The contribution of systemic and pulmonary immune effectors to vaccine-induced protection from H5N1 influenza virus infection.

Live attenuated influenza vaccines (LAIVs) are effective in providing protection against influenza challenge in animal models and in preventing disease in humans. We previously showed that LAIVs elicit a range of immune effectors and that successful induction of pulmonary cellular and humoral immunity in mice requires pulmonary replication of the vaccine virus. An upper respiratory tract immunization (URTI) model was developed in mice to mimic the human situation, in which the vaccine virus does not replicate in the lower respiratory tract, allowing us to assess the protective efficacy of an H5N1 LAIV against highly pathogenic H5N1 virus challenge in the absence of significant pulmonary immunity. Our results show that, after one dose of an H5N1 LAIV, pulmonary influenza-specific lymphocytes are the main contributors to clearance of challenge virus from the lungs and that contributions of influenza-specific enzyme-linked immunosorbent assay (ELISA) antibodies in serum and splenic CD8(+) T cells were negligible. Complete protection from H5N1 challenge was achieved after two doses of H5N1 LAIV and was associated with maturation of the antibody response. Although passive transfer of sera from mice that received two doses of vaccine prevented lethality in naive recipients following challenge, the mice showed significant weight loss, with high pulmonary titers of the H5N1 virus. These data highlight the importance of mucosal immunity in mediating optimal protection against H5N1 infection. Understanding the requirements for effective induction and establishment of these protective immune effectors in the respiratory tract paves the way for a more rational and effective vaccine approach in the future.

Testing an 'aging gene' in long-lived drosophila strains: increased longevity depends on sex and genetic background.

Molecular advances of the past decade have led to the discovery of a myriad of 'aging genes' (methuselah, Indy, InR, Chico, superoxide dismutase) that extend Drosophila lifespan by up to 85%. Despite this life extension, these mutants are no longer lived than at least some recently wild-caught strains. Typically, long-lived mutants are identified in relatively short-lived genetic backgrounds, and their effects are rarely tested in genetic backgrounds other than the one in which they were isolated or derived. However, the mutant's high-longevity phenotype may be dependent on interactions with alleles that are common in short-lived laboratory strains. Here we set out to determine whether one particular mutant could extend lifespan in long-lived genetic backgrounds in the fruit fly, Drosophila melanogaster. We measured longevity and resistance to thermal stress in flies that were transgenically altered to overexpress human superoxide dismutase (SOD) in the motorneurones in each of 10 genotypes. Each genotype carried the genetic background from a different naturally long-lived wild-caught Drosophila strain. While SOD increased lifespan on average, the effect was genotype- and sex-specific. Our results indicate that naturally segregating genes interact epistatically with the aging gene superoxide dismutase to modify its ability to extend longevity. This study points to the need to identify mutants that increase longevity not only in the lab strain of origin but also in naturally long-lived genetic backgrounds.

Catalytically-promoted analyte derivatization inside a gas chromatographic inlet.

Reported here is a preliminary assessment of the feasibility of catalyzing on-line derivatization reactions inside the inlet (i.e., the injection port) of a gas chromatograph (GC) with solid heterogeneous catalysts. The experiments described here entail the installation of candidate catalysts inside the GC inlet liner and the subsequent injection of analyte/reagent mixtures onto the catalyst beds. Two catalysts are identified, each of which clearly catalyzes one of the chosen model derivatization reactions in the inlet of a GC. This result supports our hypothesis that on-line derivatizations can, in principle, be reproducibly catalyzed inside the GC inlet by solid heterogeneous catalysts and that the presence of such catalysts in the inlet do not necessarily cause a serious loss of instrument performance or chromatographic efficiency.