flu
[Vaccination against influenza in elderly persons: some current presumptions]

[Article in French]

Roy G, Fradet M, Le Henaff D.

Centre de sante publique de Quebec.

A telephone survey in March 1994 revealed that only 70% of 185 persons surveyed aged 65 and over were offered influenza vaccine during the last flu shot campaign; the sample was taken among non-institution residents of the Quebec City area who were likely to have regular health professional contact. Misinformation concerning influenza infection and vaccine remains widespread: 30% of the people surveyed still believe that the vaccine can transmit the virus and 21% consider the vaccine ineffective. Incorrect beliefs are significantly more prevalent among the unvaccinated population: 12% stated that they were allergic to the vaccine; in fact, true allergies are rare. Health professionals should recognize that elderly people, though in regular contact with the health care system, may not have been offered the influenza vaccine and may have inadequate information or incorrect beliefs regarding influenza and its preventability.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8991750&dopt=Abstract flu, flu medicine, tamiflu



flu
Nonpolarized distribution of glycosylphosphatidylinositols in the plasma membrane of polarized Madin-Darby canine kidney cells.

van't Hof W, Rodriguez-Boulan E, Menon AK.

Department of Cell Biology and Anatomy, Cornell University Medical College, New York, New York 10021, USA.

Glycosylphosphatidylinositols (GPIs) are ubiquitous in eukaryotes and serve to anchor a variety of proteins to the exoplasmic leaflet of cellular membranes. GPIs are synthesized in the endoplasmic reticulum (ER), in excess of the amount needed for protein modification. The fate of the excess GPIs is unknown, but they may be retained in the ER, transported to other membranes, and/or metabolized. In relation to this problem, we were interested in determining whether GPIs were transported to the plasma membrane and whether, like GPI-anchored proteins, their presence was confined to the apical plasma membrane domain in polarized epithelial cells. Polarized Madin-Darby canine kidney epithelial cell monolayers were incubated with [3H]mannose or [3H]ethanolamine to label GPIs and then infected with enveloped viruses. We used influenza virus (flu) and vesicular stomatitis virus (VSV) for these experiments as these viruses are assembled at the cell surface and acquire their envelope lipids from the plasma membrane. Furthermore, flu and VSV bud specifically from the apical and basolateral plasma membrane domains, respectively. Flu and VSV were isolated from the apical and basolateral media, respectively, and subjected to lipid analysis. Radiolabeled GPIs were found in both viruses. Moreover, the membrane concentration of GPIs (i.e. GPI radioactivity normalized to membrane mass) in the two viruses was essentially the same. These observations suggest that (i) non-protein-linked GPIs are located at the plasma membrane; (ii) since GPIs are synthesized in the ER, they must be transported from the ER to the plasma membrane; and (iii) transport of nonprotein-linked GPIs is not influenced by the sorting processes that target GPI-anchored proteins exclusively to the apical plasma membrane.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7592618&dopt=Abstract flu, flu medicine, tamiflu



flu
Effects of a minor isoleucyl tRNA on heterologous protein translation in Escherichia coli.

Del Tito BJ Jr, Ward JM, Hodgson J, Gershater CJ, Edwards H, Wysocki LA, Watson FA, Sathe G, Kane JF.

Department of Biopharmaceutical Quality Operations, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406-0939, USA.

In Escherichia coli, the isoleucine codon AUA occurs at a frequency of about 0.4% and is the fifth rarest codon in E. coli mRNA. Since there is a correlation between the frequency of codon usage and the level of its cognate tRNA, translational problems might be expected when the mRNA contains high levels of AUA codons. When a hemagglutinin from the influenza virus, a 304-amino-acid protein with 12 (3.9%) AUA codons and 1 tandem codon, and a mupirocin-resistant isoleucyl tRNA synthetase, a 1,024-amino-acid protein, with 33 (3.2%) AUA codons and 2 tandem codons, were expressed in E. coli, product accumulation was highly variable and dependent to some degree on the growth medium. In rich medium, the flu antigen represented about 16% of total cell protein, whereas in minimal medium, it was only 2 to 3% of total cell protein. In the presence of the cloned ileX, which encodes the cognate tRNA for AUA, however, the antigen was 25 to 30% of total cell protein in cells grown in minimal medium. Alternatively, the isoleucyl tRNA synthetase did not accumulate to detectable levels in cells grown in Luria broth unless the ileX tRNA was coexpressed when it accounted for 7 to 9% of total cell protein. These results indicate that the rare isoleucine AUA codon, like the rare arginine codons AGG and AGA, can interfere with the efficient expression of cloned proteins.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8522513&dopt=Abstract flu, flu medicine, tamiflu



flu
[Application of the IFN-gamma ELISPOT assay for monitoring CD8(+) T cell response to specific antigen from hepatocellular carcinoma patients]

[Article in Chinese]

Pang X, Shang X, Lu J.

Department of Immunology, Peking University Health Science Center, Beijing 100083, China.

OBJECTIVE: To study the specific CD8(+) T cell response to HLA-A2 binding peptide Flu p58-66 from HLA-A2-positive hepatocellular carcinoma patients and healthy donors. METHODS: The CD8(+) T cells were separated with immunobeads from PBMC of HCC patients and healthy donors, respectively. The irradiated autologous CD8(-) PBMC or isolated dendritic cells were loaded with influenza matrix peptide as APC. After 7 days' culture, the frequency of effector cells to secrete IFN-gamma in response to Flu p58-66 was detected in ELISPOT assay. RESULTS: With CD8(-) PBMC as APC, the frequency of effector cells to secrete IFN-gamma in response to Flu peptide was 22 +/- 9/well in HCC patients (n = 8) and 59 +/- 27/well in healthy donors (n = 12) when the effector cells were 5 x 10(4)/well (P < 0.01). To compare the antigen-presenting capacity of APC derived from 5 healthy donors, DC was better than CD8(-) PBMC. CONCLUSION: Although the frequency of specific effector CTL to secrete IFN-gamma in response to Flu p58 - 66 was lower in HCC patients than in healthy individuals, the majority of HCC patients have the cellular immunity specific to antigen peptides.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11825525&dopt=Abstract flu, flu medicine, tamiflu



flu
The CARE telematics network for the surveillance of influenza in Europe.

Snacken R, Bensadon M, Strauss A.

Institute for Hygiene and Epidemiology, Department of Epidemiology, Brussels, Belgium.

Since the 1950s, national networks for the surveillance of influenza have been progressively implemented in several countries. New epidemiological arguments have triggered changes in order to increase the sensitivity of existent early warning systems and to strengthen the communications between European networks. The WHO project CARE Telematics, which collects clinical and virological data of nine national networks and sends useful information to public health administrations, is presented. From the results of the 1993-94 season, the benefits of the system are discussed. Though other telematics networks in this field already exist, it is the first time that virological data, absolutely essential for characterizing the type of an outbreak, are timely available by other countries. This argument will be decisive in case of occurrence of a new strain of virus (shift), such as the Spanish flu in 1918. Priorities are now to include other existing European surveillance networks.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8713768&dopt=Abstract flu, flu medicine, tamiflu



flu
Evaluation of Directigen Flu A assay for detection of influenza antigen in nasal secretions of horses.

Morley PS, Bogdan JR, Townsend HG, Haines DM.

Department of Veterinary Internal Medicine, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.

The Directigen Flu A assay (Becton Dickinson, Microbiology Systems, Mississauga, Ontario, Canada) is a commercially available immunoassay designed for rapid in vitro recognition of influenza A nucleoprotein. The purpose of this study was to evaluate this assay for detection of influenza virus in nasal secretions of naturally infected horses. The assay was shown to react with representative strains of influenza virus which cause disease in horses and did not react with nasal secretions from uninfected horses kept in isolation. Between 33% and 45% of nasal secretions specimens obtained from clinically diseased horses during influenza epidemics reacted positively in the assay and 95% to 98% of horses not showing signs of disease during influenza epidemics tested negative. In contrast, influenza virus was isolated from only 7% of diseased horses using conventional techniques. Diseased horses which were positive in the Directigen assay had lower pre-exposure influenza antibody concentrations and showed more clinical signs than diseased Directigen-negative horses. This evaluation demonstrates that the Directigen Flu A assay detects influenza virus in nasal secretions of infected horses and is more sensitive than virus isolation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7607146&dopt=Abstract flu, flu medicine, tamiflu