Serological and transcriptomic response of African fruit bats to immune challenge with recombinant vaccines expressing Ebola or Nipah virus antigens.

Abstract

Bats are hosts to diverse zoonotic viruses which can cause high case fatality rates in humans. Since detecting viruses in bats is difficult, antibodies are often used for surveillance, though their significance remains unclear in the absence of in vivo immunological studies. To address this knowledge gap, we measured antibody production and gene expression in bats following injection with vaccines encoding either a Nipah virus G glycoprotein or an Ebola virus GP glycoprotein. We selected two African bat species with overlapping ranges, Eidolon helvum (confirmed reservoir of henipaviruses) and Epomophorus gambianus (putative reservoir of filoviruses). Using a Luminex-based multiplex microsphere immunoassay and a pseudotype virus neutralization assay, we observed an increase in antibodies against the Nipah glycoprotein in most bats that received the Nipah vaccine. In contrast, we could only detect anti-Ebola glycoprotein antibodies in one bat species, Ep. gambianus, in response to the Ebola vaccine. Transcriptomic analysis in Ei. helvum revealed that genes involved in ISGylation and T-cell differentiation pathways were differentially expressed in response to the Ebola, but not the Nipah, vaccine. These results demonstrate species-specific differences in responses to antigen exposure, offering insights into bat adaptive immune systems and providing calibration for serological data from wild bats.