Biology subjects

Truscon, R.

Publications and source records attributed to Truscon, R..

3 recordsLinked to original sources

bioRxiv2023

A rapid and flexible microneutralization assay for serological assessment of influenza viruses

BackgroundSerological responses from influenza vaccination or infection are typically measured by Hemagglutinin Inhibition (HAI) or Microneutralization (MN). Both methods are limited in feasibility, standardization, and generalizability. We describe a luciferase MN (LMN) assay that combines the advantages of the conventional MN assay with the ease of the HAI assay MethodsSera were obtained from the HIVE study. Plasmid transfection was used to generate recombinant influenza viruses expressing the hemagglutinin and neuraminidase of test strains, all other viral proteins from A/WSN33, and a NanoLuc reporter. Serum neutralization of luciferase-expressing targets was quantified as a reduction in Relative Light Unit (RLU) emission from infected cells. Neutralization titers were measured for cell- and egg-adapted versions of A/H3N2/Hong Kong/4801/2014 and A/H3N2/Singapore/INFIMH-16-0019/2016 and compared to HAI titers against egg-grown antigens. Results333 sera were collected from 259 participants between May 2016 and July 2018. Sampled participants ranged from 7 to 68 years of age and >80% were vaccinated against influenza. HAI and LMN titers were correlated for A/H3N2/Hong Kong/4801/2014 ({rho}=0.45, p[≤]0.01) and A/H3N2/Singapore/INFIMH-16-0019/2016 ({rho}=0.75, p[≤]0.01). LMN titers were lower for cell strains compared to egg strains (A/H3N2/Hong Kong/4801/2014 mean log2 fold change = -2.66, p[≤]0.01 and A/H3N2/Singapore/INFIMH-16-0019/2016 mean log2 fold change= -3.15, p[≤]0.01). ConclusionsThe LMN assay was feasible using limited sample volumes and was able to differentiate small antigenic differences, specifically between egg-adapted and cell-derived strains. The correspondence of these results with the commonly-used HAI confirms the potential utility of this assay for high-throughput studies of correlates of protection and vaccine response.

microbiology↗

bioRxiv2018

Evaluation of correlates of protection against influenza A(H3N2) and A(H1N1)pdm09 infection: Applications to the hospitalized patient population.

BackgroundInfluenza vaccines are important for prevention of influenza-associated hospitalization. Assessments of serologic correlates of protection can support interpretation of influenza vaccine effectiveness evaluations in hospitalized populations.\n\nMethodsSerum specimens collected at admission from adults hospitalized for treatment of acute respiratory illnesses during two influenza seasons were tested in hemagglutination-inhibition (HAI) and neuraminidase-inhibition (NAI) assays. We evaluated the suitability of these specimens as proxies for pre-infection immune status, and measured associations between antibody titers and influenza vaccination and infection\n\nResultsSpecimens were collected within 3 days of illness onset from 65% of participants; geometric mean titers (GMTs) did not vary by day of collection. In both seasons, vaccinated participants had higher HAI and NAI GMTs than unvaccinated participants. HAI titers against the 2014-2015 A(H3N2) vaccine strain did not correlate with protection from infection with antigenically-drifted A(H3N2) viruses that circulated that season. In contrast, higher HAI titers against the A(H1N1)pdm09 vaccine strain were associated with reduced odds of A(H1N1)pdm09 infection in 2015-2016.\n\nConclusionsSerum collected after hospital admission can be used to assess correlates of protection against influenza infection. Broader implementation of similar studies would provide an opportunity to understand the successes and shortcomings of current influenza vaccines.

epidemiology↗

bioRxiv2016

Vaccination has minimal impact on the intrahost diversity of H3N2 influenza viruses

While influenza virus diversity and antigenic drift have been well characterized on a global scale, the factors that influence the virus rapid evolution within and between human hosts are less clear. Given the modest effectiveness of seasonal vaccination, vaccine-induced antibody responses could serve as a potent selective pressure for novel influenza variants at the individual or community level. We used next generation sequencing of patient-derived viruses from a randomized, placebo-controlled trial of vaccine efficacy to characterize the diversity of influenza A virus and to define the impact of vaccine-induced immunity on within-host populations. Importantly, this study design allowed us to isolate the impact of vaccination while still studying natural infection. We used pre-season hemagglutination inhibition and neuraminidase inhibition titers to quantify vaccine-induced immunity directly and to assess its impact on intrahost populations. We identified 166 cases of H3N2 influenza over 3 seasons and 5119 person-years. We obtained whole genome sequence data for 119 samples and used a stringent and empirically validated analysis pipeline to identify intrahost single nucleotide variants at [≥]1% frequency. Phylogenetic analysis of consensus hemagglutinin and neuraminidase sequences showed no stratification by pre-season HAI and NAI titer, respectively. In our study population, we found that the vast majority of intrahost single nucleotide variants were rare and that very few were found in more than one individual. Most samples had fewer than 15 single nucleotide variants across the entire genome, and the level of diversity did not significantly vary with day of sampling, vaccination status, or pre-season antibody titer. Contrary to what has been suggested in experimental systems, our data indicate that seasonal influenza vaccination has little impact on intrahost diversity in natural infection and that vaccine-induced immunity may be only a minor contributor to antigenic drift at local scales.

microbiology↗