Modulation of monocyte Mo2 surface antigen expression by exposure to respiratory syncytial virus

The Mo2 antibody recognizes a monocyte-specific cell surface antigen of unknown function. Upward modulation of Mo2 surface epitope density was demonstrated in response to 72-hr culture of monocytes with respiratory syncytial virus (RSV), but this was not seen after culture with phytohemagglutinin or other respiratory viruses. Monoclonal antibody probes for RSV proteins were used to demonstrate probable replication of RSV proteins in peripheral blood monocytes and pulmonary alveolar macrophages. These data provide possible clues to the biologic role of the Mo2 antigen.