Abstract: The BioHealthBase Bioinformatics Resource Center (BRC) (http://www.biohealthbase.org) is a public bioinformatics database and analysis resource for the study of specific biodefense and public health pathogens-Influenza virus, Francisella tularensis, Mycobacterium tuberculosis, Microsporidia species and ricin toxin. The BioHealthBase serves as an extensive integrated repository of data imported from public databases, data derived from various computational algorithms and information curated from the scientific literature. The goal of the BioHealthBase is to facilitate the development of therapeutics, diagnostics and vaccines by integrating all available data in the context of host-pathogen interactions, thus allowing researchers to understand the root causes of virulence and pathogenicity. Genome and protein annotations can be viewed either as formatted text or graphically through a genome browser. 3D visualization capabilities allow researchers to view proteins with key structural and functional features highlighted. Influenza virus host-pathogen interactions at the molecular/cellular and systemic levels are represented. Host immune response to influenza infection is conveyed through the display of experimentally determined antibody and T-cell epitopes curated from the scientific literature or as derived from computational predictions. At the molecular/cellular level, the BioHealthBase BRC has developed biological pathway representations relevant to influenza virus host-pathogen interaction in collaboration with the Reactome database (http://www.reactome.org).
Abstract: Gene and expression library immunization make it possible to functionally test all the gene-encoded antigens of a pathogen in a host challenge system. This comprehensive method could generate new and better vaccine candidates. We constructed expression libraries from simian immunodeficiency virus (SIV) cDNA and genetically immunize monkeys with the libraries alone or with a low dose of plasmids encoding human IL-12 and GMCSF. Eight of twelve animals in the three test groups showed some anti-SIV immune response, whereas the controls did not. Six months after priming, monkeys were intravenously challenged with virulent SIVmac251. All were infected but animals in two groups vaccinated with SIV libraries showed a trend toward lower viral-loads, mitigated clinical disease, and higher survival rates than controls. Significantly, co-administering the GMCSF and IL-12-encoding plasmids worsened these measures of protection. This preliminary study should encourage further development of library-vaccine strategies and caution the use of cytokines as adjuvants.
Abstract: 2-Amino-alpha-carboline (A alpha C) is a mutagenic and carcinogenic heterocyclic amine that is formed as a pyrolysis product during the high temperature cooking of food and the burning of tobacco. Human, rat, and mouse hepatic microsomes each catalyzed the NADPH-dependent oxidation of A alpha C to form six products separable by HPLC. The two major metabolites, which together accounted for approximately 85% of the total metabolism, were characterized by UV, fluorescence, proton magnetic resonance, and mass spectral analyses as 3-hydroxy-A alpha C and 6-hydroxy-A alpha C. The remaining 15% were judged to be N-hydroxy-A alpha C and its oxidation products, based on chromatographic and spectral comparisons with a standard, whose synthesis and characterization are also described. Although the proportions of each metabolite were similar across species and individuals, the overall rate of metabolism of A alpha C by human hepatic microsomes showed a wide interindividual variation (37-fold), with a mean activity that was comparable with that observed with rat or mouse liver microsomes. alpha-Naphthoflavone, a selective inhibitor for cytochromes P4501A1 and P4501A2, strongly inhibited formation of both ring-hydroxylation and N-oxidation products by human, rat, or mouse liver hepatic microsomes. In addition, A alpha C oxidation was strongly correlated (r = 0.98; p < 0.001) with the oxidation of 4-aminobiphenyl, a known selective substrate for human and rodent cytochromes P4501A2. Immunoblot analyses confirmed the presence of cytochromes P4501A2, and not P4501A1, in human liver microsomes. Additional studies using recombinant human cytochromes P450 show that high catalytic activity for A alpha C metabolism was associated with human cytochrome P4501A2. Lower, but significant activity was also noted for P4501A1 and P4502C10, which could have important implications for the metabolic activation of A alpha C extrahepatic tissues. Neither A alpha C metabolism nor immunoreactive cytochrome P4501A2 (or P4501A1) was detected in human pancreatic microsomes. Although further carcinogenicity and biomarker studies for A alpha C are needed, the high rate of A alpha C metabolism by human liver cytochrome P4501A2 suggests that humans with the rapid P4501A2 phenotype with may be more susceptible than rodents to this heterocyclic amine carcinogen.
