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91.
Geographical and temporal conservation of antibody recognition of Plasmodium falciparum variant surface antigens 下载免费PDF全文
Nielsen MA Vestergaard LS Lusingu J Kurtzhals JA Giha HA Grevstad B Goka BQ Lemnge MM Jensen JB Akanmori BD Theander TG Staalsoe T Hviid L 《Infection and immunity》2004,72(6):3531-3535
The slow acquisition of protection against Plasmodium falciparum malaria probably reflects the extensive diversity of important antigens. The variant surface antigens (VSA) that mediate parasite adhesion to a range of host molecules are regarded as important targets of acquired protective immunity, but their diversity makes them questionable vaccine candidates. We determined levels of VSA-specific immunoglobulin G (IgG) in human plasma collected at four geographically distant and epidemiologically distinct localities with specificity for VSA expressed by P. falciparum isolates from three African countries. Plasma levels of VSA-specific IgG recognizing individual parasite isolates depended on the transmission intensity at the site of plasma collection but were largely independent of the geographical origin of the parasites. The total repertoire of immunologically distinct VSA thus appears to be finite and geographically conserved, most likely due to functional constraints. Furthermore, plasma samples frequently had high IgG reactivity to VSA expressed by parasites isolated more than 10 years later, showing that the repertoire is also temporally stable. Parasites from patients with severe malaria expressed VSA (VSASM) that were better recognized by plasma IgG than VSA expressed by other parasites, but importantly, VSASM-type antigens also appeared to show substantial antigenic homogeneity. Our finding that the repertoire of immunologically distinct VSA in general, and in particular that of VSASM, is geographically and temporally conserved raises hopes for the feasibility of developing VSA-based vaccines specifically designed to accelerate naturally acquired immunity, thereby enhancing protection against severe and life-threatening P. falciparum malaria. 相似文献
92.
Inflammatory recruitment of leukocytes into the cerebrospinal fluid (CSF) during bacterial meningitis has been shown to contribute to the neurological damage commonly associated with this disease. In this study we tested whether inhibition of firm leukocyte adhesion to vascular endothelium could reduce leukocyte recruitment into the subarachnoid space (SAS) and into the skin in rabbits challenged with pneumococcal cell wall (PCW) antigen. PCW was given either as an intracisternal or an intradermal (i.d.) injection. Intravenous (i.v.) treatment with a monoclonal antibody (mAb), IB4, against the leukocytic adhesion molecule CD18 has previously been documented to attenuate leukocyte CSF accumulation in experimental bacterial meningitis. In the present study, i.v. treatment with anti-CD18 mAbs (IB4) only tended to inhibit CSF leukocyte influx in animals with PCW-induced meningitis. However, if the antigen was injected i.d., treatment i.v. with the same mAb (IB4) dramatically reduced leukocyte accumulation in the skin. Our findings indicate that the mechanisms responsible for PCW-induced inflammatory accumulation of leukocytes in skin and meninges are different. 相似文献
93.
Sala F Mulet J Reddy KP Bernal JA Wikman P Valor LM Peters L König GM Criado M Sala S 《Neuroscience letters》2005,373(2):144-149
The effects of various Flustra foliacea metabolites on different types of human neuronal nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes were investigated. Whereas most of the compounds tested had a small blocking effect, one of them, deformylflustrabromine, selectively increased the current obtained in alpha4beta2 receptors when co-applied with acetylcholine (ACh). The current increase was reversible and concentration-dependent. This potentiating effect was still present at saturating concentrations of acetylcholine, and no changes in single-channel conductance or reversal potential were observed, thus suggesting a modification in the gating of alpha4beta2 receptors. Dwell time analysis of single channel records indicates that the mechanism of action of deformylflustrabromine could be both an increase of the opening rate constant and a decrease of the closing rate constant on alpha4beta2 receptors. Thus, deformylflustrabromine may constitute an excellent starting point for the future development of related agents able to potentiate human neuronal nicotinic receptor function. 相似文献
94.
Rapid PCR Detection of Helicobacter pylori-Associated Virulence and Resistance Genes Directly from Gastric Biopsy Material 总被引:8,自引:0,他引:8 下载免费PDF全文
Britta Bjrkholm Ragnar Befrits Bernhard Jaup Lars Engstrand 《Journal of clinical microbiology》1998,36(12):3689-3690
We have developed a PCR-based method to detect macrolide resistance and the virulence gene cagA in Helicobacter pylori within 24 h, thereby improving the lengthy process of culture-based approaches. Total DNA was prepared directly from stomach biopsy specimens. The procedure proved to be rapid and reliable and could be utilized for diagnostic purposes. 相似文献
95.
Sj?gren Anita; Hillensj? Torbj?rn; Hamberger Lars 《Human reproduction (Oxford, England)》1987,2(6):469-473
Granulosa cells were aspirated from human pre-ovulatory folliclesfollowing a combined clomiphene-gonadotrophin stimulation inan in-vitro fertilization (IVF) programme. The cells were culturedfor 8 days in medium M199 containing 10% bovine fetal calf serumunder 5% CO2 in air. Pure human FSH and human LH were addedalone or in combination to the culture in various concentrationsand the progesterone (P) and oestradiol-17 (E2) levels in themedium were measured every second day by a conventional RIAtechnique. In the presence of FSH or LH the formation of P increased2- to 3-fold with the pronounced effect after 4 to 6 days inculture. Addition of testosterone (T) (3 ? 107 M) tothe culture medium affected neither basal nor gonadotrophinstimulated P formation. In this system, only minute amountsof E2 were formed and neither FSH nor LH stimulated its formation.When the medium was fortified with T, basal E2 formation increased50- to 100-fold. FSH further stimulated this conversion significantlyafter 6 and 8 days of culture, while LH had no significant influence. 相似文献
96.
Blacker D Bertram L Saunders AJ Moscarillo TJ Albert MS Wiener H Perry RT Collins JS Harrell LE Go RC Mahoney A Beaty T Fallin MD Avramopoulos D Chase GA Folstein MF McInnis MG Bassett SS Doheny KJ Pugh EW Tanzi RE;NIMH Genetics Initiative Alzheimer's Disease Study Group 《Human molecular genetics》2003,12(1):23-32
Alzheimer's disease (AD) is a devastating neurodegenerative disorder of late life with complex inheritance. Mutations in three known genes lead to the rare early-onset autosomal dominant form of AD, while a common polymorphism (epsilon 4) in the gene encoding apolipoprotein E (APOE ) is a risk factor for more typical late-onset (>60 years) AD. A recent study concluded that there are up to four additional genes with an equal or greater contribution to the disease. We performed a 9 cM genome screen of 437 families with AD, the full National Institute of Mental Health (NIMH) sample, which has been carefully ascertained, evaluated and followed by our group over the last decade. Performing standard parametric and non-parametric linkage analyses, we observed a 'highly significant' linkage peak by Lander and Kruglyak criteria on chromosome 19q13, which probably represents APOE. Twelve additional locations-on 1q23, 3p26, 4q32, 5p14, 6p21, 6q27, 9q22, 10q24, 11q25, 14q22, 15q26 and 21q22-met criteria for 'suggestive' linkage [i.e. two-point lod score (TLS) >/=1.9 and/or multipoint lod score (MLS) >/=2.2] in at least one of our analyses. Although some of these will surely prove to be false positives, these linkage signals should provide a valuable framework for future studies aimed at identifying additional susceptibility genes for late-onset AD. 相似文献
97.
Gunnel Bjerneroth Claes Juhlin Lars Grimelius Jonas Rastad Göran Åkerström 《Endocrine pathology》1992,3(2):83-92
The monoclonal antiparathyroid antibody E11 reacts with a glycoprotein of high molecular weight, which acts as a calcium receptor on the surface of parathyroid cells and mediates calcium regulation of parathyroid hormone (PTH) release. Reduced expression of the calcium receptor has been implicated as a cause of the defect in PTH regulation in the pathological parathyroid parenchyma of patients with hyperparathyroidism (HPT). The present study evaluated the efficacy of immunostainings with the E11 antibody in comparison with routine histopathological methods including staining by the oil red O technique for histological discrimination between normal and pathological parathyroid glands. Parathyroid tissue from euparathyroid individuals invariably presented intense and homogeneous surface staining, with the antibody on virtually all chief cells, while the pathological glands from patients with HPT consistently showed heterogeneous and reduced immunostaining. Even minimally enlarged pathological glands from individuals with mild hypercalcemia and the normal-sized glands associated with adenomas displayed parathyroid chief cells with reduced antibody reactivity. The monoclonal antiparathyroid antibody should constitute a useful tool in parathyroid histopathology not only by its ability to identify the parathyroid tissue, but also by directly demonstrating the functionally normal and abnormal cells within the parathyroid tissue. 相似文献
98.
Characterization of an IgA receptor from group B streptococci: specificity for serum IgA 总被引:8,自引:0,他引:8
Gunnar Lindahl Bo kerstrm Jean-Pierre Vaerman Lars Stenberg 《European journal of immunology》1990,20(10):2241-2247
Some strains of group B streptococci express a cell surface protein which binds IgA. This report describes some properties of such an IgA receptor and compares it with a previously described IgA receptor from group A streptococci. The group B receptor was released in an almost pure form from bacteria incubated at elevated pH, and could be isolated by IgA-Sepharose affinity chromatography. The sequence of the N-terminal 19 amino acid residues was unique. The receptor preferentially binds IgA of human origin, as shown in immunoblotting experiments with purified IgA from nine different species. The affinity constant of the purified receptor for serum IgA was determined to be 3.5 x 10(8) M-1, but for secretory IgA it was too low to allow determination. This result indicates that secretory component and/or J chain interferes with the binding of IgA to this type of bacterial receptor, which may be one of the physiological functions of these polypeptides. A reduction in affinity was also observed for another complexed form of IgA, alpha 1-microglobulin-IgA. The group B receptor is antigenically unrelated to the IgA receptor from group A streptococci (protein Arp), but competitive inhibition experiments indicate that they bind to the same region in IgA. The implications of these findings, and the biological role of bacterial IgA receptors, are discussed. 相似文献
99.
100.
Variations in attachment ofNeisseria gonorrhoeae to vaginal epithelial cells during the menstrual cycle and early pregnancy 总被引:3,自引:0,他引:3
An in vitro system was used to study the ability of virulent gonococci to adhere to vaginal epithelial cells obtained from healthy donors during the pre- and postmenstrual phases, and from those in early pregnancy. It was found that more gonococci adhered to the cells from donors in the postmenstrual phase than to cells from those in the premenstrual one. This difference was statistically highly significant. The attachment rate of gonococci to vaginal epithelial cells was similar in early pragnancy and in the premenstrual phase. 相似文献