonspecific Effects ◽  
Oocyte Expression ◽  
Xenopus Oocyte Expression ◽  
Oocyte Expression System ◽  
Baseline Values ◽  
Epithelial Na Channel

The Xenopus oocyte expression system was used to explore the mechanisms of inhibition of the cloned rat epithelial Na+ channel (rENaC) by PKC (Awayda, M.S., I.I. Ismailov, B.K. Berdiev, C.M. Fuller, and D.J. Benos. 1996. J. Gen. Physiol. 108:49–65) and to determine whether human ENaC exhibits similar regulation. Effects of PKC activation on membrane and/or channel trafficking were determined using impedance analysis as an indirect measure of membrane area. hENaC-expressing oocytes exhibited an appreciable activation by hyperpolarizing voltages. This activation could be fit with a single exponential, described by a time constant (τ) and a magnitude (ΔI V). A similar but smaller magnitude of activation was also observed in oocytes expressing rENaC. This activation likely corresponds to the previously described effect of hyperpolarizing voltage on gating of the native Na+ channel (Palmer, L.G., and G. Frindt. 1996. J. Gen. Physiol. 107:35–45). Stimulation of PKC with 100 nM PMA decreased ΔIV in hENaC-expressing oocytes to a plateau at 57.1 ± 4.9% (n = 6) of baseline values at 20 min. Similar effects were observed in rENaC-expressing oocytes. PMA decreased the amiloride-sensitive hENaC slope conductance (gNa) to 21.7 ± 7.2% (n = 6) of baseline values at 30 min. This decrease was similar to that previously reported for rENaC. This decrease of g Na was attributed to a decrease of membrane capacitance (C m), as well as the specific conductance (gm/Cm ). The effects on gm/Cm reached a plateau within 15 min, at ∼60% of baseline values. This decrease is likely due to the specific ability of PKC to inhibit ENaC. On the other hand, the decrease of Cm was unrelated to ENaC and is likely an effect of PKC on membrane trafficking, as it was observed in ENaC-expressing as well as control oocytes. At lower PMA concentrations (0.5 nM), smaller changes of Cm were observed in rENaC- and hENaC-expressing oocytes, and were preceded by larger changes of gm and by changes of gm/Cm, indicating specific effects on ENaC. These findings indicate that PKC exhibits multiple and specific effects on ENaC, as well as nonspecific effects on membrane trafficking. Moreover, these findings provide the electrophysiological basis for assessing channel-specific effects of PKC in the Xenopus oocyte expression system.

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