Neutralizing Antibodies with Neurotropic Factor Treatment Maintain Neurodevelopmental Gene Expression Upon Exposure to Human Cytomegalovirus

Abstract

Human cytomegalovirus (HCMV) is a beta herpesvirus that causes severe congenital birth defects including microcephaly, vision loss, and hearing loss. Infection of cerebral organoids with HCMV causes significant downregulation of genes involved in critical neurodevelopmental pathways. The precise features of the infection causing this dysregulation remain unknown. Entry of HCMV into human cells is determined by the composition of glycoproteins in viral particles, which is influenced by the source of the virus. This includes a trimer complex and a pentamer complex with the latter enriched from replication in epithelial cells. To begin dissecting which features contribute to neuronal pathogenesis, we evaluated infection using virus from different sources along with the distribution of cellular entry receptors on cells in cerebral organoids. We observed significant increases in the number of viral genomes, viral spread and penetrance, and multinucleated syncytia in neural tissues infected with HCMV propagated in epithelial cells compared to fibroblasts. To determine if this was related to entry receptor distribution, we measured expressions of cellular entry receptors and observed similar distributions of all receptors on cells obtained from organoids indicating that source of virus is likely the key determinant. Next, we asked whether we could limit pathogenesis using neutralization antibodies. We found that pre-treatment with antibodies against viral glycoprotein B (gB) and gH successfully decreased viral genome levels, viral gene expression, and virus-induced syncytia. In contrast, targeting specific cellular entry receptors failed to limit infection. Using an antibody against gB, we also observed partial protection of developmental gene expression that was further improved by the addition of brain derived neurotropic factor (BDNF). These studies indicate that source of HCMV is a key determinant of neuronal pathogenesis that can be limited by neutralization antibodies and neurotropic factors.