Indirect ELISAs Based on Nipah and Langya Virus Proteins for Detecting Antibodies in Animals

Nipah virus (NiV) and Langya virus (LayV) are emerging zoonotic henipaviruses with serious public health risks. However, no vaccine or drug is available for either disease. To address the persistent threats posed by NiV and LayV, we preliminarily developed indirect ELISAs based on truncated fusion glycoprotein (F protein) and attachment glycoprotein (G protein) expressed in a mammalian expression system. We validated these assays using immunized BALB/c mice (for both NiV and LayV), immunized Syrian golden hamsters (for NiV), and goats and a dog that were naturally infected (for LayV). Specificity was assessed using negative sera from mice, ferrets, African green monkeys, hamsters and swine. The ELISAs demonstrated high sensitivity (1:64,000) for both viruses in immunized BALB/c mice, high specificity (approximately 95% in mice and 100% in ferrets, African green monkeys, hamsters and swine) and strong concordance with commercial NiV ELISA kits (>93%). The NiV ELISAs were further validated using immunized Syrian golden hamsters, which had sensitivities of 1:51,200 (F protein-based) and 1:6,400 (G protein-based). The LayV ELISAs successfully detected antibodies in the sera of goats and a dog naturally infected with LayV. These preliminary indirect ELISAs serve as proof-of-concept tools and may be valuable for vaccine and therapeutic development, serological surveillance studies and future diagnostic platform development.