Rhinoviruses replicate effectively at lower airway temperatures

Rhinoviruses are epidemiologically connected to the majority of acute asthm a exacerbations; however, their ability to infect and replicate in the lowe r airways is disputed. A frequent argument against this possibility involve s the temperature preference for rhinovirus replication, generally accepted to be 33 degrees C, the temperature of the nasal passages. However, this a rgument is based on studies with a single rhinovirus serotype. In this stud y, differences in temperature preferences were evaluated between several se rotypes and relative titers were determined than can be achieved at upper a :nd lower airway temperatures. Rhinovirus serotypes 1b, 2, 7, 9, 14, 16, 41 , and 70 were titrated in Ohio-HeLa cell cultures at either 33 degrees C or 37 degrees C. Possible selection by culture temperature was examined by co ntinuous culture at 33 degrees C and 37 degrees C for 2-4 passages and subs equent titration at both temperatures. Finally, nasal aspirate samples deri ved from patients with wild-type rhinoviral common colds were cultured at 3 3 degrees C and 37 degrees C and RT-PCR was used to assess rhinovirus repli cation at each temperature. The majority of the serotypes and wild-type vir uses replicated slightly better at 33 degrees C than at 37 degrees C. Howev er, titers achieved after one or more replicative cycles at 37 degrees C we re still high enough to initiate infection. Furthermore, in some instances equal or even better replication was observed at 37 degrees C. It is conclu ded that temperature preferences may vary between rhinoviruses and are not likely to be a prohibitive factor for infection of the lower airways. J. Me d. Virol. 58:100-104, 1999. (C) 1999 Wiley-Liss, Inc.