Rapid culture-amplified immunofluorescent test for the detection of human rhinoviruses in clinical samples: evidence of a common epitope in culture

Abstract

Ohio HeLa cells in multichamber slides were inoculated with nasal samples from patients presenting with common cold symptoms and incubated at 33 degrees C with gentle shaking for 48 hours. The cultures were fixed with cold acetone, and viral antigens were detected by immunofluorescence using an antirhinovirus type 2 (HRV-2) polyclonal serum. Of 158 samples, 58 (36.7%) and 57 (36%) were positive for HRV by virus isolation (confirmed by acid lability test) and by culture-amplified immunofluorescent (CAIF) test, respectively. The correlation between the two tests was highly significant (P = 0.0001). Nasal washings or nasal/throat swabs were equally suitable for detecting virus by isolation but not by CAIF. On the other hand, nasal washings were better than nasal/throat swabs for detecting HRV by CAIF. In an ELISA system, the polyclonal anti-HRV-2 serum recognized a rhinovirus antigen expressed in situ within 48 hr postinfection by all the 11 HRV serotypes investigated. However, 60 hr postinfection, the anti-HRV-2 serum recognized only homologous and closely related HRV antigens. These results suggest that a rhinovirus "common" antigen may be expressed some 48 hr after infection of Ohio HeLa cells with rhinoviruses. The CAIF test provides a sensitive, rapid and reliable procedure to detect wild-type rhinovirus infection as well as a clear alternative to detection by isolation.