Intervirology

Background/Aims: Coronavirus (CoV) infections induce respiratory tract illnesses and central nervous system (CNS) diseases. We aimed to explore the cytokine expression profiles in hospitalized children with CoV-CNS and CoV-respiratory tract infections. Methods: A total of 183 and 236 hospitalized children with acute encephalitis-like syndrome and respiratory tract infection, respectively, were screened for anti-CoV IgM antibodies. The expression profiles of multiple cytokines were determined in CoV-positive patients. Results: Anti-CoV IgM antibodies were detected in 22/183 (12.02%) and 26/236 (11.02%) patients with acute encephalitis-like syndrome and respiratory tract infection, respectively. Cytokine analysis revealed that the level of serum granulocyte colony-stimulating factor (G-CSF) was significantly higher in both CoV-CNS and CoV-respiratory tract infection compared with healthy controls. Additionally, the serum level of granulocyte macrophage colony-stimulating factor (GM-CSF) was significantly higher in CoV-CNS infection than in CoV-respiratory tract infection. In patients with CoV-CNS infection, the levels of IL-6, IL-8, MCP-1, and GM-CSF were significantly higher in their cerebrospinal fluid samples than in matched serum samples. Conclusion: To the best of our knowledge, this is the first report showing a high incidence of CoV infection in hospitalized children, especially with CNS illness. The characteristic cytokine expression profiles in CoV infection indicate the importance of host immune response in disease progression.

Since the isolation of the first giant virus, the Mimivirus, by T.J. Rowbotham in a cooling tower in Bradford, UK, and after its characterisation by our group in 2003, we have continued to develop novel strategies to isolate additional strains. By first focusing on cooling towers using our original time-consuming procedure, we were able to isolate a new lineage of giant virus called Marseillevirus and a new Mimivirus strain called Mamavirus. In the following years, we have accumulated the world's largest unique collection of giant viruses by improving the use of antibiotic combinations to avoid bacterial contamination of amoeba, developing strategies of preliminary screening of samples by molecular methods, and using a high-throughput isolation method developed by our group. Based on the inoculation of nearly 7,000 samples, our collection currently contains 43 strains of Mimiviridae (14 in lineage A, 6 in lineage B, and 23 in lineage C) and 17 strains of Marseilleviridae isolated from various environments, including 3 of human origin. This study details the procedures used to build this collection and paves the way for the high-throughput isolation of new isolates to improve the record of giant virus distribution in the environment and the determination of their pangenome.

<i>Objective:</i> Porcine endogenous retroviruses (PERVs) are of particular concern with xenotransplantations using pig cells, tissues or organs as they are present in the genome of all pig strains and are able to infect human cells in vitro. However, it remains unclear whether PERV particles will be produced in vivo and whether they may infect xenotransplant recipients. Since normal pig peripheral blood mononuclear cells (PBMCs) may be transmitted together with the transplanted organ, the production of PERVs by stimulated PBMCs was studied in vitro. <i>Methods:</i> To simulate antigen-induced activation of PBMCs, phytohaemagglutinin (PHA), a T cell mitogen, and the phorbol ester O-tetradecanoylphorbol-13-acetate (TPA), a tumour promoter, were used. Virus release was estimated by measuring reverse transcriptase (RT) activity and by RT-PCR of pelleted viruses. <i>Results:</i> Treatment of pig PBMCs with PHA or TPA induced the release of PERVs. For the first time, a correlation between the extent of proliferation of pig PBMCs and PERV production was shown. In addition, PERV release by non-proliferating cells and differences in virus production between stimuli as well as between different pig strains and individuals of one strain were observed. Subtype analysis revealed the release of the three subtypes PERV-A, PERV-B and PERV-C. In contrast to murine endogenous retroviruses, PERVs were induced by PHA alone. <i>Conclusion:</i> The data suggest that the PBMCs transmitted within a xenotransplant may release PERV. These data also suggest that pig strains producing low amounts of virus could be more suitable for xenotransplantation.