1,825 research outputs found

    'Unlicensed' natural killer cells dominate the response to cytomegalovirus infection.

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    Natural killer (NK) cells expressing inhibitory receptors that bind to self major histocompatibility complex (MHC) class I are 'licensed', or rendered functionally more responsive to stimulation, whereas 'unlicensed' NK cells lacking receptors for self MHC class I are hyporesponsive. Here we show that contrary to the licensing hypothesis, unlicensed NK cells were the main mediators of NK cell-mediated control of mouse cytomegalovirus infection in vivo. Depletion of unlicensed NK cells impaired control of viral titers, but depletion of licensed NK cells did not. The transfer of unlicensed NK cells was more protective than was the transfer of licensed NK cells. Signaling by the tyrosine phosphatase SHP-1 limited the proliferation of licensed NK cells but not that of unlicensed NK cells during infection. Thus, unlicensed NK cells are critical for protection against viral infection

    On the Nonparametric Identification of Nonlinear Simultaneous Equations Models: Comment on B. Brown (1983) and Roehrig (1988)

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    This note revisits the identification theorems of B. Brown (1983) and Roehrig (1988). We describe an error in the proofs of the main identification theorems in these papers, and provide an important counterexample to the theorems on the identification of the reduced form. Specifically, contrary to the theorems, the reduced form of a nonseparable simultaneous equations model is not identified even under the assumptions of those papers. We conclude the note with a conjecture that it may be possible to use classical exclusion restrictions to recover some of the key implications of the theorems

    Ly49H signaling through DAP10 is essential for optimal natural killer cell responses to mouse cytomegalovirus infection

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    The activating natural killer (NK) cell receptor Ly49H recognizes the mouse cytomegalovirus (MCMV) m157 glycoprotein expressed on the surface of infected cells and is required for protection against MCMV. Although Ly49H has previously been shown to signal via DAP12, we now show that Ly49H must also associate with and signal via DAP10 for optimal function. In the absence of DAP12, DAP10 enables Ly49H-mediated killing of m157-bearing target cells, proliferation in response to MCMV infection, and partial protection against MCMV. DAP10-deficient Ly49H+ NK cells, expressing only Ly49H–DAP12 receptor complexes, are partially impaired in their ability to proliferate during MCMV infection, display diminished ERK1/2 activation, produce less IFN-γ upon Ly49H engagement, and demonstrate reduced control of MCMV infection. Deletion of both DAP10 and DAP12 completely abrogates Ly49H surface expression and control of MCMV infection. Thus, optimal NK cell–mediated immunity to MCMV depends on Ly49H signaling through both DAP10 and DAP12

    Cancer in Alaska Natives 1969-2003: 35-Year Report

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    Cancer incidence rates for all Alaska Natives (Eskimo, Indian, Aleut) were first reported in 1976. Since then numerous publications have documented the unusual cancer patterns in this population. These are the latest statistics for which there is complete data statewide, and provide the best estimates of cancer incidence in the Alaska Native population. Numbers of new (incident) cases and rates are given for all cancers and for specific sites. These numbers are presented by age, sex, ethnicity, geographic region, and service unit. Data have been collected, tabulated, and analyzed in accordance with procedures established by the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program
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