Medical Research Council

About: Medical Research Council is a government organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Malaria. The organization has 16430 authors who have published 19150 publications receiving 1475494 citations.

Toward a Comprehensive Phylogeny for Mammalian and Avian Herpesviruses

Abstract: With the aim of deriving a definitive phylogenetic tree for as many mammalian and avian herpesvirus species as possible, alignments were made of amino acid sequences from eight conserved and ubiquitously present genes of herpesviruses, with 48 virus species each represented by at least one gene. Phylogenetic trees for both single-gene and concatenated alignments were evaluated thoroughly by maximum-likelihood methods, with each of the three herpesvirus subfamilies (the Alpha-, Beta-, and Gammaherpesvirinae) examined independently. Composite trees were constructed starting with the top-scoring tree based on the broadest set of genes and supplemented by addition of virus species from trees based on narrower gene sets, to give finally a 46-species tree; branching order for three regions within the tree remained unresolved. Sublineages of the Alpha- and Betaherpesvirinae showed extensive cospeciation with host lineages by criteria of congruence in branching patterns and consistency in extent of divergence. The Gammaherpesvirinae presented a more complex picture, with both higher and lower substitution rates in different sublineages. The final tree obtained represents the most detailed view to date of phylogenetic relationships in any family of large-genome viruses.

A novel chimpanzee adenovirus vector with low human seroprevalence: improved systems for vector derivation and comparative immunogenicity.

Abstract: Recombinant adenoviruses are among the most promising tools for vaccine antigen delivery. Recently, the development of new vectors has focused on serotypes to which the human population is less exposed in order to circumvent pre-existing anti vector immunity. This study describes the derivation of a new vaccine vector based on a chimpanzee adenovirus, Y25, together with a comparative assessment of its potential to elicit transgene product specific immune responses in mice. The vector was constructed in a bacterial artificial chromosome to facilitate genetic manipulation of genomic clones. In order to conduct a fair head-to-head immunological comparison of multiple adenoviral vectors, we optimised a method for accurate determination of infectious titre, since this parameter exhibits profound natural variability and can confound immunogenicity studies when doses are based on viral particle estimation. Cellular immunogenicity of recombinant E1 E3-deleted vector ChAdY25 was comparable to that of other species E derived chimpanzee adenovirus vectors including ChAd63, the first simian adenovirus vector to enter clinical trials in humans. Furthermore, the prevalence of virus neutralizing antibodies (titre >1:200) against ChAdY25 in serum samples collected from two human populations in the UK and Gambia was particularly low compared to published data for other chimpanzee adenoviruses. These findings support the continued development of new chimpanzee adenovirus vectors, including ChAdY25, for clinical use.

A Structural Basis for Immunodominant Human T Cell Receptor Recognition

Abstract: The anti-influenza CD8+ T cell response in HLA-A2–positive adults is almost exclusively directed at residues 58–66 of the virus matrix protein (MP(58–66)). Vβ17Vα10.2 T cell receptors (TCRs) containing a conserved arginine-serine-serine sequence in complementarity determining region 3 (CDR3) of the Vβ segment dominate this response. To investigate the molecular basis of immunodominant selection in an outbred population, we have determined the crystal structure of Vβ17Vα10.2 in complex with MP(58–66)–HLA-A2 at a resolution of 1.4 A. We show that, whereas the TCR typically fits over an exposed side chain of the peptide, in this structure MP(58–66) exposes only main chain atoms. This distinctive orientation of Vβ17Vα10.2, which is almost orthogonal to the peptide-binding groove of HLA-A2, facilitates insertion of the conserved arginine in Vβ CDR3 into a notch in the surface of MP(58–66)–HLA-A2. This previously unknown binding mode underlies the immunodominant T cell response.

Probiotics and prebiotics: can regulating the activities of intestinal bacteria benefit health?

Abstract: The colonic microflora is important to health. The growth and metabolism of the many individual bacterial species inhabiting the large bowel depend primarily on the substrates available to them, most of which come from the diet. 1 2 This has led to attempts to modify the structure and metabolic activities of the community through diet—using probiotics and prebiotics. Probiotics are live microbial food supplements. The best known are the lactic acid bacteria and bifidobacteria, which are widely used in yoghurts and other dairy products (fig 1). These organisms are non-pathogenic and non-toxigenic,retain viability during storage, and survive passage through the stomach and small bowel. Prebiotics are non-digestible food ingredients which selectively stimulate the growth or activities, or both, of lactobacilli or bifidobacteria in the colon, thereby improving health. #### Summary points Fig 1 A selection of “bio” yoghurts available in supermarkets Since probiotics do not permanently colonise the host, they need to be ingested regularly for any health promoting properties to persist. Most studies on probiosis have been observational rather than mechanistic, and thus the processes responsible for many probiotic phenomena are seldom explained. Some probiotics are members of the normal colonic microflora and are not …