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71.
72.
Non-melanoma skin cancer is the most frequent malignancy in Caucasian populations. Evidence suggests the involvement of cutaneous Human Papillomavirus (HPV) of the genus beta (beta) in this disease. The ability of E6 and E7 of mucosal HPV to promote cellular transformation and inhibit immune response-related pathways plays a key role in cervical carcinogenesis. beta HPV-38 E6 and E7 display transforming activities in in vitro and in vivo models, but their impact on immune surveillance is unknown. Here we show that HPV-38 E6 and E7 affect the IFN-induced up-regulation of MHC class I. Expression of the two viral proteins in HaCaT keratinocytes led to a decrease of MHC I levels. This down-regulation is associated with a reduction of expression of MHC I heavy chain, of the peptide chaperone TAP and of the STAT-1 downstream effector IRF-1. The down-regulation of these proteins is ultimately due to the inhibition of STAT-1 expression. Analysis of cells expressing either HPV-38 E6 or E7 suggests that these effects are primarily the result of E6 expression, although a contribution by E7 cannot be excluded. We conclude that HPV-38 encodes oncoproteins that potentially contribute to the evasion of host immune surveillance. 相似文献
73.
74.
Ke Zheng Jordi Xiol Michael Reuter Sigrid Eckardt N. Adrian Leu K. John McLaughlin Alexander Stark Ravi Sachidanandam Ramesh S. Pillai Peijing Jeremy Wang 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(26):11841-11846
Piwi-interacting RNAs (piRNAs) are essential for silencing of transposable elements in the germline, but their biogenesis is poorly understood. Here we demonstrate that MOV10L1, a germ cell–specific putative RNA helicase, is associated with Piwi proteins. Genetic disruption of the MOV10L1 RNA helicase domain in mice renders both MILI and MIWI2 devoid of piRNAs. Absence of a functional piRNA pathway in Mov10l1 mutant testes causes loss of DNA methylation and subsequent derepression of retrotransposons in germ cells. The Mov10l1 mutant males are sterile owing to complete meiotic arrest. This mouse mutant expresses Piwi proteins but lacks piRNAs, suggesting that MOV10L1 is required for piRNA biogenesis and/or loading to Piwi proteins. 相似文献
75.
The 175-kDa erythrocyte binding protein (EBA-175) of Plasmodium falciparum and Duffy antigen binding proteins of P. vivax and P. knowlesi are members of a protein family. The features of this protein family include a cysteine-rich motif present in the erythrocyte receptor-binding domain. We identify here a novel 140-kDa P. falciparum erythrocyte binding protein (EBP2/BAEBL) containing the signature cysteine-rich motif by comparative analysis of gene sequence information. Polyclonal antibodies generated by immunization with an EBP2/BAEBL DNA vaccine immunoprecipitated a 140-kDa protein from P. falciparum schizont-infected erythrocyte lysates. Similar to EBA-175, the binding of EBP2/BAEBL to human erythrocytes was dependent on sialic acids because neuraminidase treatment of those erythrocytes rendered them incapable of binding, but differed from EBA-175 in that trypsin treatment decreased EBP2/BAEBL binding by only twofold compared to a 10-fold reduction in EBA-175 binding. Antibodies raised against the putative erythrocyte-binding domain of EBP2/BAEBL effectively blocked the binding of native EBP2/BAEBL to erythrocytes. These functional antibodies localize EBP2/BAEBL to the invasive apical end of the merozoite. We identify EBP2/BAEBL as a paralogue of EBA-175 and as a novel P. falciparum vaccine candidate. 相似文献
76.
Taylor PR Reid DM Heinsbroek SE Brown GD Gordon S Wong SY 《European journal of immunology》2005,35(7):2163-2174
Dectin-2 is a recently described dendritic-cell-associated receptor, suggested to be involved in the initiation and maintenance of UV-induced tolerance. To understand the physiological relevance of the proposed functions of this C-type lectin-like receptor, we have generated monoclonal antibodies against its extracellular domain and performed a detailed study of its expression. In naive mice, Dectin-2 has a novel distribution pattern compared with other myeloid markers, but is predominantly expressed by a wide variety of tissue macrophages. Its expression was limited on dendritic cells and notably absent from brain microglia and choroid plexus or meningeal macrophages. On peripheral blood monocytes, Dectin-2 expression was very low on the surface but was transiently and markedly up-regulated on induction of inflammation in vivo using a variety of stimuli. This change in Dectin-2 expression occurs on 'inflammatory' monocytes after arrival at the inflammatory lesion as demonstrated by adoptive cell-transfer studies, and is independent of whether the macrophages elicited by the stimuli ultimately expressed Dectin-2. These observations show Dectin-2 expression to be characteristic of monocyte activation/maturation at an inflammatory lesion and provide a new perspective on the interpretation of Dectin-2 function in vivo. 相似文献
77.
Sigrid C. Schwarz Hansjörg Sauer Wolfgang H. Oertel Christopher D. Earl Andreas R. Kupsch 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,115(1):71-82
We employed intracerebral co-transplantation of foetal xenogeneic striatal mouse tissue and allogeneic rat substantia nigra
into the adult rat brain to elucidate the effects of xenogeneic mouse graft on the function and survival of an allogeneic
rat graft in 6-hydroxydopamine lesioned Sprague-Dawley rats. Foetal mouse striatum (STR) and rat substantia nigra (VM) were
transplanted as non-pooled separate deposits or a pooled cell suspension with or without cyclosporin A (Cy A). Immunosuppressed
recipients of pooled rat and mouse co-grafts showed a significantly better compensation of amphetamine-induced rotational
behaviour compared with non-immunosuppressed animals with pooled rat and mouse co-grafts 3 and 6 weeks post-grafting.Tyrosine
hydroxylase (TH) immunohistochemistry revealed a non-significant reduction in survival in pooled (1806.3±367.5 cells) rat
and mouse co-transplants without immunosuppression compared with immunosuppressed pooled (3383.3±732.7 cells) animals with
allo- and xenogeneic tissue and controls (3506.4±839.3 cells). Graft volumes were significantly reduced in pooled transplants
without immunosuppression (0.1±0.026 mm3; ANOVA post-hoc SchefféF-test, P<0.0001) compared with immunosuppressed recipients (0.7±0.1 mm3) and controls (0.6±0.1 mm3). In non-pooled allo- and xenogeneic grafts without immunosuppression the survival rate of the TH-immunoreactive cells and
graft volumes were reduced (2359.3±479.5 cells; 0.2±0.043 mm3) compared with immunosuppressed animals (2927.3±946.6 cells; 0.6±0.2 mm3) and controls (2701.1±693.8 cells; 0.3±0.1 mm3) without reaching a level of significance. Rejection of mouse tissue was observed in all non-immunosuppressed recipients.
In summary: (i) continued immunosuppression yielded significant beneficial effects on function and beneficial effects on survival
of pooled grafts with an immunogenetic disparity; (ii) the rejection of a xenogeneic graft component may compromise survival
and function of other, allogeneic graft components; and (iii) transplantation of non-pooled allo- and xenogeneic tissues may
result in a better survival of the graft compared with pooled cell suspensions.
Received: 25 March 1996 / Accepted: 1 December 1996 相似文献
78.
Tenover FC McAllister S Fosheim G McDougal LK Carey RB Limbago B Lonsway D Patel JB Kuehnert MJ Gorwitz R 《Journal of clinical microbiology》2008,46(9):2837-2841
This study characterizes methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates recovered from nasal cultures of noninstitutionalized individuals in the United States obtained in 2001 to 2004 as part of the National Health and Nutrition Examination Survey. Every tenth MSSA isolate and all MRSA isolates were typed by pulsed-field gel electrophoresis (PFGE), screened for multiple toxin genes, and tested for susceptibility to 14 antimicrobial agents. USA200, USA600, and USA900 were the predominant PFGE types among MSSA isolates in both the 2001 to 2002 and the 2003 to 2004 time periods, although they accounted for only 51.3% of 316 MSSA isolates typed in 2001 and 2002 and only 43.4% of 237 MSSA isolates typed in 2003 and 2004. In contrast, USA100, USA800, and USA700 accounted for 80.0% of the 75 MRSA isolates typed in 2001 and 2002, while USA100, USA800, and USA300 accounted for 78.4% of 134 MRSA isolates typed in 2003 and 2004. The proportion of MRSA isolates that were USA300 increased significantly from the first to the second time period (P = 0.03). Most USA200 isolates (both MSSA and MRSA) carried the gene for toxic shock syndrome toxin; however, carriage of the genes encoding Panton-Valentine leukocidin, while common among MRSA of PFGE type USA300, was rare among MSSA USA300 in both time periods. Most MSSA isolates remained susceptible to all antimicrobial agents except erythromycin (79.1 and 76.0% susceptibilities in the 2001 to 2002 and the 2003 to 2004 periods, respectively). In contrast, the proportions of MRSA isolates that were susceptible to chloramphenicol, clindamycin, and erythromycin were lower in 2003 and 2004 than in 2001 and 2002, although none of these differences was statistically significant. 相似文献
79.
Clones of tomato golden mosaic virus (TGMV), a key model for geminivirus research, have been transmitted back to their original host tomato for the first time. In contrast to the high pathogenicity in other solanaceous species, TGMV induced only very mild symptoms: a few chlorotic spots on the leaf lamina for the common variant (formerly strain cs), and limited vein yellowing for the yellow vein variant (yv). Symptoms disappeared over time, though viral DNA remained detectable in newly developed leaves. Both TGMV variants invaded phloem and, occasionally, also mesophyll parenchyma cells in tomato. Complete direct sequencing of rolling circle amplification products of the viral progeny in tomato plants revealed the consensus of the DNA populations for the two genome components (DNA-A, DNA-B) of both TGMV variants. The DNA-A components showed 98.5% and 99.9% nucleotide sequence identity, respectively, with the independently cloned TGMV molecule sequenced initially in 1984, confirming the classification of csTGMV and yvTGMV as variants. The results are discussed with reference to the history of the Brazilian "mosaico dourado" disease in tomato, and the odyssey of TGMV passaging through Nicotiana benthamiana plants and bacteria of numerous laboratories worldwide. 相似文献
80.
Zakrzewicz A Krasteva G Wilhelm J Dietrich H Wilker S Padberg W Wygrecka M Grau V 《Immunobiology》2011,216(7):854-861
During acute rejection, numerous pro-inflammatory and cytotoxic monocytes accumulate in the vasculature of experimental renal allografts. Arrestins (ARRBs) are cellular regulators of inflammation, but nothing is known about their expression during rejection. Intravascular mononuclear graft leukocytes were isolated 4 days after kidney transplantation. ARRB1 and ARRB2 mRNA expression was reduced in blood leukocytes from allografts undergoing acute rejection, whereas on the protein level only ARRB2 was changed. Flow cytometry and confocal microscopy revealed ARRB1 and ARRB2 expression by monocytes and T cells, with a selective decrease in ARRB2 expression in monocytes during acute rejection. I-κB directly interacted with ARRB2 and the levels of both proteins strongly correlated. Concomitantly, the mRNA expression of NF-κB targeted genes increased. Our results suggest that activation of blood monocytes in renal isografts is dampened by high ARRB2 levels. During acute rejection, ARRB2 levels are reduced and classical monocyte activation is enabled via NF-κB activation. 相似文献