Gliomas consist of multiple cell types, including an abundant number of microglia and macrophages, whereby their impact on tumor progression is controversially discussed. To understand their unique functions and consequently manipulate either microglia or macrophages in therapeutic approaches, it is essential to discriminate between both cell populations. Because of the lack of specific markers, generally total body irradiated chimeras with labeled bone marrow cells were used to identify infiltrated cells within the brain. However, total body irradiation (TBI) affects the blood-brain barrier integrity, which in turn potentially facilitates immune cell infiltration. In this study, changes on the blood-brain barrier were avoided using headprotected irradiation (HPI). Head protection and total body irradiated chimeras exhibited similar reconstitution levels of the myeloid cell lineage in the blood, enabling the comparable analyses of brain infiltrates. We demonstrate that the HPI model impeded a massive unspecific influx of donor-derived myeloid cells into naive as well as tumor-bearing brains. Moreover, experimental artifacts such as an enlarged distribution of infiltrated cells and fourfold increased tumor volumes are prevented in head-protected chimeras. In addition, our data evidenced for the first time that microglia are able to up-regulate CD45 and represent an inherent part of the CD45 high population in the tumor context. All in all, HPI allowed for the unequivocal distinction between microglia and macrophages without alterations of tumor biology and consequently permits a detailed and realistic description of the myeloid cell composition in gliomas.

Pneumonia is the leading cause of death after acute spinal cord injury and is associated with poor neurological outcome. In contrast to the current understanding, attributing enhanced infection susceptibility solely to the patient's environment and motor dysfunction, we investigate whether a secondary functional neurogenic immune deficiency (spinal cord injury-induced immune deficiency syndrome, SCI-IDS) may account for the enhanced infection susceptibility. We applied a clinically relevant model of experimental induced pneumonia to investigate whether the systemic SCI-IDS is functional sufficient to cause pneumonia dependent on spinal cord injury lesion level and investigated whether findings are mirrored in a large prospective cohort study after human spinal cord injury. In a mouse model of inducible pneumonia, high thoracic lesions that interrupt sympathetic innervation to major immune organs, but not low thoracic lesions, significantly increased bacterial load in lungs. The ability to clear the bacterial load from the lung remained preserved in sham animals. Propagated immune susceptibility depended on injury of central pre-ganglionic but not peripheral postganglionic sympathetic innervation to the spleen. Thoracic spinal cord injury level was confirmed as an independent increased risk factor of pneumonia in patients after motor complete spinal cord injury (odds ratio = 1.35, P < 0.001) independently from mechanical ventilation and preserved sensory function by multiple regression analysis. We present evidence that spinal cord injury directly causes increased risk for bacterial infection in mice as well as in patients. Besides obvious motor and sensory paralysis, spinal cord injury also induces a functional SCI-IDS ('immune paralysis'), sufficient to propagate clinically relevant infection in an injury level dependent manner.

Background-Bartonella species are the only known bacterial pathogens causing vasculoproliferative disorders in humans (bacillary angiomatosis [BA]). Cellular and bacterial pathogenetic mechanisms underlying the induction of BA are largely unknown. Methods and Results-Activation of hypoxia-inducible factor-1 (HIF-1), the key transcription factor involved in angiogenesis, was detected in Bartonella henselae-infected host cells in vitro by immunofluorescence, Western blotting, electrophoretic mobility shift, and reporter gene assays and by immunohistochemistry in BA tissue lesions in vivo. Gene microarray analysis revealed that a B henselae infection resulted in the activation of genes typical for the cellular response to hypoxia. HIF-1 was essential for B henselae-induced expression of vascular endothelial growth factor as shown by inhibition with the use of HIF-1-specific short-interfering RNA. Moreover, infection with B henselae resulted in increased oxygen consumption, cellular hypoxia, and decreased ATP levels in host cells. Infection with a pilus-negative variant of B henselae did not lead to cellular hypoxia or activation of HIF-1 or vascular endothelial growth factor secretion, suggesting a crucial role of this bacterial surface protein in the angiogenic reprogramming of the host cells. Key Words: angiomatosis, bacillary Ⅲ Bartonella henselae Ⅲ angiogenesis Ⅲ HIF-1 protein Ⅲ hypoxia A ngiogenesis is a multistep process resulting in the formation of new blood vessels from preexisting vasculature. Newly formed vessels supply oxygen and nutrients to growing tumors and are necessary for tumor progression and metastasis. 1 Angiogenesis is also a component of various cardiovascular and inflammatory diseases. 2 Hypoxiainducible factor-1 (HIF-1) is a key transcription factor for the induction of angiogenic growth factors that adjust the vascular oxygen supply to tissue metabolic demands. 3,4 Of the many genes induced by HIF-1, vascular endothelial growth factor (VEGF) plays a critical role in triggering angiogenesis as the major hypoxia-inducible mitogen for endothelial cells. 5 Interestingly, human herpesvirus-8 (HHV-8) and several Bartonella species induce angiogenesis in humans. causes the vasculoproliferative disorder Kaposi's sarcoma, 6 which has a high frequency among immunocompromised patients, such as those infected with HIV. HHV-8 -infected cells express VEGF on HIF-1 activation, 7 and this mechanism was implicated in endothelial cell proliferation in the lesions. 8 Bartonella henselae and B quintana are the etiologic agents of bacillary angiomatosis (BA) and bacillary peliosis (BP), which are histologically characterized as lobulated proliferation of mainly capillary-sized vessels and predominantly affect HIV patients. 9 These slow-growing bacteria are facultative intracellular pathogens that, like HHV-8, also induce VEGF in host cells in vitro and in BA or BP lesions of patients. 10 Endothelial cells are one presumed habitat of Bartonella. 11 Dissecting the angioproliferative strategies used Received...

Ceftriaxone causes a significant reduction in acute stroke mortality in a poststroke treatment regimen in animal studies. Improved neurological performance and survival may be due to neuroprotection by activation of GLT1 and a stimulation of neurotrophins resulting in an increased number of surviving neurons in the penumbra.

No abstract

The tetraspanin CD37 is widely expressed in B-cell malignancies and represents an attractive target for immunotherapy with mAbs. We have chimerized a high-affinity mouse Ab to CD37 and engineered the CH2 domain for improved binding to human

Adenoviruses (Ads) are icosahedral, nonenveloped viruses with a double-stranded DNA genome. The 51 known Ad serotypes exhibit profound variations in cell tropism and disease types. The number of observed Ad infections is steadily increasing, sometimes leading to fatal outcomes even in healthy individuals. Species B Ads can cause kidney infections, hemorrhagic cystitis, and severe respiratory infections, and most of them use the membrane cofactor protein CD46 as a cellular receptor. The crystal structure of the human Ad type 11 (Ad11) knob complexed with CD46 is known; however, the determinants of CD46 binding in related species B Ads remain unclear. We report here a structural and functional analysis of the Ad11 knob, as well as the Ad7 and Ad14 knobs, which are closely related in sequence to the Ad11 knob but have altered CD46-binding properties. The comparison of the structures of the three knobs, which we determined at very high resolution, provides a platform for understanding these differences and allows us to propose a mechanism for productive high-affinity engagement of CD46. At the center of this mechanism is an Ad knob arginine that needs to switch its orientation in order to engage CD46 with high affinity. Quantum chemical calculations showed that the CD46-binding affinity of Ad11 is significantly higher than that of Ad7. Thus, while Ad7 and Ad14 also bind CD46, the affinity and kinetics of these interactions suggest that these Ads are unlikely to use CD46 productively. The proposed mechanism is likely to determine the receptor usage of all CD46-binding Ads.The nonenveloped adenoviruses (Ads) typically cause respiratory infections, with symptoms ranging from the common cold to pneumonia, but they can also infect the eye, urinary tract, and intestine. Individuals with compromised immune systems are especially prone to severe and life-threatening infections caused by Ads (24). The virion measures about 800 Å in diameter and carries a double-stranded DNA genome. Its icosahedral capsid is primarily formed by 240 copies of the hexon and 12 copies of the penton proteins (3). A trimeric, elongated protein called "fiber" protrudes from each of the 12 vertices of the capsid and mediates the initial attachment to target cells by interacting with cell surface receptors. The fiber consists of a globular head, a fibrous shaft, and a tail. The knob mediates interactions with receptors, whereas the tail anchors the fiber to the penton base. The engagement of receptors is followed by viral internalization via clathrin-coated endocytosis (54).A group of highly pathogenic species B Ads use the membrane cofactor protein CD46 as their cellular receptor (18,20,25,44,50). The heavily glycosylated extracellular portion of CD46 is composed of four short consensus repeat (SCR) modules and a 25-amino-acid sequence rich in serine, threonine, and proline residues (the STP region). CD46 inhibits complement activation by binding separately to C3b or C4b and stabilizes them for proteolytic cleavage by factor I, thus preventing conti...

Sulphur (S) is an essential element for all living organisms. The uptake, assimilation and metabolism of S in plants are well studied. However, the regulation of S homeostasis remains largely unknown. Here, we report on the identification and characterisation of the more sulphur accumulation1 (msa1-1) mutant. The MSA1 protein is localized to the nucleus and is required for both S-adenosylmethionine (SAM) production and DNA methylation. Loss of function of the nuclear localised MSA1 leads to a reduction in SAM in roots and a strong S-deficiency response even at ample S supply, causing an over-accumulation of sulphate, sulphite, cysteine and glutathione. Supplementation with SAM suppresses this high S phenotype. Furthermore, mutation of MSA1 affects genome-wide DNA methylation, including the methylation of S-deficiency responsive genes. Elevated S accumulation in msa1-1 requires the increased expression of the sulphate transporter genes SULTR1;1 and SULTR1;2 which are also differentially methylated in msa1-1. Our results suggest a novel function for MSA1 in the nucleus in regulating SAM biosynthesis and maintaining S homeostasis epigenetically via DNA methylation.