Study of coronavirus OC43 infections has been limited because of the lack of sensitive cell culture systems and serologic assays. To improve this circumstance, we developed an indirect enzyme immunoassay (ETA) to detect serum antibody to OC43. Antigen (100 ng) prepared by polyethylene glycol precipitation provided optimal results without a postcoat procedure. Evaluation of intraplate variation indicated that a 22.5-fold increase in serum titer was significant. Sixteen of 18 (89%) paired serum

more »

... mples with previously identified, reproducible increases in the level of hemagglutination inhibition (HAI) antibody to OC43 also showed significant increases as detected by ETA. Specificity for the EIA was established with paired sera obtained from persons given influenza immunizations or experiencing a respiratory infection. No rises in antibody titers occurred among 33 persons with documented coronavirus 229E infection. EIA was then performed on each of 419 paired serum samples from ambulatory chronic obstructive pulmonary disease patients and healthy older adults, from asthmatic adults presenting for emergency room treatment, and from persons hospitalized with acute respiratory symptoms. Twenty-three antibody rises to OC43 were detected; only nine of these were