Figure 2.

Viral RNA is detectable in the lungs of RV1B-treated mice. (A) Female C57BL/6 mice were inoculated with RV1B by intranasal instillation and lungs were examined by RT-PCR for viral RNA 1 day postinoculation. Mice were also exposed to ultraviolet (UV)-irradiated replication-deficient RV1B or RV39, a major group virus. As a positive control, HeLa cells were infected for 1 hour with RV1B at a multiplicity of infection of 10. RNA was extracted 16 hours postexposure and analyzed for viral RNA. Blots shown are typical of three separate experiments. GAPDH = glyceraldehyde-3-phosphate dehydrogenase. (B and C) Lungs of RV1B-inoculated mice were examined for positive-strand (B) and negative-strand (replicative) (C) rhinovirus (RV) RNA by quantitative PCR. Although positive-strand viral RNA decreased steadily after inoculation, viral RNA was detected up to 7 days postinoculation. There was a small but significant increase in positive-strand viral RNA copy number between the 12- and 18-hour time points (P = 0.043, one-way analysis of variance). We also detected a modest amount of negative-strand viral RNA, consistent with viral replication (n = 4–6, geometric mean ± SEM). (D) Positive-strand viral RNA was detected in the nasal washes of RV1B-inoculated mice up to 3 days after exposure (n = 3, geometric mean ± SEM). (E and F) One day postexposure, lungs from sham-inoculated (E) or RV1B-inoculated (F) mice were formalin-fixed and probed with purified RV1B antiserum. Specific staining for RV1B was noted in some but not all central airways. Scale bars: 20 μm. (G–I) Supernatants from homogenized mouse lungs that were sham inoculated (G), inoculated with RV1B (H), or inoculated with UV-irradiated RV1B (I) were overlaid onto confluent HeLa cell monolayers and examined for cytopathic effect (arrowheads). Images shown are typical of three separate experiments (original magnification, ×100).