Development of a novel competitive ELISA to investigate exposure of
animals to SARS-CoV-2
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the
COVID19-causing virus, is a zoonotic pathogen. There is concern that it
may spillover into wildlife species which may then serve as reservoirs
for future infection of humans, domestic animals, or other wildlife
species. Furthermore, impacts of the virus on potentially susceptible
wildlife species are currently unknown. There is, therefore, an urgent
need to develop a single test that could be used for the
serosurveillance of multiple wildlife species for exposure to
SARS-CoV-2. While serological tests to detect antibodies in SARS-CoV-2
infected and/or exposed human patients have been developed, few assays
have the capacity to detect antibodies in a wide variety of species.
Here, we describe the development of a competitive enzyme-linked
immunosorbent assay (cELISA) to detect SARS-CoV-2 antibodies in animals
for which species-specific reagents are not available. This cELISA was
developed to detect SARS-CoV-2 spike 1 (S1), spike 2 (S2) and
nucleocapsid (N) specific antibodies and was validated using sera from
experimentally infected hamsters. We further validated our cELISA by
comparing it with results obtained from the surrogate virus
neutralization test (cPASS, GenScript) and indirect ELISA using
anti-hamster horse radish peroxidase (HRP) conjugated reagents. This
cELISA will have broad applications in screening potential animal
reservoirs for SARS-CoV-2, and uses multiple targets, including more
conserved structural proteins which are subjected to less selective
immunological pressure. These would allow detection of exposure to
variants missed by conventional assays that target antibodies against
the viral receptor binding domain. This assay will be a valuable tool
which can be implemented in surveillance programs investigating evidence
of exposure to SARS-CoV-2 in multiple domestic, captive, or wild animal
species, and in studies investigating impacts of SARS-CoV-2 on wildlife
populations.