Circulating Antibody-Secreting Cells during Acute Respiratory Syncytial Virus Infection in Adults

Background. The specificity and duration of circulating human antibody-secreting cells (ASCs) after vaccination have been well described, but characteristics of ASCs during acute respiratory infections have not been well studied. Methods. Circulating antigen-specific ASCs were measured at 3 time points (enrollment, days 10-16, and days 22-45) in 40 adults during respiratory syncytial virus (RSV) infection. Results. Of the 40 patients, 36 (90%) had detectable circulating RSV F protein-specific ASCs within 11 days after illness onset. The magnitude of the RSV-specific ASCs was 1-1500 spots per 10(6) peripheral blood mononuclear cells (mean frequency [+/- standard deviation], 200 +/- 256 spots per 10(6) peripheral blood mononuclear cells). ASCs were detected on day 8-16 and day 22-45 after symptom onset in 78% and 48% of subjects, respectively. Subjects shedding virus for >10 days were more likely to have a positive response to ASC enzyme-linked immunospot assay at the late time point than those shedding for <= 10 days (8 of 12 subjects vs 2 of 11 subjects; P = .02). Conclusions. The kinetics of ASC circulation during acute mucosal viral infections was more prolonged than that we had observed after a single intramuscular injection with inactivated influenza vaccine in a study reported elsewhere. The association between the duration of virus shedding and the persistence of detectable viral-specific ASCs suggests that ongoing antigen persistence induces a prolonged temporal pattern of ASC generation.