Absence Of Prior Sensitization Research Articles

The Adverse Impact of Tumor Microenvironment on NK-Cell.

NK cells are considered an important component of innate immunity, which is the first line of defensing against tumors and viral infections in the absence of prior sensitization. NK cells express an array of germline-encoded receptors, which allow them to eliminate abnormal cells and were previously considered a homogenous population of innate lymphocytes, with limited phenotypic and functional diversity. Although their characteristics are related to their developmental origins, other factors, such as tumors and viral infections, can influence their phenotype. Here, we provide an overview of NK cells in the context of the tumor microenvironment, with a primary focus on their phenotypes, functions, and roles in tumor micro-environment. A comprehensive understanding of NK cells in the tumor microenvironment will provide a theoretical basis for the development of NK cell immunotherapy.

Evaluation of Functional NK Cell Responses in Vaccinated and SIV-Infected Rhesus Macaques.

NK cells are crucial components of the innate immune system due to their capacity to exert rapid cytotoxic and immunomodulatory function in the absence of prior sensitization. NK cells can become activated by exposure to target cells and/or by cytokines produced by antigen-presenting cells. In this study, we examined the effects of a simian immunodeficiency virus (SIV) vaccine regimen and subsequent SIV infection on the cytotoxic and immunomodulatory functions of circulatory NK cells. While vaccination did not significantly impact the capacity of NK cells to kill MHC-devoid 721.221 target cells, SIV-infection led to a significant decrease in target cell killing. NK cells from uninfected macaques were responsive to a low dose (5 ng/ml) of IL-15 pre-activation, leading to significant increases in their cytotoxic potential, however, NK cells from SIV-infected macaques required a higher dose (50 ng/ml) of IL-15 pre-activation in order to significantly increase their cytotoxic potential. By contrast, no differences were observed in the capacity of NK cells from vaccinated and SIV-infected macaques to respond to IL-12 and IL-18. Similarly, NK cells both before and after infection exhibited equivalent responses to Fc-mediated activation. Collectively, our results show that early SIV-infection impairs the natural cytotoxic capacity of circulatory NK cells without affecting Fc-mediated or cytokine-producing function.

Purpura thrombopénique induit par la rifampicine chez une patiente non sensibilisée : à propos d’un cas

Thrombocytopenia induced by rifampicin in the absence of prior sensitization is exceptional, especially when it occurs in a patient without risk factors. We report the case of a patient aged 25 years with no past history of medical, surgical or knowledge of having taken rifampicin previously, who was hospitalized for treatment of thrombocytopenic purpura occurring after the initiation of fixed combination quadruple therapy (isoniazid, rifampicin, pyrazinamide and ethambutol) for pulmonary tuberculosis. The biological pretreatment and therapeutic education had not been made. The patient presented with thrombocytopenic purpura 30000/mm(3) on day 9 after the initiation of treatment. The platelet count returned to normal 10 days after discontinuation of treatment. We elected not to reintroduce rifampicin given the strong likelihood that it was responsible for this complication. We conducted a phased reintroduction of isoniazid, ethambutol and pyrazinamide. No recurrence of the thrombocytopenia occurred. Thus, the diagnosis of rifampicin-induced thrombocytopenia appears to have been confirmed and the patient tolerated the remainder of their treatment well.

Reactive Coupling of 4-Vinylaniline with Hydrogen-Terminated Si(100) Surfaces for Electroless Metal and “Synthetic Metal” Deposition

Pristine and resist-patterned Si(100) substrates were etched by aqueous HF to produce hydrogen-terminated silicon (H-Si(100)) surfaces. The H-Si(100) surface was then subjected to UV-induced reactive coupling of 4-vinylaniline (VAn) to produce the VAn monolayer-modified silicon (VAn-Si) surface. The VAn-Si surface was first functionalized with a "synthetic metal" by oxidative graft polymerization of aniline with the aniline moieties of the coupled VAn molecules. The composition and topography of the VAn-Si and polyaniline (PAn)-grafted VAn-Si (PAn-VAn-Si) surfaces were characterized by X-ray photoelectron spectroscopy and atomic force microscopy, respectively. The doping-undoping (protonation-deprotonation) and redox-coupling (metal reduction) behavior, as well as the electrical conductivity, of the surface-grafted PAn were found to be similar to those of the aniline homopolymer. The VAn-Si surface was also funtionalized by the electroless plating of copper. Not only did the VAn layer provide chemisorption sites for the palladium catalyst, in the absence of prior sensitization by SnCl2, during the electroless plating process, it also served as an adhesion promotion layer and a low-temperature diffusion barrier for the electrolessly deposited copper. Finally, micropatterning of the grafted PAn and of the electrolessly deposited copper were demonstrated on the resist-patterned VAn-Si surfaces.

Electroless Plating of Copper via a Sn-Free Process on Dielectric SiLK Surface Modified by UV-Induced Graft Copolymerization with 4-Vinylpyridine and 1-Vinylimidazole

Surface modification of Ar plasma-pretreated SiLK film coating on a (100)-oriented silicon wafer (SiLK-Si substrate) via UV-induced graft copolymerization with 4-vinylpyridine (the 4VP-g-SiLK-Si surface) or 1-vinylimidazole (the VIDz-g-SiLK-Si surface) was carried out to promote the adhesion with the electrolessly deposited copper. The surface composition of the graft-copolymerized SiLK-Si substrates was characterized by X-ray photoelectron spectroscopy. The topography of the 4VP-g-SiLK-Si and VIDz-g-SiLK-Si surfaces was investigated by atomic force microscopy. The 4VP-g-SiLK-Si and VIDz-g-SiLK-Si surfaces could be activated by in the absence of prior sensitization by (the Sn-free activation process) for the subsequent electroless deposition of copper. The 180°-peel adhesion strength of the electrolessly deposited copper on the 4VP-g-SiLK-Si and VIDz-g-SiLK-Si surfaces reaches about 6 and 5 N/cm, respectively. These adhesion strength values were much higher than those of the electrolessly deposited copper on the pristine and Ar plasma-treated SiLK-Si surfaces. The strong adhesion of the electrolessly deposited copper to the VIDz-g-SiLK-Si and 4VP-g-SiLK-Si surfaces was attributed to the synergistic effect of the strong interaction between the pyridine or imidazole functional groups of the grafted polymers with copper atoms, the spatial distribution of the graft chains on the SiLK surface and into the metal matrix, and the fact that the graft chains were covalently tethered on the SiLK surface. © 2002 The Electrochemical Society. All rights reserved.

Electroless plating of copper on polyimide films modified by surface grafting of tertiary and quaternary amines polymers

Argon plasma-pretreated polyimide (PI, Kapton ® HN) films were subjected to UV-induced surface graft copolymerization with N, N′-(dimethylamino)ethyl methacrylate (DMAEMA) and 2-(trimethylammonium)ethyl methacrylate chloride (TMMAC). The DMAEMA graft-copolymerized PI (DMAEMA- g-PI) surfaces were also quaternized and amino-functionalized with 3-bromopropylamine hydrobromide (the Q-DMAEMA- g-PI surfaces). The surface composition and the degree of quaternization of the graft-modified PI films were determined by X-ray photoelectron spectroscopy. The DMAEMA- g-PI, Q-DMAEMA- g-PI and TMMAC graft-copolymerized PI (TMMAC- g-PI) surfaces can be activated directly by PdCl 2, in the absence of prior sensitization by SnCl 2 (the ‘Sn-free’ activation process), for the subsequent electroless plating of copper. A shorter induction time for the electroless deposition of copper was found for the palladium-activated Q-DMAEMA- g-PI and TMMAC- g-PI surfaces than for the palladium-activated DMAEMA- g-PI surface. The T-peel adhesion strength of the electrolessly deposited copper with the Q-DMAEMA- g-PI surface was enhanced to above 6 N/cm, in comparison to only about 4 N/cm for the DMAEMA- g-PI surface, about 2.5 N/cm for the TMMAC- g-PI surface, or about 0.5 N/cm for the PI surface with argon plasma treatment alone.

Investigation of humoral immune factors from selected groups of southern bluefin tuna, Thunnus maccoyii (Castelnau): implications for aquaculture

Serum immunoglobulin, lysozyme and classical and alternative complement activity were analysed in different groups of wild and captive southern bluefin tuna (SBT), Thunnus maccoyii (Castelnau), from ambient water temperatures of 12 ± 1 and 20 ± 1 °C. Groups held captive for the longest time were found to have the highest levels of these humoral immune mediators, despite a drop in ambient temperature from 20 ± 1 to 12 ± 1 °C during the captivity period. Therefore, it may be that the immune response in these endothermic fish is not inhibited by low temperature to the extent seen in poikilothermic fish. Also, length of time in captivity appears to be associated with increased antigen exposure to maintain high levels of humoral immune mediators in these groups. Lysozyme activity was optimal at pH 5.8 and 6.2, suggesting that two isoforms, with different pH optima, are present. The SBT serum was found to lyse sheep erythrocytes by both classical and alternative complement pathways. Classical pathway activity occurred in the absence of prior sensitization with antiserum to sheep red blood cells, suggesting that natural antibodies may be present (or lectin or C‐reactive protein mediated activation). Complement activity was relatively resistant to freezing at −20 °C but heating at between 45 and 50 °C for 20 min destroyed all complement activity.

Electroless Deposition of Copper on Poly(tetrafluoroethylene) Films Modified by Plasma-Induced Surface Grafting of Poly(4-vinylpyridine)

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were solution coated with a thin layer of poly(4-vinyl pyridine) (P4VP). Subsequent exposure of the films to argon plasma resulted in the grafting of P4VP on the PTFE films. Electroless plating of copper could be carried out effectively on the P4VP-grafted PTFE (P4VP-g-PTFE) surface after PdCl2 activation and in the absence of SnCl2 sensitization (the Sn-free process). The catalytic processes of the electroless plating of copper in the presence and absence of sensitization by SnCl2 were also compared. The effect of glow discharge conditions on the P4VP concentration and the adhesion strength of the electrolessly deposited copper was investigated. The T-peel adhesion strength of the electrolessly deposited copper with the graft-modified PTFE film was improved in the absence of SnCl2 sensitization and could reach about 3 N/cm. PdCl2 activation and electroless deposition of copper could not be carried out on the pristine or the Ar plasma-treated PTFE surface in the absence of prior sensitization by SnCl2. X-ray photoelectron spectroscopic (XPS) analysis revealed that the electrolessly deposited copper delaminated from the P4VP-g-PTFE film by cohesive failure inside the PTFE film.

Electroless Plating of Copper on Poly(tetrafluoroethylene) Films Modified by Surface Graft Copolymerization and Quaternization

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were subjected to UV-induced surface graft copolymerization with a tertiary amine monomer, -(dimethylamino)ethyl methacrylate (DMAEMA). The DMAEMA graft-copolymerized PTFE (DMAEMA-g-PTFE) surface was further reacted with 3-bromopropylamine hydrobromide (3-BPAH) to introduce the and the quaternary amine groups on the DMAEMA-g-PTFE film (the Q-DMAEMA-g-PTFE film). Both types of the PTFE surfaces could be activated by direct immersion in solution, in the absence of prior sensitization by (the Sn-free activation process). Electroless plating of copper could be carried out effectively on the Pd-activated DMAEMA-g-PTFE and Q-DMAEMA-g-PTFE surfaces. A much shorter induction time for the electroless plating of copper was found for the Q-DMAEMA-g-PTFE surface than for the DMAEMA-g-PTFE surface. The surface composition and the degree of quaternization of the surface-modified PTFE films were determined by X-ray photoelectron spectroscopy. The T-peel adhesion strength of the electrolessly deposited copper on the Q-DMAEMA-g-PTFE surface was improved to about 8 N/cm, in comparison to only about 4 N/cm for the DMAEMA-g-PTFE surface or about 0.6 N/cm for the PTFE surface with Ar plasma treatment alone. © 2001 The Electrochemical Society. All rights reserved.

Electroless plating of copper on poly(tetrafluoroethylene) films modified by NH3 plasma and surface graft copolymerization with aniline

Electroless plating of copper on poly(tetrafluoroethylene) (PTFE) films modified by NH3 plasma treatment and surface graft copolymerization with aniline had been carried out. For the electroless plating of copper, the polyaniline (PANI)-grafted PTFE (PANI-g-PTFE) surface, with the PANI in its fully reduced leucoemeraldine form, was activated directly in the Pd(NO3)2 acid solution in the absence of prior sensitization by SnCl2. The compositions and chemical states of the PTFE surfaces during each stage of the surface modification, surface activation, and electroless deposition processes were studied by x-ray photoelectron spectroscopy (XPS). The adhesion strength of the electroless deposited copper on the PANI-g-PTFE surface exhibited a strong dependence on the graft concentration of PANI. A T-peel adhesion strength of about 5 N/cm was achieved for the electrolessly deposited Cu on the PANI-g-PTFE surface (the Cu/PANI-g-PTFE assembly). The high adhesion strength of the Cu/PANI-g-PTFE assembly was attributed to the synergistic effects of strong interactions between the grafted aniline polymer and the metal (including Pd) atoms, the spatial distribution of the PANI chains in the metal matrix, and the fact that the polyaniline chains were covalently tethered on the PTFE surface. XPS results also revealed that the Cu/PANI-g-PTFE assemblies delaminated by cohesive failure inside the PTFE film.

Adhesion mediated by LFA-1 is required for efficient IL-12-induced NK and NKT cell cytotoxicity.

Interleukin 12 (IL-12)-activated NK1.1+TCRalpha beta+ (NKT2) and NK1.1+TCRalpha beta- (NK) cells exhibit cytotoxic activity against a wide variety of tumor cells in the absence of prior sensitization. Here we demonstrate that the integrin adhesion receptor LFA-1 (CD11a/CD18) regulates the cytotoxic activity of IL-12-activated NKT and NK cells against YAC-1 and EL-4 tumor cells. Differentiation in vivo and the expression of the cytolytic effector molecules perforin and Fas-L were comparable in both IL-12-activated NKT and NK cells from LFA-1-/ - and LFA-1+/+ mice. However, LFA-1-/-IL-12-activated NKT and NK cells showed impaired conjugate formation with target cells. These results provide the first genetic evidence for a role for an adhesion receptor in killing by IL-12-activated NK cells.

Cooperation Between CD44 and LFA-1/CD11a Adhesion Receptors in Lymphokine-Activated Killer Cell Cytotoxicity

IL-2-activated NK cells exhibit cytotoxic activity against a wide variety of tumor cells in a non-MHC-restricted fashion and in the absence of prior sensitization. The molecular mechanisms that regulate the cytotoxicity and attachment of activated killer cells to tumor target cells are not known. We provide genetic evidence in CD44(-/-) and LFA-1(-/-) mice that the cell adhesion receptors LFA-1 and CD44 regulate the cytotoxic activity of IL-2-activated NK cells against a variety of different tumor cells. This defect in cytotoxicity was significantly enhanced in mice that carried a double mutation of both CD44 and LFA-1. In vitro differentiation, TNF-alpha and IFN-gamma production, and expression of the cytolytic effector molecules perforin and Fas-L were comparable among IL-2-activated NK cells from LFA-1(-/-), CD44(-/-), CD44(-/-)LFA-1(-/-), and control mice. However, CD44(-/-), LFA-1(-/-), and CD44(-/-)LFA-1(-/-) IL-2-activated NK cells showed impaired binding and conjugate formation with target cells. We also show that hyaluronic acid is the principal ligand on tumor cells for CD44-mediated cytotoxicity of IL-2-activated NK cells. These results provide the first genetic evidence of the role of adhesion receptors in IL-2-activated NK killing. These data also indicate that distinct adhesion receptors cooperate to mediate binding between effector and target cells required for the initiation of "natural" cytotoxicity.