NK but not CD1-restricted NKT cells facilitate systemic inflammation during polymicrobial intra-abdominal sepsis.

Evidence suggests that NK and NKT cells contribute to inflammation and mortality during septic shock caused by cecal ligation and puncture (CLP). However, the specific contributions of these cell types to the pathogenesis of CLP-induced septic shock have not been fully defined. The goal of the present study was to determine the mechanisms by which NK and NKT cells mediate the host response to CLP. Control, NK cell-deficient, and NKT cell-deficient mice underwent CLP. Survival, cytokine production, and bacterial clearance were measured. NK cell trafficking and interaction with myeloid cells was also studied. Results show that mice treated with anti-asialoGM1 (NK cell deficient) or anti-NK1.1 (NK/NKT cell deficient) show less systemic inflammation and have improved survival compared with IgG-treated controls. CD1 knockout mice (NKT cell deficient) did not demonstrate decreased cytokine production or improved survival compared with wild type mice. Trafficking studies show migration of NK cells from blood and spleen into the inflamed peritoneal cavity where they appear to facilitate the activation of peritoneal macrophages (F4-80(+)GR-1(-)) and F4-80(+)Gr-1(+) myeloid cells. These findings indicate that NK but not CD1-restricted NKT cells contribute to acute CLP-induced inflammation. NK cells appear to mediate their proinflammatory functions during septic shock, in part, by migration into the peritoneal cavity and amplification of the proinflammatory activities of specific myeloid cell populations. These findings provide new insights into the mechanisms used by NK cells to facilitate acute inflammation during septic shock.

Preparation of Au(I), Ag(I), and Pd(II) N-heterocyclic carbene complexes utilizing a methylpyridyl-substituted NHC ligand. formation of a luminescent coordination polymer.

Reaction of the imidazolium N-heterocyclic carbene precursor containing a methyl-substituted pyridyl functionality [HCH3im(CH3py)]PF6, 1, with Ag2O produces the homoleptic Ag(I) complex, [Ag(CH3im(CH3py))2]PF6, 2. In a simple carbene transfer reaction the analogous Au(I) species, [Au(CH3im(CH3py))2]PF6, 3, is formed by treatment of 2 with Au(tht)Cl in dichloromethane. Both 2 and 3 are structurally similar with nearly linearly coordinated NHC ligands. The methyl group appended to the pyridyl ring inhibits rotation of the pyridyl group at room temperature. Addition of AgBF4 to a hot propionitrile solution of 3 followed by crystallization with diethyl ether yields the one-dimensional coordination polymer, {[AuAg(CH3im(CH3py))2(NCCH2CH3)](BF4)2}n, 4, which contains Au-Ag separations of 2.9845(5) and 2.9641(5) A with intermetallic angles of 167.642(14) degrees and 162.081(9) degrees. This material is intensely luminescent in the solid state and exhibits an emission band at 453 nm (lambdaex=350 nm). Nearly colorless [Pd(CH3im(CH3py))2Cl]PF6, 5, is produced upon treatment of 2 with PdCl2(NCC6H5)2. The Pd(II) center in 5 is coordinated to one NHC ligand in a chelate fashion, while the second NHC is bound solely through the carbon center. The X-ray crystal structures of 1-5 are reported.

Pyridine substituted N-heterocyclic carbene ligands as supports for Au(I)-Ag(I) interactions: formation of a chiral coordination polymer.

Reaction of 1,3-bis(2-pyridinylmethyl)-1H-imidazolium tetrafluoroborate, [H(pyCH(2))(2)im]BF(4), with silver oxide in dichloromethane readily yields [Ag((pyCH(2))(2)im)(2)]BF(4), 1.BF(4)(). 1.BF(4) is converted to the analogous Au(I)-containing species, [Au((pyCH(2))(2)im)(2)]BF(4), 3, by a simple carbene transfer reaction in dichloromethane. Further treatment with two equivalents of AgBF(4) produces the trimetallic species [AuAg(2)((pyCH(2))(2)im)(2)(NCCH(3))(2)](BF(4))(3), 4, which contains two silver ions each coordinated to the pyridine moieties on one carbene ligand and to an acetonitrile molecule in a T-shaped fashion. Monometallic [Ag((py)(2)im)(2)]BF(4), 5, and [Au((py)(2)im)(2)]BF(4), 6, are made analogously to 1.BF(4) and 3 starting from 1,3-bis(2-pyridyl)-imidazol-2-ylidene tetrafluoroborate, [H(py)(2)im]BF(4). Addition of excess AgBF(4) to 6 yields the helical mixed-metal polymer, ([AuAg((py)(2)im)(2)(NCCH(3))](BF(4))(2))(n), 7 which contains an extended Au(I)-Ag(I) chain with short metal-metal separations of 2.8359(4) and 2.9042(4) A. Colorless, monometallic [Hg((pyCH(2))(2)im)(2)](BF(4))(2), 8, is easily produced by refluxing [H(pyCH(2))(2)im)]BF(4) with Hg(OAc)(2) in acetonitrile. The related quinolyl-substituted imidazole, [H(quinCH(2))(2)im]PF(6), is produced analogously to [H(pyCH(2))(2)im]BF(4). [Hg((quinCH(2))(2)im)(2)](PF(6))(2), 9, is isolated in good yield as a white solid from the reaction of Hg(OAc)(2) and [H(quinCH(2))(2)im]PF(6). The reaction of [H(quinCH(2))(2)im]PF(6) with excess Ag(2)O produces the triangulo-cluster [Ag(3)((quinCH(2))(2)im)(3)](PF(6))(3), 11. All of these complexes were studied by (1)H NMR spectroscopy, and complexes 3-9 were additionally characterized by X-ray crystallography. These complexes are photoluminescent in the solid state and in solution with spectra that closely resemble those of the ligand precursor.