Biology subjects

Temperton, N. J.

Publications and source records attributed to Temperton, N. J..

22 records · Page 2Linked to original sources

bioRxiv2018

Development and use of Lentiviral Vectors Pseudotyped with Influenza B Haemagglutinins: application to vaccine immunogenicity, mAb potency and sero-surveillance studies

Influenza B viruses cause respiratory disease epidemics in human populations and are included in seasonal influenza vaccines. Serological methods are employed to evaluate vaccine immunogenicity prior to licensure. However, the haemagglutination inhibition assay, which represents the gold standard for assessing the immunogenicity of influenza vaccines, has been shown to be relatively insensitive for the detection of antibodies against influenza B viruses. Furthermore, this assay, and the serial radial haemolysis assay are not able to detect stalk-directed cross-reactive antibodies. For these reasons there is a need to develop new assays that can overcome these limitations. The use of replication-defective viruses, such as lentiviral vectors pseudotyped with influenza A haemagglutinins, in microneutralization assays is a safe and sensitive alternative to study antibody responses elicited by natural infection or vaccination. We have produced Influenza B haemagglutinin-pseudotypes using plasmid-directed transfection. To activate influenza B haemagglutinin, we have explored the use of proteases by adding relevant encoding plasmids to the transfection mixture. When tested for their ability to transduce target cells, the newly produced influenza B pseudotypes exhibit tropism for different cell lines. Subsequently the pseudotypes were evaluated as surrogate antigens in microneutralization assays using reference sera, monoclonal antibodies, human sera collected during a vaccine immunogenicity study and surveillance sera from seals. The influenza B pseudotype virus neutralization assay was found to effectively detect neutralizing and cross-reactive responses despite lack of significant correlation with the haemagglutinin inhibition assay.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=61 SRC=\"FIGDIR/small/492785_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (19K):\norg.highwire.dtl.DTLVardef@d5d8e7org.highwire.dtl.DTLVardef@1934a06org.highwire.dtl.DTLVardef@e0d0b8org.highwire.dtl.DTLVardef@1a717e0_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2017

The study of antibody responses to influenza neuraminidase using a lentiviral pseudotype based ELLA

Influenza pseudotypes represent an alternative to wild type virus for serological assays. To date, pseudotypes (PV) have predominantly been used as surrogates for wild type viruses in microneutralisation assays, where the surface glycoprotein of interest and a reporter gene (such as Luciferase) are used to assess if virus entry into target cells could be inhibited by serum antibodies. The influenza neuraminidase (NA) has the ability to bud and release new virions with or without the contribution of Haemagglutinin (HA). Influenza pseudotypes expressing NA alone, or with HA, were produced to evaluate the antibody response against NA using the enzyme-linked lectin assay (ELLA). The expression of an avian HA with human NAs has enabled the detection of specific antibody reponses against the human circulating subtypes of NA. Within this study a PV-based ELLA assay has been investigated with a pilot panel of sera prepared for an international CONSISE study. Preliminary results have confirmed that the assay is sensitive and could potentially represent a valid alternative to the classical ELLA assay, which requires the employment of reassortant viruses.

microbiology↗

bioRxiv2017

Identification of an epitope of limited variability under strong immune selection in the haemagglutinin head domain of H1N1 influenza

Antigenic targets of influenza vaccination are currently seen to be polarised between (i) highly immunogenic (and protective) epitopes of high variability, and (ii) conserved epitopes of low immunogenicity. This requires vaccines directed against the variable sites to be continuously updated, with the only other alternative being seen as the artificial boosting of immunity to invariant epitopes of low natural efficacy. However, theoretical models suggest that the antigenic evolution of influenza is best explained by postulating the existence of highly immunogenic epitopes of limited variability. Here we report the identification of such an epitope of limited variability in the head domain of the H1 haemagglutinin protein. We show that the epitope mediates immunity to historical influenza strains not previously seen by a cohort of young children. Furthermore, vaccinating mice with these epitope conformations can induce immunity to all the human H1N1 influenza strains that have circulated since 1918. The identification of epitopes of limited variability offers a mechanism by which a universal influenza vaccine can be created; these vaccines would also have the potential to protect against newly emerging influenza strains.

epidemiology↗

bioRxiv2017

The use of hyperimmune chicken reference sera is not appropriate for the validation of influenza pseudotype neutralization assays

Pseudotype particle neutralization (pp-NT) is a next-generation serological assay employed for the sensitive study of influenza antibody responses, especially haemagglutinin stalk-directed antibodies. However, to date a validation of this assay has not been performed, and this limits its use to primarily research laboratories. To identify possible serological standards to be used in optimization and validation of the pp-NT, we have evaluated the cross-reactivity of hyperimmune chicken reference antisera in this assay. Our findings show that the cross-reactivity detected by the pp-NT assay is only in part explained by phylogenetic relationships and protein homology between the HA subtypes analysed; further studies are necessary to understand the origin of the cross-reactivity detected, and reference standards with higher specificity should be evaluated or generated de novo for future use in pp-NT.

microbiology↗