Efficient generation of vesicular stomatitis virus (VSV)-pseudotypes bearing morbilliviral glycoproteins and their use in quantifying virus neutralising antibodies

Nicola Logan,Elizabeth Mcmonagle,Angharad A Drew,Emi Takahashi,Michael Mcdonald,Michael D Baron,Martin Gilbert,Sarah Cleaveland,Daniel T Haydon,Margaret J Hosie,Brian J Willett

doi:10.1016/j.vaccine.2015.12.006

Abstract

Morbillivirus neutralising antibodies are traditionally measured using either plaque reduction neutralisation tests (PRNTs) or live virus microneutralisation tests (micro-NTs). While both test formats provide a reliable assessment of the strength and specificity of the humoral response, they are restricted by the limited number of viral strains that can be studied and often present significant biological safety concerns to the operator. In this study, we describe the adaptation of a replication-defective vesicular stomatitis virus (VSVΔG) based pseudotyping system for the measurement of morbillivirus neutralising antibodies. By expressing the haemagglutinin (H) and fusion (F) proteins of canine distemper virus (CDV) on VSVΔG pseudotypes bearing a luciferase marker gene, neutralising antibody titres could be measured rapidly and with high sensitivity. Further, by exchanging the glycoprotein expression construct, responses against distinct viral strains or species may be measured. Using this technique, we demonstrate cross neutralisation between CDV and peste des petits ruminants virus (PPRV). As an example of the value of the technique, we demonstrate that UK dogs vary in the breadth of immunity induced by CDV vaccination; in some dogs the neutralising response is CDV-specific while, in others, the neutralising response extends to the ruminant morbillivirus PPRV. This technique will facilitate a comprehensive comparison of cross-neutralisation to be conducted across the morbilliviruses.

Highlights

The aim of the study was to develop an assay that was rapid, sensitive and which enabled the analysis of neutralising responses against field strains of virus without a requirement for virus adaptation to Vero cell culture
One of the primary concerns with adapting viruses to cell culture is that the cell-culture adapted viruses no longer reflect the neutralisation sensitivity of field strains of the virus
Field strains of virus are generally isolated onto cells expressing the cognate SLAM molecule, while cell culture-adapted strains of virus are able to replicate in SLAM-negative cell lines such as Vero

Summary

Introduction

Many of the existing experimental systems for measuring neutralising antibodies to morbilliviruses utilise cell culture adapted strains of virus. The cell-culture adapted strains of measles virus (MeV) such as Edmonston and Hallé attach to target cells by binding to the complement regulatory protein CD46 [7,8]. While phylogenetically all morbilliviruses are closely related, with each viral species forming a single serotype [19,20], genotype-specific neutralising antibodies against MeV have been revealed by pre-absorbing sera from naturally infected individuals with cells expressing the haemagglutinin of a vaccine strain of virus [21]

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