The Secreted G Protein of Human Respiratory Syncytial Virus Antagonizes Antibody-Mediated Restriction of Replication Involving Macrophages and Complement

The respiratory syncytial virus (RSV) G and F glycoproteins are the neutralization antigens, and G also is expressed in a soluble form (sG). Previously, sG was demonstrated to reduce the efficiency of RSV antibody-mediated neutralization by serving as an antigen decoy and to inhibit the antibody-mediated antiviral effects of Fc receptor-bearing leukocytes. The present study demonstrated that effective antibody-mediated restriction in vivo, and the evasion of this restriction by sG, involves pulmonary macrophages and complement, but not neutrophils.