Role of immune complexes in pathogenesis of renal disease

When judged by histological criteria, kidney tissue is practically devoid of immune tissue; as yet a broad spectrum of immunological diseases are targeted at the kidneys, especially at the glomeruli. Glomerular epithelial cells exhibit immune protein receptors and hence could clear immune complexes decorated with complement from the circulation. Alternatively, circulating immune complexes could become trapped in the glomerular filter and start off inflammatory reactions. Anti-glomerular basement membrane antibody reacts with glomeruli and causes glomerulonephritis. The present text is an analysis of the impact of immune complex formation on renal pathology and contains retrospective clinical data of our own hospital obtained on 192 patients undergoing diagnostic renal biopsy.     

Adsorption of fibronectin onto polymethylmethacrylate and promotion of Staphylococcus aureus adherence

Recent data suggest that fibronectin may favor Staphylococcus aureus infection by promoting attachment to either injured tissues or implanted foreign bodies. We studied the quantitative adsorption of fibronectin onto polymethylmethacrylate (PMMA) cover slips by using a 125I-labeled preparation of the purified plasma glycoprotein. Fibronectin in buffer solutions showed a high affinity to PMMA coverslips. Adherence of S. aureus Wood 46 was studied on PMMA pre-exposed to fibronectin, using an assay specifically adapted to the cover slip model. Whereas S. aureus adherence in an albumin-containing buffer was less than or equal to 10(3) CFU on control uncoated cover slips, adherence in the same medium increased up to maximum of 7.7 X 10(4) CFU on cover slips preincubated in a solution of fibronectin (125-micrograms/ml). At intermediate fibronectin concentrations, bacterial adherence was a linear function of both the quantity in solution and of the quantity adsorbed on the PMMA cover slips. The presence of human serum proteins, as represented by a fibronectin-depleted pool, essentially prevented adsorption of radiolabeled fibronectin on PMMA and subsequent bacterial adherence on the cover slips. Precoating of PMMA with denatured collagen resulted in increased fibronectin adsorption on PMMA, even in the presence of serum proteins, and S. aureus adherence was optimal on such surfaces. Collagen may therefore play a role as a cofactor contributing to S. aureus adherence onto fibronectin-coated substrata or foreign bodies.     

真核表达人呼吸道合胞病毒F蛋白的纯化方法

目的 真核表达人呼吸道合胞病毒(human respiratory syncytial virus,SV)融合蛋白(fusion protein,),并完成蛋白纯化及纯度测定.方法 根据编码F蛋白的基因序列设计引物,CR方法扩增出3'端带His标签的F基因序列,克隆入pGEM-T-easy载体,经核酸序列分析后,进一步克隆到pcDNA3.1( )真核表达载体,限制性内切酶鉴定,用脂质体Lipofectamine2000转染COS-7细胞,2 h后再用Westem blot检测目的蛋白的表达.Ni柱亲和层析纯化COS-7细胞表达的F蛋白,高效毛细管电泳分析纯化后蛋白纯度.结果 核酸序列分析证实获得带His标签的RSV F基因序列,没有发生无义突变.转染COS-7细胞后,利用Western blot方法检测到F蛋白的特异性条带,纯度达99%以上.结论 初步建立了真核表达RSV F蛋白的纯化方法,为进一步优化RSV F蛋白制备条件及单克隆抗体及诊断试剂等研究奠定了基础.     

Naturally occurring ABO antibodies: long-term stable, individually distinct anti-A IgG spectrotypes.

Spectrotypes of naturally occurring IgG antibodies to histo-blood group substance A were analyzed by isoelectric focusing and a newly developed, non-radioactive affinity immunoblotting assay. Specificity was tested by preabsorption of sera on red blood cells and on four different types of blood group substance A. Clonotype-banding patterns of sera from 18 different blood donors were individually distinct, most of them showing an oligoclonal pattern with less than 15 visible bands. To analyze the influence of IgG subclass composition on spectrotype patterns, IgG subclasses were measured by ABO enzyme-linked immunosorbent assay (ELISA) and were shown to be mostly IgG1 and IgG2. Anti-A IgG1 spectrotypes could be detected with four sera and were also individually distinct. A series of six and seven serum samples, respectively from two donors was used to analyze the time-related changes of anti-A IgG spectrotypes. Banding pattern of both individuals remained stable during the whole observation period of 167 and 82 days, respectively, and no differences between follow-up samples could be detected. This long-term stability of individual anti-A IgG spectrotypes is backed by constant serum levels of anti-A IgG and -IgM antibodies during the observation period as measured by ABO ELISA.     

Nosocomial and community acquired uropathogenic isolates of Proteus mirabilis and antimicrobial susceptibility profiles at a university hospital in Sub–Saharan Africa

ObjectiveTo ascertain antimicrobial susceptibility profile of Proteus mirabilis (P. mirabilis) from clinical urine specimens at a university hospital in the spate of its recorded increasing resistance patterns.MethodsThe study was retrospective in nature. Data generated from urine cultures of patients at University of Calabar Teaching Hospital for a period of five years (2004–2009) were compiled. Relevant information obtained were age and gender of patients, organisms recovered and their antibiotic susceptibility patterns. P. mirabilis was identified using standard laboratory procedures.ResultsP. mirabilis showed the highest resistance against ampicillin, cloxacillin, amoxicillin, tetracycline, co-trimoxazole, erythromycin and chloramphenicol (100%–37.2%) while colistin, ofloxacin, ciprofloxacin, ceftriaxone, nalidixic acid and nitrofurantoin recorded the highest activity (59.1%–96.9%) with no drug recording 100% activity. The resistance of the nosocomial isolates of the organism were significantly higher than the community acquired isolates against that of the common antibiotics in use (P<0.05).ConclusionsExtreme caution should be exercised in antibiotic administration in hospital setting and the potential benefits adequately assessed while control of nosocomial infections be given a priority so as to limit the spread of resistant bacteria.     

Recurrent meningitis in a patient with congenital deficiency of the C9 component of complement. First case of C9 deficiency in Europe

We describe the first cases, to our knowledge, of C9 deficiency in Europe that were detected in a Swiss family, of which two members--one with a complete deficiency and the other with approximately half-normal C9 levels--experienced bacterial meningitis. The index patient, a 56-year-old white man with a history of purulent meningitis at the age of 23 years, presented with an acute meningococcal meningitis. No impairment of cellular immunity or immunoglobulin deficiency could be found. Complement assays showed a complete deficiency of the C9 component, while the other individual component levels were normal and the hemolytic activity (measured using the CH50 assay) was only slightly reduced. A family study revealed complete C9 deficiency in the patient's healthy brother and half-normal C9 concentrations in his sister, his son (who also had experienced an episode of bacterial meningitis), and his niece, consistent with an inherited C9 deficiency. This first case of recurrent meningitis in a white patient with complete C9 deficiency suggests that this complement defect may also be a risk factor for bacterial, especially neisserial, infections.