Serum immunoglobulin G antibody subclass response to respiratory syncytial virus F and G glycoproteins after first, second, and third infections.

Serum samples from 31 children who experienced two or three infections with respiratory syncytial virus (RSV) in the first four years of life were tested in an enzyme-linked immunosorbent assay to examine the immunoglobulin G (IgG) subclass responses to the RSV F and G surface glycoproteins associated with primary infection and reinfection. We sought to determine whether the greater degree of glycosylation of the G glycoprotein was reflected in an IgG subclass immune response more like that to a polysaccharide antigen than to a protein antigen. We found that the IgG1/IgG2 ratio of postinfection antibody titers to F was fourfold higher than that to the G glycoprotein after RSV infections 1, 2, and 3. The IgG2 response to the heavily glycosylated G glycoprotein differed from that to a polysaccharide antigen in that the IgG1/IgG2 ratio remained constant with age, whereas the response to a polysaccharide antigen decreased as the IgG2 response increased with age. We also noted that antibody responses to both surface glycoproteins in the IgG1 and IgG2 subclasses reached their maximum levels after RSV infection 2

Development of Electrochemiluminescent Serology Assays to Measure the Humoral Response to Antigens of Respiratory Syncytial Virus

Sensitive and precise serology assays are needed to measure the humoral response to antigens of respiratory syncytial virus (RSV) following natural infection or vaccination. We developed and evaluated a collection of electrochemiluminescent (ECL) serology assays using four RSV antigens (F, N, Ga and Gb). To assess the merits of ECL technology, the four ECL serology assays were evaluated using a well-characterized gold standard panel of acute and convalescent serum samples from fifty-nine RSV-positive and thirty RSV-negative elderly subjects (≥65 years old). The combined results from the four ECL assays demonstrated good concordance to the gold standard diagnosis, reaching 95% diagnostic sensitivity and 100% diagnostic specificity. Additionally, a combination of ECL assays provided higher diagnostic sensitivity than a commercially available diagnostic ELISA or cell-based microneutralization assay. In summary, these data demonstrate the advantages of using ECL-based serology assays and highlight their use as a sensitive diagnostic approach to detect recent RSV infection in an elderly population