Biology subjects

Rutten, V.

Publications and source records attributed to Rutten, V..

3 recordsLinked to original sources

bioRxiv2023

Low gH/gL (sub)species-specific antibody levels indicate elephants at risk of fatal elephant endotheliotropic herpesvirus hemorrhagic disease

Elephant endotheliotropic herpesviruses (EEHVs), of which seven species and multiple subspecies are currently distinguished, naturally infect either Asian (Elephas maximus) or African elephants (Loxodonta species). While all adult elephants are latently infected with at least one EEHV (sub)species, EEHV infections in young elephants may lead to acute, fatal hemorrhagic disease (EEHV-HD). The disease is primarily observed in calves with low to non-detectable EEHV-specific antibodies, suggesting it is the result of an uncontrolled primary infection. Yet, young elephants showing high antibody levels in serological assays based on EEHV(1A) gB, which detect antibodies against multiple EEHV (sub)species, are not necessarily protected against EEHV-HD. To better determine which animals are at risk of EEHV-HD, we developed gB and gH/gL ELISAs for all Asian elephant EEHV (sub)species and assessed their specificity using 396 sera from 164 Asian elephants kept in Europeans zoos. Antibody levels measured against gB of different EEHV (sub)species correlated strongly with one another, indicating gB-specific antibodies are highly cross-reactive. In contrast, antibody responses towards gH/gL of different EEHV (sub)species were far less correlated and could be used to distinguish between infections with different (sub)species. Subsequently, antibody responses in sera of 23 EEHV-HD fatalities were analyzed. Whereas high antibody levels against gB could be detected in sera of multiple EEHV-HD fatalities, all fatalities had low antibody levels against gH/gL of the EEHV (sub)species they succumbed to. Overall, our data indicate that (sub)species-specific gH/gL ELISAs may be used to identify animals at risk of developing EEHV-HD upon infection with a particular EEHV (sub)species.

microbiology↗

bioRxiv2020

Elephant endotheliotropic herpesvirus is omnipresent in elephants in European zoos and an Asian elephant range country

Elephant endotheliotropic herpesviruses (EEHVs) are a group of evolutionary divergent herpesviruses that may cause acute, often lethal, hemorrhagic disease (EEHV-HD) in young elephants. Although EEHV was first discovered over 20 years ago, its prevalence in different elephant populations is still largely unknown, partially due to the lack of readily available, sensitive serological assays. In order to improve diagnostic tools for the detection of EEHV infections and to obtain insight in its spread among elephants, we developed novel ELISAs focusing on EEHV1A gB and gH/gL as antigens. Performance of the ELISAs was assessed using sera taken from 41 European zoo elephants and 69 semi-captive elephants from Laos, one of the Asian elephant range countries. Sera from all (sub)adult animals tested ([≥]5 years of age) showed high reactivity with both gB and gH/gL, whereas reactivity towards the antigens was generally lower for sera of juvenile animals (1 > 5 years). Only one (juvenile) animal, which was sampled directly after succumbing to EEHV-HD, was found to be seronegative for EEHV. The two other EEHV-HD cases tested showed low antibody levels, suggesting that all three cases died upon a primary EEHV infection. Direct comparison with another EEHV-specific ELISA previously used in two large serosurveys, showed that EEHV prevalence was underestimated before, likely due to aberrant folding of the antigen used. In conclusion, our study suggests that essentially all (semi-)captive (sub)adult elephants in European zoos and in Laos carry EEHV, and that young elephants with low antibody levels are at risk of dying from EEHV-HD. ImportanceOver the last 30 years, nearly 20% of all Asian elephants born in Western zoos succumbed to acute hemorrhagic disease caused by elephant endotheliotropic herpesvirus (EEHV-HD). Yet, the prevalence of EEHV in captive and wild elephant populations is still largely unknown, mainly due to the lack of readily available, sensitive serological assays. For this study two highly sensitive EEHV-specific ELISAs were developed. Using these assays, it was shown that nearly all elephants tested were seropositive for EEHV, with highest antibody levels detected in (sub)adult elephants. In contrast, antibody levels in EEHV-HD cases were very low or non-detectable. Lack of antibodies may thus be a risk factor for developing severe disease. As the novel ELISAs are low-tech in nature, these assays may easily be disseminated to local laboratories in zoos and elephant range countries in order to determine EEHV serostatus of individual animals or complete herds and (wild) populations.

microbiology↗

bioRxiv2020

A bright and high-performance genetically encoded Ca2+ indicator based on mNeonGreen fluorescent protein

Genetically encodable calcium ion (Ca2+) indicators (GECIs) based on green fluorescent proteins (GFP) are powerful tools for imaging of cell signaling and neural activity in model organisms. Following almost two decades of steady improvements in the Aequorea victoria GFP (avGFP)-based GCaMP series of GECIs, the performance of the most recent generation (i.e., GCaMP7) may have reached its practical limit due to the inherent properties of GFP. In an effort to sustain the steady progression towards ever-improved GECIs, we undertook the development of a new GECI based on the bright monomeric GFP, mNeonGreen (mNG). The resulting indicator, mNG-GECO1, is 60% brighter than GCaMP6s in vitro and provides comparable performance as demonstrated by imaging Ca2+ dynamics in cultured cells, primary neurons, and in vivo in larval zebrafish. These results suggest that mNG-GECO1 is a promising next-generation GECI that could inherit the mantle of GCaMP and allow the steady improvement of GECIs to continue for generations to come.

molecular biology↗