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31.
When cells are infected with viruses, they may trigger their apoptosis programs. In unicellular organisms, this may have protected cell populations by limiting viral replication from infected cells. Multicellular organisms can also trigger the apoptosis program after viral infection. In response, viruses have evolved a wide variety of inhibitors of apoptosis. In higher organisms, the outcome of viral infections is largely determined by the immune system. Since apoptosis is intimately linked to the function and regulation of the immune system, the ability of viruses to inhibit apoptosis could profoundly alter the immune response. Viral antiapoptotic proteins could protect infected cells from apoptosis induced by cytotoxic lymphocytes, alter antigen cross-presentation and the priming of the immune response, or modulate the expression of danger signals from sites of infection. The virus/host interaction is likely to provide useful lessons regarding the workings of the mammalian immune system. 相似文献
32.
Martine Pernollet Christian Villiers Franoise Gabert Christian Drouet Maurice Colomb 《Molecular immunology》1993,30(18):1639-1646
At inflammatory sites, before their processing, antigens are exposed to oxygen free radicals released by activated cells. The effect of hydroxyl radicals (OH·) on the structure of a protein antigen, tetanus toxin (TT) was investigated, as well as the consequences on processing and presentation. A chemical system composed of Fe-EDTA, ascorbate and H2O2 was used to produce physiological amounts of OH• radicals. TT exposed to OH· radicals presented a marked decrease of its intrinsic fluorescence with a concomitant increase of the content of bityrosine, but no fragmentation of the protein was detected by SDS-PAGE. Processing of the modified TT was analysed, by incubating TT at acidic pH with fractions enriched in plasma membranes and lysosomes obtained from a lymphoblastoid cell line (LCL). Proteolysis of OH·-treated TT was less important than proteolysis of native TT, especially upon prolonged incubations. Oxidized TT presented by LCL cells induced a greater proliferation of three different TT specific T cell clones, compared to native TT. When proteolytic digests of TT were presented by fixed LCL cells to a homologous T cell line, the proliferative response obtained in the presence of digests of OH·-treated TT was sustained, even in the case of prolonged proteolysis, whereas the response to digests of native TT fell rapidly. The relative resistance of OH·-treated TT to proteolysis appears thus responsible for its greater presentation to specific T cells, probably by protecting epitopes. 相似文献
33.
Vidal N Koyalta D Richard V Lechiche C Ndinaromtan T Djimasngar A Delaporte E Peeters M 《Journal of acquired immune deficiency syndromes (1999)》2003,33(2):239-246
The genetic diversity of HIV-1 strains in Chad was documented with a total of 107 samples from patients attending the general hospital in N'Djamena, the capital city of Chad. The genetic subtypes were identified in the V3-V5 env and p24 gag regions by sequence and phylogenetic tree analyses. Of the 107 strains, 78 had the same subtype/CRF designation between env and gag. Four subtypes and three CRFs were found to cocirculate: subtype A, 20.5%; subtype D, 18.7%; CRF02_AG, 13.1%; CRF11_cpx, 13.1%; subtype G, 3.7%; CRF01_AE, 2.8%; and subtype F1, 0.9%. The remaining 29 strains (27%) had discordant subtypes or CRF designations between env and gag; in 15 of these 29 strains, a CRF was involved in the recombination event, and 10 were subtype G in gag and subtype A in env, forming a separate subcluster within subtypes G and A. Subtype D strains represent almost 20% of the HIV-1 strains circulating in Chad and form a separate subcluster in gag and env. Nearly full-length genome sequencing for two such strains (99TCD-MN011 and 99TCD-MN012) revealed that they represent nonrecombinant subtype D variants. Compared with neighboring countries, the genetic subtype distribution of HIV-1 strains in Chad is unique for several reasons: lower prevalence of CRF02, high prevalence of CRF11 and subtype D, and absence of CRF06. These data clearly show that subtype distribution is very heterogeneous in Africa, probably the result of different founder effects. 相似文献
34.
35.
Stéphanie Chasseigneaux Stéphane Haïk Isabelle Laffont-Proust Olivier De Marco Martine Lenne Jean-Philippe Brandel Jean-Jacques Hauw Jean-Louis Laplanche Katell Peoc’h 《Neuroscience letters》2006
A valine to isoleucine mutation at residue 180 was identified in a French patient with Creutzfeldt-Jakob disease (CJD). The mutation is located in the close vicinity of one of the two N-glycosylation sites of the cellular prion protein (PrPC). Western blot analysis revealed accumulation in the brain of the pathogenic proteinase K-resistant PrP (PrPSc) isoform with the notable absence of the diglycosylated band. The mutant protein expressed in CHO cells was correctly glycosylated, suggesting that the atypical glycosylation pattern of PrPSc was not due to the mutation at position 180. These results suggest that the diglycosylated form of the mutant PrP180I prevents its conversion into the pathogenic mutant form PrPSc180I, supporting a central role of N-linked glycan chains in the PrP conversion process. 相似文献
36.
Expression and folding of an antibody fragment selected in vivo for high expression levels in Escherichia coli cytoplasm 总被引:1,自引:0,他引:1
Laden JC Philibert P Torreilles F Pugnière M Martineau P 《Research in microbiology》2002,153(7):469-474
In this review, we summarize some of our results on folding and directed evolution of an antibody fragment in Escherichia coli cytoplasm. We will also discuss some attempts to construct other antibodies active in this cellular compartment. 相似文献
37.
Nicole Fellmann Mario Bedu Gil Boudet Martine Mage Marcel Sagnol Jean-Marc Pequignot Bruno Claustrat Jocelyne Brun Liliane Peyrin Jean Coudert 《European journal of applied physiology》1992,64(3):258-265
Summary The aim of the study was to investigate the inter-relationships between pituitary-adrenal hormones and catecholamines during a prolonged competition over 6 days. Plasma adrenocorticotropic hormone (ACTH), cortisol (C), -endorphin (EP), free and sulphated adrenaline (A) and noradrenaline (NA) were measured in 11 volunteer male subjects during a national Nordic-ski race (323 km). Blood samples were obtained before the competition in the evening as control (D0), and before and after each day's racing (D1–D6). The mean daily heart rate (f
c) was calculated fromf
c values recorded every minute during the race. The results showed the following: changes in meanf
c [from 147 (SEM 3) to 156 (SEM 3) beats · min–1 according to the day] were not significant during the race. Diurnal variations in ACTH, EP and C were no longer apparent after the race: evening levels were higher than their respective D0 values during the race, except on D3 when there was a lack of response to exercise in the three hormones. Unlike ACTH and EP, pre- and postexercise C values on D1 and D2 were higher than those on the subsequent days (P<0.001). In contrast, there was a progressive accumulation of A and NA in pre-and postrace concentrations which reached a plateau in about 4 days. Positive correlations between exercise responses in ACTH, C and EP were found especially on D3 and D6 (P<0.001) but there were no significant correlations between catecholamines and the other three hormones. Thus, prolonged competition over 6 days evoked different control mechanisms for hormones of the pituitary-adrenal axis and catecholamines. A sustained catecholamine release and sympathetic activation induced a progressive NA and A accumulation during the race. In contrast, the lack of a response to exercise in ACTH, EP and C on D3 suggested a dissociated central command for pituitary axis hormones and sympathetic adrenal activation. On the following days, the response to a lack of exercise, in spite of ACTH stimulation, may have reflected an adaptation of adrenal glands to prolonged stress. 相似文献
38.
Petrella T Bagot M Willemze R Beylot-Barry M Vergier B Delaunay M Meijer CJ Courville P Joly P Grange F De Muret A Machet L Dompmartin A Bosq J Durlach A Bernard P Dalac S Dechelotte P D'Incan M Wechsler J Teitell MA 《American journal of clinical pathology》2005,123(5):662-675
Blastic natural killer (NK) cell lymphoma (also termed CD4+CD56+ hematodermic neoplasm) is a recently described entity, with the first case reported in 1994. It was suggested initially that the disease originates from NK cells. Since 1994, single cases and a few small series have been published. In this review, data from the literature and a series of 30 cases from the French and Dutch study groups on cutaneous lymphomas are discussed. The major clinical, histopathologic, and phenotypic aspects of the disease and diagnostic criteria and data suggesting a plasmacytoid dendritic cell origin for the tumor cells are provided. 相似文献
39.
Claudie Merlet-Bénichou Esther Azoulay Martine Muffat-Joly 《Pflügers Archiv : European journal of physiology》1975,354(2):187-195
Oxygen half-saturation of blood (P50), 2,3-diphosphoglycerate concentration (2,3-DPG) and Bohr effect were determined in male, and nonpregnant and pregnant female guinea pigs, according to a randomized block design. P50 was significantly higher in the female group (26.3 Torr plus or minus 0.22 SEM) than in the male group (24.8 Torr plus or minus 0.26 SEM) and was significantly lower in both these groups than in the pregnant group (27 Torr plus or minus 0.35 SEM). This difference in oxygen affinity was explained by differences in 2,3-DPG: 1.08 plus or minus 0.02 SEM in males, 1.24 plus or minus 0.03 in non-pregnant females and 1.34 plus or minus 0.03 mol/mol HB in pregnant females P50, 2,3-DPG and haemoglobin concentrations were significantly correlated for the ensemble of the 3 groups. There was no significant difference in Bohr effect between the 3 groups. 相似文献
40.
Wuyts W Roland D Lüdecke HJ Wauters J Foulon M Van Hul W Van Maldergem L 《American journal of medical genetics》2002,113(4):326-332
Multiple exostoses represent a genetically heterogeneous disorder that may occur isolated or as part of a complex contiguous gene syndrome such as Langer-Giedion syndrome on chromosome 8 and the proximal 11p deletion syndrome on chromosome 11. Here we describe a boy with multiple exostoses, hypertrichosis, mental retardation, and epilepsy due to a de novo deletion on chromosome 8q24. Molecular analysis revealed that the deletion interval overlaps with the Langer-Giedion syndrome and involves the EXT1 gene and additional genes located distal to EXT1, but probably not encompassing the TRPS1 gene located proximal to EXT1. 相似文献