Induction of anti-tumor CD8 T cell responses by experimental ECP-induced human dendritic antigen presenting cells

Extracorporeal photochemotherapy (ECP), or photopheresis, is distinguished by the specificity of the clinically potent immunologic reactions it initiates or regulates. The selectivity of ECP-induced immunoprotection for the malignant clone in cutaneous T cell lymphoma (CTCL), and for the pathogenic clones in allograft rejection and graft-versus-host disease (GVHD), has suggested a central mechanistic role for dendritic antigen presenting cells (DC). Discovery of ECP's induction of monocyte-derived DC, via monocyte signaling by ECP-plate activated platelets, and the absolute dependency of experimental ECP on such induced DC, supports that premise. Herein, we show that ECP-induced DC are capable of stimulating CD8 T cell responses to tumor antigens with which they are loaded. They internalize an antigen-specific melanoma-associated protein then present it onto a class I major histocompatibility, which then stimulates expansion of anti-tumor CD8 T cell populations. We conclude that ECP-induced DC prominently contribute to its initiation of anti-tumor immunity and raise the possibility that the therapy may be applicable to the immunotherapeutic management of a broader spectrum of cancers.

Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides

The magnetic excitations in the cuprate superconductors might be essential for an understanding of high-temperature superconductivity. In these cuprate superconductors the magnetic excitation spectrum resembles an hour-glass and certain resonant magnetic excitations within are believed to be connected to the pairing mechanism, which is corroborated by the observation of a universal linear scaling of superconducting gap and magnetic resonance energy. So far, charge stripes are widely believed to be involved in the physics of hour-glass spectra. Here we study an isostructural cobaltate that also exhibits an hour-glass magnetic spectrum. Instead of the expected charge stripe order we observe nano phase separation and unravel a microscopically split origin of hour-glass spectra on the nano scale pointing to a connection between the magnetic resonance peak and the spin gap originating in islands of the antiferromagnetic parent insulator. Our findings open new ways to theories of magnetic excitations and superconductivity in cuprate superconductors.

Magnetic-field-induced spin excitations and renormalized spin gap of the underdoped La1.895Sr0.105CuO4 superconductor

High-resolution neutron inelastic scattering experiments in applied magnetic fields have been performed on La1.895Sr0.105CuO4 (LSCO). In zero field, the temperature dependence of the low-energy peak intensity at the incommensurate momentum transfer QIC=(0.5,0.5+/-delta,0),(0.5+/-delta,0.5,0) exhibits an anomaly at the superconducting Tc which broadens and shifts to lower temperature upon the application of a magnetic field along the c axis. A field-induced enhancement of the spectral weight is observed, but only at finite energy transfers and in an intermediate temperature range. These observations establish the opening of a strongly downward renormalized spin gap in the underdoped regime of LSCO. This behavior contrasts with the observed doping dependence of most electronic energy features.