Eight silicate glasses were prepared by directly fusing and stirring 50‐100 g each of basalt, andesite, komatiite, peridotite, rhyolite, and quartz‐diorite. These are referred to as MPI‐DING glasses and were made for the purpose of providing reference materials for geochemical, in‐situ microanalytical work. Results from various analytical techniques indicate that individual glass fragments are well homogenised with respect to major and trace elements at the μm to mm scale. Heterogeneities due to quench crystallisation of olivine have been observed in small and limited areas of the two komatiitic glasses. In order to obtain concentration values for as many elements as possible, the glasses were analysed by a variety of bulk and microanalytical methods in a number of laboratories. The analytical uncertainties of most elements are estimated to be between 1% and 10%. From the analytical data, preliminary reference values for more than sixty elements were calculated. The analytical uncertainties of most elements are estimated to be between 1% and 10%.

A highly conserved signaling property of Nef proteins encoded by human or simian immunodeficiency virus is the binding and activation of a PAK kinase whose function is unclear. Here we show that Nef-mediated p21-activated kinase (PAK) activation involves phosphatidylinositol 3-kinase, which acts upstream of PAK and is bound and activated by Nef similar to the manner of Polyoma virus middle T antigen. The Nef-associated phosphatidylinositol-3-PAK complex phosphorylated the pro-apoptotic Bad protein without involving the protein kinase B-Akt kinase, which is generally believed to inactivate Bad by serine phosphorylation. Consequently, Nef, but not a Nef mutant incapable of activating PAK, blocked apoptosis in T cells induced by serum starvation or HIV replication. Nef anti-apoptotic effects are likely a crucial mechanism for viral replication in the host and thus in AIDS pathogenesis.

TNF receptor superfamily member 25 (TNFRSF25; also known as DR3, and referred to herein as TNFR25) is constitutively and highly expressed by CD4 + FoxP3 + Tregs. However, its function on these cells has not been determined. Here we used a TNFR25-specific agonistic monoclonal antibody, 4C12, to study the effects of TNFR25 signaling on Tregs in vivo in mice. Signaling through TNFR25 induced rapid and selective expansion of preexisting Tregs in vivo such that they became 30%-35% of all CD4 + T cells in the peripheral blood within 4 days. TNFR25-induced Treg proliferation was dependent upon TCR engagement with MHC class II, IL-2 receptor, and Akt signaling, but not upon costimulation by CD80 or CD86; it was unaffected by rapamycin. TNFR25-expanded Tregs remained highly suppressive ex vivo, and Tregs expanded by TNFR25 in vivo were protective against allergic lung inflammation, a mouse model for asthma, by reversing the ratio of effector T cells to Tregs in the lung, suppressing IL-13 and Th2 cytokine production, and blocking eosinophil exudation into bronchoalveolar fluid. Our studies define what we believe to be a novel mechanism for Treg control and important functions for TNFR25 in regulating autoaggression that balance its known role in enhancing autoimmunity.

During HIV/SIV infection, there is widespread programmed cell death in infected and, perhaps more importantly, uninfected cells. Much of this apoptosis is mediated by Fas–Fas ligand (FasL) interactions. Previously we demonstrated in macaques that induction of FasL expression and apoptotic cell death of both CD4+ and CD8+ T cells by SIV is dependent on a functional nef gene. However, the molecular mechanism whereby HIV-1 induces the expression of FasL remained poorly understood. Here we report a direct association of HIV-1 Nef with the ζ chain of the T cell receptor (TCR) complex and the requirement of both proteins for HIV-mediated upregulation of FasL. Expression of FasL through Nef depended upon the integrity of the immunoreceptor tyrosine-based activation motifs (ITAMs) of the TCR ζ chain. Conformation for the importance of ζ for Nef-mediated signaling in T cells came from an independent finding. A single ITAM motif of ζ but not CD3ε was both required and sufficient to promote activation and binding of the Nef-associated kinase (NAK/p62). Our data imply that Nef can form a signaling complex with the TCR, which bypasses the requirement of antigen to initiate T cell activation and subsequently upregulation of FasL expression. Thus, our study may provide critical insights into the molecular mechanism whereby the HIV-1 accessory protein Nef contributes to the pathogenesis of HIV.

Regulatory T cells (Tregs) are critical for self-tolerance. While adoptive transfer of expanded Tregs limits graft-versus-host disease (GVHD) after hematopoietic cell transplantation (HCT), ex vivo generation of large numbers of functional Tregs remains difficult. Here, we demonstrate that in vivo targeting of the TNF superfamily receptor TNFRSF25 using the TL1A-Ig fusion protein, along with IL-2, resulted in transient but massive Treg expansion in donor mice, which peaked within days and was nontoxic. Tregs increased in multiple compartments, including blood, lymph nodes, spleen and colon (a GVHD target tissue). Tregs did not expand in bone marrow, a critical site for graft-versus-malignancy (GVM) responses. Adoptive transfer of in vivo expanded Tregs in the setting of MHC-mismatched or MHC-matched allo-HSCT significantly ameliorated GVHD. Critically, transplant of Treg expanded donor cells facilitated transplant tolerance without GVHD, with complete sparing of GVM. This approach may prove valuable as a therapeutic strategy promoting transplantation tolerance.

Although dispensable in vitro, HIV Nef enables high-level viral replication in infected hosts by an as yet unexplained mechanism. Previously, we proposed that Nef functionally cooperates with the viral transactivator Tat by derepressing the viral promoter via a Nef-associated kinase complex (NAKC). Here, we demonstrate that hnRNP-K, a host factor thought to facilitate crosstalk between kinases and gene expression, interacts with Nef and, as part of NAKC, nucleates Nef-interacting kinases, including Lck, PKCdelta, and PI-3 kinase, leading to Lck and Erk1/2 activation. This strongly increased HIV transcription, which depended on Tat and the NF-kB motif in the viral promoter, but not on NF-kB activation. Depletion of hnRNP-K in a Jurkat model of HIV latency increased Erk1/2 activity and greatly augmented HIV reactivating stimuli. We conclude that hnRNP-K coordinates membrane signaling with transcriptional derepression through Erk1/2 and is targeted by HIV to enable Tat-mediated transcription.

DNA sequences and three distinct in vitro functions of Nef were evaluated in a group of seven perinatally infected children. nef gene sequences obtained before and after virus culture showed that one of the five non-/slow progressors harbored a virus with large deletions. nef genes from the remaining four children were full length but contained discrete changes at a higher frequency than the rapid progressors. In functional studies, 40 of 44 Nef proteins derived from the whole study group were capable of binding the cellular serine kinase p62, indicating that this function is well conserved among naturally occurring viruses. In contrast, representative Nef proteins derived from the long-term non-/slow progressors were found to be defective or far less capable of enhancing viral replication and/or viral infectivity in herpesvirus saimiri-transformed human T cells and peripheral blood mononuclear cells. On reversion of highly prevalent point mutations in the defective proteins, viral replication could be restored to wild-type levels. Our results suggest that nef genes derived from pediatric long-term nonprogressors have gross deletions in isolated cases but a higher prevalence of discrete changes that may impair Nef function in primary T cell assays, but not all functions reported for Nef.

TNFRSF25 agonists expand Tregs in vivo and delay allograft rejection.