Susceptibility of Human Lymphoid Tissue Cultured ex vivo to Xenotropic Murine Leukemia Virus-Related Virus (XMRV) Infection

BACKGROUND: Xenotropic murine leukemia virus-related virus (XMRV) was generated after a recombination event between two endogenous murine leukemia viruses during the production of a prostate cancer cell line. Although the associations of the XMRV infection with human diseases appear unlikely, the XMRV is a retrovirus of undefined pathogenic potential, able to replicate in human cells in vitro. Since recent studies using animal models for infection have yielded conflicting results, we set out an ex vivo model for XMRV infection of human tonsillar tissue to determine whether XMRV produced by 22Rv1 cells is able to replicate in human lymphoid organs. Tonsil blocks were infected and infection kinetics and its pathogenic effects were monitored RESULTS: XMRV, though restricted by APOBEC, enters and integrates into the tissue cells. The infection did not result in changes of T or B-cells, immune activation, nor inflammatory chemokines. Infectious viruses could be recovered from supernatants of infected tonsils by reinfecting DERSE XMRV indicator cell line, although these supernatants could not establish a new infection in fresh tonsil culture, indicating that in our model, the viral replication is controlled by innate antiviral restriction factors. CONCLUSIONS: Overall, the replication-competent retrovirus XMRV, present in a high number of laboratories, is able to infect human lymphoid tissue and produce infectious viruses, even though they were unable to establish a new infection in fresh tonsillar tissue. Hereby, laboratories working with cell lines producing XMRV should have knowledge and understanding of the potential biological biohazardous risks of this virus

Characterization of flagella of Clostridium difficile and their role in serogrouping reactions.

Slide agglutination with rabbit antisera allows the differentiation of 10 serogroups of Clostridium difficile, namely, A, B, C, D, F, G, H, I, K, and X. Each serogroup displays a specific protein profile in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, except for A, which displays 12 different protein profiles (A1 to A12). In the present work, electron microscopy revealed the presence of uniformly distributed flagella in the reference strains of serogroups G and K and in all strains representative of the 12 subgroups within serogroup purified by differential centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these preparations revealed one distinct band with an apparent molecular mass of approximately 39 kilodaltons. Antiserum was prepared by immunizing a rabbit with the serogroup A flagellin, which had been eluted from the gel. In immunoblotting, this antiserum cross-reacted with the flagellin of the other strains. When the cells were deflagellated by a short sonication, the cross-reactions observed by slide agglutination with A, G, and K antisera were suppressed. Similarly, shearing of flagella allowed specific slide agglutination of the 12 subgroups of serogroup A

Evidence for persistence of human parvovirus B19 DNA in bone marrow

A nested polymerase chain reaction assay (nPCR) was used to investigate the potential of human parvovirus B19 DNA to persist in blood or bone marrow samples obtained either from blood donors or cadaveric bone donors or from patients presenting with clinical signs of parvovirus B19 infection. The presence of parvovirus B19 specific antibody in blood was tested by enzyme immunoassay (EIA). B19 virus genome was not detected in any blood sample of 115 blood donors, of whom 92 (80%) had anti-B19 IgG antibody only as an indication of past infection. In contrast, B19 virus DNA was detected in the bone marrow of 4 out of 45 bone donors. Each one of the serum samples available for 3 of these 4 individuals contained anti-B19 IgG antibody. Among 84 patients with clinical manifestations of parvovirus B19 infection, 17 (20%) had B19 virus DNA in bone marrow. Eight of the latter patients had anti-B19 IgG antibody in their blood but neither anti-B19 IgM nor B19 virus DNA. These data document the ability of parvovirus B19 DNA to persist in the bone marrow of asymptomatic individuals and patients with parvovirus B19 infection suspected on clinical grounds. (C) 1997 Wiley-Liss, Inc

Canine hemorrhagic enteritis: Detection of viral particles by electron microscopy

At necropsy, several dogs which died showing symptoms of hemorrhagic diarrhea, had significant lesions of the mucosa that were found especially in the duodenum and upper part of the small bowel. Study of ultrathin sections from the diseased mucosa revealed particles resembling parvoviruses in altered nuclei of cells of the intestinal crypts. Electron microscopic examination of intestinal contents by negative staining has shown the presence of many viral particles which have a diameter of 24 nm and whose profile is consistent with an icosahedral shape. These virions float at a density of 1.43 g/cm3 in cesium chloride and agglutinate rhesus monkey and swine red blood cells at 4° C. A possible etiological role in discussed. This virus is compared with the minute virus of canines and the Feline Panleukopenia virus. © 1979 Springer-Verlag

Disseminated BCG in HIV infection.

A boy, born to a mother with AIDS related complex, was immunised with BCG on the 10th day of life. At the age of 4 months he presented with a local enlarged lymph node, fever, hypotonia, and diarrhoea. Mycobacterium bovis, BCG strain, was grown from the lymph node and cerebrospinal fluid; this proved dissemination

Standardized method of Sendai virus production for biological assays

A method for the production and purification of Sendai virus is described