New efficient intercellular spread mode of respiratory syncytial virus contributes to neutralization escape and persistence

There is no licensed vaccine or therapeutic antibody for respiratory syncytial virus (RSV). The induction of high-titer, potent neutralizing antibodies cannot completely inhibit breakthrough infection and enhanced respiratory disease (ERD), encouraging a focus on the relationship between virus intercellular spread and neutralizing antibodies. By blocking the known intercellular spread modes and with the aid of ultrahigh-resolution imaging, we observed a new efficient mode of intercellular spread in which RSV-infected cells directly transfer viral materials (including viral replication factories) to neighboring cells through protruding open-ended microfilament-rich intercellular nanotubes. The new mode is virion-independent and antibody-insensitive, beginning as early as 3 h post infection. Furthermore, replication-defective viral genomes (DVGs) might also utilize the new mode, facilitating the establishment of latent viral infections. Therefore, our data provide a new perspective on RSV cell-to-cell spread and might help to explain the immune escape and latent persistence of paramyxoviruses.