Immunomodulatory Proteins of Orthopoxviruses

The review considers recent data on the structural–functional organization of the genome of orthopoxviruses pathogenic for humans, including the variola, monkeypox, cowpox, and vaccinia viruses. Emphasis was placed on the structure of molecular virulence factors that suppress the inflammatory reactions, immune response, and interferon effects induced by virus infection.     

Expression of genes for orthopoxviral TNF-binding proteins in insect cells and investigation of the recombinant TNF-binding proteins

Genes for TNF-binding proteins (CrmBs) of the variola virus (VARV), monkeypox virus (MPXV) or cowpox virus (CPXV) were isolated by PCR from viral genomes and expressed in a baculovirus system in the Sf21 insect cell line. Properties of the purified recombinant proteins were studied by various physicochemical and immunological methods. Using solid-phase enzyme-linked immunosorbent assay, it was shown that viral proteins inhibited hTNF binding with polyclonal anti-hTNF antibodies, with the efficiency of inhibition decreasing in the series VARV-CrmB > CPXV-CrmB > MPXV-CrmB. Biological activity of the recombinant protein preparations was assessed by their ability to neutralize TNF cytotoxicity on the L929 murine fibroblast cells line. CrmBs were shown to neutralize cytotoxicity of human, mouse, and rabbit TNF in a species-specific manner. It was also shown that the efficiency of VARV-CrmB in inhibiting hTNF cytotoxicity exceeded that of polyclonal anti-hTNF antibodies. Orthopoxviral CrmB proteins can provide a basis for development of new anti-TNF drugs.__________Translated from Molekulyarnaya Biologiya, Vol. 39, No. 2, 2005, pp. 245–254.Original Russian Text Copyright © 2005 by Gileva, Ryazankin, Nepomnyashchikh, Totmenin, Maxutov, Lebedev, Afinogenova, Pustoshilova, Shchelkunov.     

Discovery of a New Class of Inhibitors of Vaccinia Virus Based on (−)‐Borneol from Abies sibirica and (+)‐Camphor

A series of the bornyl ester/amide derivatives with N‐containing heterocycles were designed and synthesized as vaccinia virus (VV) inhibitors. Bioassay results showed that among the designed compounds, derivatives 6 , 13 , 14 , 34 , 36 and 37 showed the best inhibitory activity against VV with the IC₅₀ values of 12.9, 17.9, 3.4, 2.5, 12.5 and 7.5 μm , respectively, and good cytotoxicity. The primary structure–activity relationship (SAR) study suggested that the combination of a saturated N‐heterocycle, such as morpholine or 4‐methylpiperidine, and a 1,7,7‐trimethylbicyclo[2.2.1]heptane scaffold was favorable for antiviral activity.     

Orthopoxvirus Genes for Kelch-like Proteins: I. Analysis of Species-Specific Structural Features

Genes and proteins of the kelch superfamily were structurally analyzed in the smallpox (SPV), monkeypox, cowpox (CPV), and vaccinia viruses. Genes potentially coding for the kelch-like proteins were found only in the variable terminal regions of the orthopoxvirus genome. The set and sizes of their protein products varied with species. All genes of the superfamily proved to be disrupted by mutations in SPV, which is highly pathogenic for its only host, man. The largest set of kelch-like proteins was observed for CPV, which is low-pathogenic for humans and has the broadest animal host range. The kelch-like proteins of one virus showed low homology to each other, whereas isologs of different viruses were highly homologous. The results testified to the earlier assumption that CPV is the most ancient representative and an ancestor of the other orthopoxviruses pathogenic for humans.