Transcriptomic profile of host response in Japanese encephalitis virus infection

Background

The attenuated Yellow fever (YF) 17D vaccine virus is one of the safest and most effective viral vaccines administered to humans, in which it elicits a polyvalent immune response. Herein, we used the YF 17D backbone to express a Trypanosoma cruzi CD8⁺ T cell epitope from the Amastigote Surface Protein 2 (ASP-2) to provide further evidence for the potential of this virus to express foreign epitopes. The TEWETGQI CD8⁺ T cell epitope was cloned and expressed based on two different genomic insertion sites: in the fg loop of the viral Envelope protein and the protease cleavage site between the NS2B and NS3. We investigated whether the site of expression had any influence on immunogenicity of this model epitope.

Results

Recombinant viruses replicated similarly to vaccine virus YF 17D in cell culture and remained genetically stable after several serial passages in Vero cells. Immunogenicity studies revealed that both recombinant viruses elicited neutralizing antibodies to the YF virus as well as generated an antigen-specific gamma interferon mediated T-cell response in immunized mice. The recombinant viruses displayed a more attenuated phenotype than the YF 17DD vaccine counterpart in mice. Vaccination of a mouse lineage highly susceptible to infection by T. cruzi with a homologous prime-boost regimen of recombinant YF viruses elicited TEWETGQI specific CD8⁺ T cells which might be correlated with a delay in mouse mortality after a challenge with a lethal dose of T. cruzi.

Conclusions

We conclude that the YF 17D platform is useful to express T. cruzi (Protozoan) antigens at different functional regions of its genome with minimal reduction of vector fitness. In addition, the model T. cruzi epitope expressed at different regions of the YF 17D genome elicited a similar T cell-based immune response, suggesting that both expression sites are useful. However, the epitope as such is not protective and it remains to be seen whether expression of larger domains of ASP-2, which include the TEWETGQI epitope, will elicit better T-CD8+ responses to the latter. It is likely that additional antigens and recombinant virus formulations will be necessary to generate a protective response.     

Nitrated nucleosome levels and neuropsychiatric events in systemic lupus erythematosus; a multi-center retrospective case-control study

Background

In patients with systemic lupus erythematosus (SLE) there is no serological test that will reliably distinguish neuropsychiatric (NP) events due to active SLE from those due to other causes. Previously we showed that serum levels of nitrated nucleosomes (NN) were elevated in a small number of patients with NPSLE. Here we measured serum NN in samples from a larger population of patients with SLE and NP events to see whether elevated serum NN could be a marker for NPSLE.

Methods

We obtained serum samples from patients in the Systemic Lupus International Collaborative Clinics (SLICC) inception cohort. This included 216 patients with NP events and two matched controls with SLE but no NP events for each of these patients. For the NP patients we tested samples taken before, during and after the NP event.

Results

Twenty-six patients had events attributed to SLE according to the most stringent SLICC attribution rule. In these patients there was no association between onset of event and elevated serum NN. In 190 patients in whom events were not attributed to SLE by the SLICC rules, median serum NN was elevated at the onset of event (P?=?0.006). The predominant clinical features in this group of 190 patients were headache, mood disorders and anxiety.

Conclusions

Serum NN levels rise at the time of an NP event in a proportion of patients with SLE. Further studies are needed to determine the value of serum NN as a biomarker for NPSLE.

     

Scanning conductance microscopy investigations on fixed human chromosomes

Scanning conductance microscopy investigations were carried out in air on human chromosomes fixed on pre-fabricated SiO2 surfaces with a backgate. The point of the investigation was to estimate the dielectric constant of fixed human chromosomes in order to use it for microfluidic device optimization. The phase shift caused by the electrostatic forces, together with geometrical measurements of the atomic force microscopy (AFM) cantilever and the chromosomes were used to estimate a value for the dielectric constant of different human chromosomes.     

Complementation of α-thalassaemia in α-globin Knockout Mice with a 191 kb Transgene Containing the Human α-Globin Locus

alpha-thalassaemia is an inherited blood disorder caused by a decrease in the synthesis of alpha-globin due to mutations in one or both of the alpha-globin genes located on human chromosome 16. A 191 kb transgene derived from a sequenced bacterial artificial chromosome (BAC) clone carrying the human alpha-globin gene cluster, together with about 100 kb of sequence upstream of DNase1 hypersensitive site HS-40 and 30 kb downstream of the alpha1-globin gene, was introduced into fertilised mouse oocytes by pronuclear microinjection. Three transgenic founder mice were obtained. Analysis of one transmitting line by fluorescent in situ hybridisation and quantitative PCR demonstrated a single copy integration of the human alpha-globin transgene on chromosome 1. Analysis of haemoglobins from the peripheral blood by cellulose acetate electrophoresis and high performance liquid chromatography (HPLC) demonstrated synthesis of human alpha-globin to about 36% of the level of each mouse alpha-globin locus. Breeding of transgenic mice with mice heterozygous for a knockout (KO) deletion of both murine alpha-globin genes showed that the human alpha-globin locus restored haemoglobin levels and red cell distribution width to normal in double heterozygous mice and significantly normalised other haematological parameters. Interestingly the human transgene also induced a significant increase in red cell production and haematocrit above wild type values. This is the first report demonstrating complementation of a murine alpha-globin KO mutation by human alpha-globin gene expression from an intact human alpha-globin locus. The transgenic mouse model described in this report should be very useful for the study of human alpha-globin gene regulation and for the development of strategies to down regulate alpha-globin production as a means of ameliorating the severity of beta-thalassaemia.     

Multidrug permeases and subcellular cholesterol transport

Studies of Niemann-Pick C (NPC) and Tangier diseases have led to the identification of the causative genes, NPC1 and ABCA1, respectively. Characterization of their protein products shows that NPC1 and ABCA1 are permeases that belong to two different superfamilies of efflux pumps, which might be important in subcellular lipid and cholesterol transport.