Protective Immunity and New Vaccines for Lyme Disease.

Lyme disease, caused by some Borrelia burgdorferi sensu lato, is the most common tick-borne illness in the Northern Hemisphere and the number of cases, and geographic spread, continue to grow. Previously identified B. burgdorferi proteins, lipid immunogens, and live mutants lead the design of canonical vaccines aimed at disrupting infection in the host. Discovery of the mechanism of action of the first vaccine catalyzed the development of new strategies to control Lyme disease that bypassed direct vaccination of the human host. Thus, novel prevention concepts center on proteins produced by B. burgdorferi during tick transit and on tick proteins that mediate feeding and pathogen transmission. A burgeoning area of research is tick immunity as it can unlock mechanistic pathways that could be targeted for disruption. Studies that shed light on the mammalian immune pathways engaged during tick-transmitted B. burgdorferi infection would further development of vaccination strategies against Lyme disease.

Whole-genome sequences of Odocoileus hemionus deer adenovirus isolates from deer, moose and elk are highly conserved and support a new species in the genus Atadenovirus.

We present the first complete genome sequence of Odocoileus hemionus deer adenovirus 1 (OdAdV-1). This virus can cause sporadic haemorrhagic disease in cervids, although epizootics with high mortality have occurred in California. OdAdV-1 has been placed in the genus Atadenovirus, based on partial hexon, pVIII and fibre genes. Ten field isolates recovered from naturally infected mule deer (Odocoileus hemionus), white-tailed deer (Odocoileus virginiana) and moose (Alces alces) from Wyoming, black-tailed deer (Odocoileus hemionus columbianus) from California, and Rocky Mountain elk (Cervus elaphus nelsoni) from Colorado and Washington state were sequenced. The genome lengths ranged from 30 620 to 30 699 bp, contained the predicted proteins and gene organization typical of members of genus Atadenovirus, and had a high percentage of A/T nucleotides (66.7 %). Phylogenic analysis found that the closest ancestry was with ruminant atadenoviruses, while a divergence of the hexon, polymerase and penton base proteins of more than 15 % supports classification as a new species. Genetic global comparison between the 10 isolates found an overall 99 % identity, but greater divergence was found between those recovered from moose and elk as compared to deer, and a single variable region contained most of these differences. Our findings demonstrate that OdAdV-1 is highly conserved between 10 isolates recovered from multiple related cervid species, but genotypic differences, largely localized to a variable region, define two strains. We propose that the virus type name be changed to cervid adenovirus 1, with the species name Cervid atadenovirus A. Sequence data were used to develop molecular assays for improved detection and genotyping.

Phenotype-based identification of host genes required for replication of African swine fever virus.

African swine fever virus (ASFV) produces a fatal acute hemorrhagic fever in domesticated pigs that potentially is a worldwide economic threat. Using an expressed sequence tag (EST) library-based antisense method of random gene inactivation and a phenotypic screen for limitation of ASFV replication in cultured human cells, we identified six host genes whose cellular functions are required by ASFV. These included three loci, BAT3 (HLA-B-associated transcript 3), C1qTNF (C1q and tumor necrosis factor-related protein 6), and TOM40 (translocase of outer mitochondrial membrane 40), for which antisense expression from a tetracycline-regulated promoter resulted in reversible inhibition of ASFV production by >99%. The effects of antisense transcription of the BAT3 EST and also of expression in the sense orientation of this EST, which encodes amino acid residues 450 to 518 of the mature BAT3 protein, were investigated more extensively. Sense expression of the BAT3 peptide, which appears to reversibly interfere with BAT3 function by a dominant negative mechanism, resulted in decreased synthesis of viral DNA and proteins early after ASFV infection, altered transcription of apoptosis-related genes as determined by cDNA microarray analysis, and increased cellular sensitivity to staurosporine-induced apoptosis. Antisense transcription of BAT3 reduced ASFV production without affecting abundance of the virus macromolecules we assayed. Our results, which demonstrate the utility of EST-based functional screens for the detection of host genes exploited by pathogenic viruses, reveal a novel collection of cellular genes previously not known to be required for ASFV infection.