Traditional healers, traditional hospitals and HIV / AIDS: a case study in KwaZulu-Natal.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
K Munk
Publications and source records attributed to K Munk.
Carbohydrate masking of an antigenic epitope of influenza virus haemagglutinin independent of oligosaccharide size.
Comparison of the haemagglutinins (HA) of the pathogenic avian influenza viruses A/FPV/Dutch/27 (H7N7) and A/FPV/Rostock/34 (H7N1) revealed 94.7% nucleotide and 93.8% amino acid sequence homologies. Six of the seven N-glycosidic oligosaccharides of the Rostock HA are at the same positions as the six carbohydrates of the Dutch strain. The additional oligosaccharide side chain of the Rostock strain, which is of the complex type, is attached to asparagine149 in antigenic epitope B. The accessibility of this antigenic epitope has been analysed by using rabbit antisera raised against synthetic peptides comprising amino acids 143-162. The carbohydrates of the HA of the Rostock strain have been modified (i) to truncated cores by expression in insect cells using a baculovirus vector, (ii) to oligomannosidic side chains by growth in the presence of the trimming inhibitor methyldeoxynojirimycin and (iii) to a single N-acetylglucosamine residue by removal of the oligomannosidic sugar with endo-beta-N-acetylglucosaminidase H. Neither the authentic nor the modified oligosaccharides allowed antibody binding, as indicated by enzyme-linked immunosorbent assay (ELISA) and Western blot analyses. Reactivity was observed, however, after complete removal of the carbohydrate from HA of the Rostock strain by digestion with peptide-N-glycosidase F. HA of the Dutch strain was reactive without prior peptide-N-glycosidase F treatment. These results demonstrate that a single N-acetyl-glucosamine at asparagine149 is sufficient to prevent recognition of the peptide epitope.
Amino Acid Sequence↗
Structure and assembly of hemagglutinin mutants of fowl plague virus with impaired surface transport.
Five temperature-sensitive mutants of influenza virus A/FPV/Rostock/34 (H7N1), ts206, ts293, ts478, ts482, and ts651, displaying correct hemagglutinin (HA) insertion into the apical plasma membrane of MDCK cells at the permissive temperature but defective transport to the cell surface at the restrictive temperature, have been investigated. Nucleotide sequence analysis of the HA gene of the mutants and their revertants demonstrated that with each mutant a single amino acid change is responsible for the transport block. The amino acid substitutions were compared with those of mutants ts1 and ts227, which have been analyzed previously (W. Schuy, C. Will, K. Kuroda, C. Scholtissek, W. Garten, and H.-D. Klenk, EMBO J. 5:2831-2836, 1986). With the exception of ts206, the changed amino acids of all mutants and revertants accumulate in three distinct areas of the three-dimensional HA model: (i) at the tip of the 80-A (8-nm)-long alpha helix, (ii) at the connection between the globular region and stem, and (iii) in the basal domain of the stem. The concept that these areas are critical for HA assembly and hence for transport is supported by the finding that the mutants that are unable to leave the endoplasmic reticulum at the nonpermissive temperature do not correctly trimerize. Upon analysis by density gradient centrifugation, cross-linking, and digestion with trypsin and endoglucosaminidase H, two groups can be discriminated among these mutants: with ts1, ts227, and ts478, the HA forms large irreversible aggregates, whereas with ts206 and ts293, it is retained in the monomeric form in the endoplasmic reticulum. With a third group, comprising mutants ts482 and ts651 that enter the Golgi apparatus, trimerization was not impaired.
Amino Acid Sequence↗
HSV-1 gB and VZV gp-II crossreactive antibodies in human sera.
The specificity and prevalence of human IgG antibodies crossreactive between HSV-1 (ANG) and VZV (Ellen) was examined in immunoblots. Using antibody fractions purified on HSV- and VZV-coated affinity chromatography columns and by preadsorption of sera with HSV and/or VZV lysates a crossreactivity between HSV-1 gB and VZV gp-II was demonstrated. Crossreaction of human IgG antibodies among other structural and nonstructural viral proteins, however, was not detected. The frequency of human IgG antibodies crossreactive between HSV-1 gB and VZV gp-II was highest in HSV-seropositive patients experiencing an acute primary VZV infection (4 out of 5 sera tested). In contrast, no crossreactive antibodies were found in sera of HSV-seronegative patients with acute primary VZV infection (0/6) or in sera from individuals with acute recurrent HSV or VZV infection (0/12). Analysis of sera from individuals with previous HSV and/or VZV infection showed the presence of antibodies crossreactive between HSV-1 gB and VZV gp-II in 3 out of 30 sera tested.
Antibodies, Viral↗
Conserved organization of an avian histone gene cluster with inverted duplications of H3 and H4 genes.
The organization of histone gene clusters of the duck Cairina moschata was studied in the DNA inserts of two recombinant phage that overlap and feature identical histone gene arrangements but differ in sequence details and in the extent of repetition of an AT-rich motif in one of the nontranscribed spacer regions. These few but substantial differences between otherwise nearly identical histone gene groups suggest that we have independently isolated alleles of the same site of the duck genome or that this gene arrangement occurs (with slight variations) more than once per haploid genome. Within the histone gene cluster described, H3 and H4 genes are duplicated (with inverted orientation), whereas one H1 gene is flanked by single H2A and H2B genes. The arrangement of duck histone genes described here is identical to a subsection of the chicken genome but differs from any other published histone gene cluster.
Amino Acid Sequence↗
The Japanese-German cooperation in cancer research: history, presence, future.
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Forecasting↗
Homology of the HSV-2 "a-sequence" to cellular sequences.
Bgl-II fragments of the genome of Herpes simplex virus type 2 (HSV-2) HG-52 were cloned into the vector p-Neo and were used to screen the complete HSV-2 genome for regions cross-hybridizing with the genome of HEL cells. Most extensive cross-hybridizing activity was observed with a 530 bp SstII subfragment of the viral BamHI G DNA-fragment (contained in Bgl II F), which spans the joint and the viral a-sequence. From a lambda-L47 library, a cellular 15 kb HindIII DNA fragment was subcloned in pBR 322 which contained a 1920 bp SstII subfragment having strong cross-hybridizing activity with the 530 bp Sst II fragment of HSV-2 BamHI G. Within this 1920 bp Sst II fragment the cross-hybridizing activity was confined to a 230 bp Bgl I/Hpa II subfragment. This 230 bp fragment (including the flanking sequences) was analyzed in comparison to the viral a-sequence. Sequence data revealed a (G + C) content of 66% in the cellular and 81% in the viral DNA fragment, which is mainly determined by an extremely (G + C) rich 16-fold direct repeat (DR2) at the 5'-end. The homology between both DNA-fragments varies between 56% and 79% within the L-S inversion region. Both sequences, furthermore, show homology to the human c-myc protooncogene.
Animals↗
Removal of N-linked carbohydrates decreases the infectivity of herpes simplex virus type 1.
Purified preparations of herpes simplex virus type 1 Angelotti were digested with the exoglycosidases sialidase, beta-galactosidase, N-acetyl-beta-D-glucosaminidase and alpha-mannosidase, and with the endoglycosidases Endo-H and Endo-F. It was found that treatment of virions with Endo-F specifically decreased viral infectivity by a factor of 10. This reduction in titre was not associated with any measurable differences in virus adsorption, suggesting a role of N-linked complex type oligosaccharide chains in penetration. In contrast, a reduction in titre observed upon digestion of virions with exoglycosidases could be attributed to a proteolytic contamination in these enzyme preparations. Treatment of virions with Endo-H, demonstrated to be free of proteolytic contamination, did not reduce viral infectivity. Analysis of endoglycosidase-digested virions by monospecific antibodies and immunoblotting revealed a susceptibility of all four major glycoproteins (gC, gB, gE and gD) to Endo-F, but only gB was susceptible to Endo-H treatment. In contrast, of all the exoglycosidases used only sialidase was found to be active towards native viral glycoproteins. Upon analysis of endoglycosidase-digested virions we could not find any evidence for proteolysis, degradation or altered protein composition of viral envelopes. In contrast, vigorous inhibition of glycoprotein glycosylation by tunicamycin led to the formation of physically intact virions almost completely lacking all major glycoproteins. These data show that digestion of intact virions with glycosidases allows an analysis of the functional relevance of carbohydrate residues without any obvious alterations in the virion glycoprotein composition.
Adsorption↗
Analysis of the IgM and IgG antibody response against herpes simplex virus type 1 (HSV-1) structural and nonstructural proteins.
In the present study the reactivity of IgG and IgM antibodies against HSV-1 structural and nonstructural proteins was analyzed by Western blot analysis (WBA) and radioimmunoprecipitation followed by polyacrylamide gel electrophoresis (RIPA-PAGE). It was demonstrated that IgM and IgG antibodies were directed against viral immediate-early, early, and late proteins. Following acute primary HSV infection, the early IgM antibody response in general was found to be directed against nonglycosylated structural proteins, viral early and immediate-early polypeptides. IgM antibodies against viral glycoproteins were found inconsistently. IgG antibodies against viral glycoproteins and other structural proteins with an apparent molecular weight of 56 kD, 45 kD, and 39 kD could be detected early in infection. Viral early and immediate-early proteins were poorly recognized by IgG antibodies in acute primary infections. In recurrent HSV infections, IgM antibodies revealed a less complex reaction with viral polypeptides. Thus, such IgM antibodies reacted predominantly with viral nonglycosylated structural proteins. In contrast, IgG antibodies from patients with recurrent infections strongly recognized viral structural, early, and immediate-early proteins. In seropositive individuals without obvious symptoms of acute infection, the most prominent antibody response was directed against gB and gD.
Acute Disease↗
Low back strain in Danish semi-skilled construction work.
Danish semi-skilled construction workers (SC-workers) perform a variety of tasks in building construction, civil engineering and rebuilding. A previous epidemiologic study indicated a high occurrence of low back pain (LBP) among these workers. The study was designed to quantify the major occupational risk factors associated with the development of LBP, i e, inclined postures, repetitive movements, heavy lifts, pushing/pulling motions, sudden unexpected strains and whole body vibrations in this group of construction workers. Firstly a study of occupational activity of 112 SC-workers on height construction sites during two separate five-days periods was carried out. This was followed by an observational study of the nine work tasks most common to SC-workers. Heavy lifts, pushing/pulling motions and sudden unexpected strain occurred most frequently in the work, while inclined postures, repetitive movements and whole body vibrations characterised different parts of the work. Assessments of the strain were made on the basis of techniques given in the literature.
Journal Article↗
Human cytomegalovirus replicates in primary human bone marrow cells.
As an attempt to elucidate further the pathogenesis of human cytomegalovirus (HCMV) infection the replication of HCMV in primary human bone marrow cells (BMC) has been investigated. It was found that BMC held in culture in general were susceptible to HCMV infection. Compared to human embryonic lung cells, however, the replicative cycle of HCMV AD169 in BMC as determined by the analysis of viral protein and DNA synthesis was delayed and productive virus infection was restricted to a subset of BMC not exceeding 21% of the total cell population. Both of these phenomena may explain the short-term persistence of HCMV in BMC cultures which was observed over 3 months. By experiments with specifically enriched and depleted cell populations and by indirect double immunofluorescence experiments we found that both bone marrow fibroblasts and a subset of bone marrow stem cells supported productive virus infection. The finding that HCMV replicates in early stem cells of the human bone marrow may explain important aspects of the pathogenesis of HCMV infection including the presence of HCMV in peripheral blood leukocytes.
Bone Marrow↗
[Lumbar symptoms among semi-skilled construction workers in Copenhagen].
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Adult↗
Human cytomegalovirus infection: recent developments in diagnosis and epidemiology.
Cytomegalic inclusion disease (CID) is caused by a horizontally or vertically transmitted human herpes virus infection and may persist for life without obvious clinical symptoms. A serious course of horizontal primary and recurrent infections, however, is often observed in immunocompromised persons such as recipients of organ transplants and patients receiving fresh blood transfusions. Vertical infection may cause fetopathies. The human cytomegalovirus (HCMV) is thought to inherit an oncogenic potential as lately discussed for AIDS and M. Kaposi. Laboratory diagnosis of HCMV infection is performed by light microscopy (inclusion bodies), electron microscopy, virus isolation in cell culture, demonstration of viral DNA and antigen in clinical specimens, by histochemical methods (e.g. immunoperoxidase technique) and by DNA and peptide analysis for identification of different isolates and viral finger prints. Evaluation of cell-mediated immunity in HCMV infection is performed quantitatively (assessment of Thelper/Tsuppressor ratios) or qualitatively (specific lymphocyte stimulation by the antigen). In most cases laboratory diagnosis is achieved by serological methods, i.e. demonstration and quantitation of HCMV-specific antibodies. In this context, a number of liquid- and solid-phase immunoassays have been developed, of which immunofluorescence and ELISA are most commonly used, besides complement fixation and passive haemagglutination. These procedures on the one hand allow the use of different antigen preparations as early and late viral proteins, and on the other hand permit a specific determination of different Ig classes and subclasses. A variety of assays has been established especially for determination of virus-specific IgM antibodies, which are predominantly found in active infection. These, however, at least in part may show non-specific results caused by interference of rheumatoid factor or IgG competition. Such problems have now been dealt with and are avoided by IgG precipitation or IgM immunosorption ("mu-capture" technique). These recent methods allow an exact epidemiological identification of risk groups for CMV infection. Results from our laboratory revealed 13% HCMV-IgM positive patients among pregnant women, 16% IgM positive patients among renal transplant recipients, 4% IgM positive cases in patients after cardiosurgery and 1.7% IgM positives among prostitutes. The prevalence of HCMV infection as indicated by specific IgG antibodies was 56%, 90%, 83%, and 90%, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
Acquired Immunodeficiency Syndrome↗
la-positive T lymphocytes are the producer cells of interferon gamma.
The production of gamma-interferon (IFN gamma) in human peripheral blood T lymphocytes was induced by stimulation with PHA. For identification of the producer cell of IFN gamma, double fluorescence studies were undertaken and titers of interferon were determined in preparatively separated T-cell subpopulations reactive with one of the monoclonal antibodies OKT3, OKT4, OKT8, and OKIal . Production of IFN gamma was found in OKT3+, OKT4+, and OKT8+ cells. However, IFN gamma production occurred only in T cells also reactive with the monoclonal antibody OKIal . Addition of macrophages had no substantial effect on interferon titers in these subpopulations. It is suggested that the T cell subset producing IFN gamma is characterized by its reactivity with the monoclonal antibodies OKT3, OKT4 or OKT8, and OKIal .
Antibodies, Monoclonal↗
Replication of herpes simplex virus in human T lymphocytes: characterization of the viral target cell.
Herpes simplex virus (HSV) replicated in mitogen-stimulated human T cells. Virus replication was obtained in highly enriched mitogen-stimulated T cells of the OKT 3+, OKT 4+, or OKT 8+ subtype, in stimulated B cells, and in macrophages precultured for 7 days. In contrast, no virus replication was obtained in unstimulated T or B cells, in macrophages grown in culture for 1 day, in Null/NK cells, or in granulocytes. Infectious center assays revealed that below 1% of the infected T cell subpopulations supported virus replication, whereas up to 42% of infected B cells and 80% of macrophages cultured for 1 wk were able to replicate HSV. By indirect double immunofluorescence studies, complement-mediated mass cytolysis, and positive selection experiments, it was shown that only T cells expressing Ia antigen actively replicated the virus. T cells activated in the mixed lymphocyte culture and with UV-inactivated HSV were also susceptible to HSV infection. Several human leukocyte cell lines were tested for their ability to support virus replication and were tested for a correlation with the expression of Ia antigen. Only cell lines expressing Ia antigen on more than about 5% of the total population produced new progeny virus. Ia-expressing T cells that spontaneously replicated HSV without any mitogenic prestimulation were found to occur in variable numbers in human cord blood. It is suggested, that such T cells, permissive for HSV replication, might contribute to an outspread of viral infection in vivo.
Antibodies, Viral↗
Replication of herpes simplex virus in human T lymphocytes.
The replication of herpes simplex virus (HSV) in cultures of human T lymphocytes was investigated. Virus replication occurred only in lymphocyte cultures prestimulated with mitogen. At least one of the factors responsible for this phenomenon is adsorption of the virus to the cells, which was 5 times less efficient in nonstimulated cells than in stimulated cultures. Growth of virus in infected cultures was restricted to lymphocytes of T origin. This was shown by successful infection of highly purified T-cell cultures and by virus replication in four continuous T-cell lines. No virus production was obtained in cultures of lymphocytes of other than T-cell origin. Virus titers in T-lymphocyte cultures reached 10(7) PFU/ml, which was a four log10 step increase over the input dose. Lymphocytes infected with a syn strain of HSV, HSV-ANG, induced polykaryocyte formation in the cultures and therefore generated a CPE visible by microscopic examination. Infection with syn+ strains of HSV (i.e., strains which do not cause cell fusion) did not lead to such phenomena. Not more than 1% of infected T cells was replicating HSV, as revealed by infectious center assays. In contrast, about 5% of these cells showed positive immunofluorescence with anti-HSV antibodies, indicating the presence of cells which express viral protein but do not actively produce infectious virus.
Antigens, Viral↗
Rapid separation of T cell subpopulations with monoclonal antibodies and affinity chromatography.
A rapid method for isolation of highly enriched helper and suppressor T cell subsets and their corresponding helper and suppressor cell depleted cell populations is described. The method is based on the binding of monoclonal antibodies to helper and suppressor cells and subsequent affinity chromatography with covalently bound rabbit anti-mouse antibodies. As assessed by indirect immunofluorescence, purity of the enriched subpopulations exceeds 90%, whereas no contamination with helper or suppressor cells is detectable in populations depleted of the respective subsets. The cells isolated by this method show no functional defects in helper and suppressor assays and respond with increased DNA synthesis to stimulation with phytohemagglutinin (PHA) plus 2-mercaptoethanol (2-ME).
Animals↗
Alterations in protein and glycoprotein composition of rat embryo fibroblasts transformed by herpes simplex virus type 2.
Total and superficially exposed plasma membrane components of tumorigenic herpes-simplex-virus (HSV)-transformed fibroblasts were studied. As a result of oncogenic HSV transformation, a significant decrease of polypeptides 230,000, 180,000, 56,000 and 43,000 daltons was found. These changes were accompanied by a significant increase in superficial exposition of several sialopeptides and two peptides of 30,000 and 15,000 daltons. It was suggested that these two peptides may represent virus-coded components of HSV-transformed fibroblasts. The present results indicate that the HSV-transformed tumorigenic cell clone meets all previously described criteria for oncogenically transformed cells.
Animals↗