Fig. 2.

Viral titers and viral RNA burdens in the brains of HCoV-OC43_NV-infected mice. Wild type and RAG1^−/− C57BL/6 mice were infected intranasally with 30 LD₅₀ HCoV-OC43_NV. (A and B) Whole brains were isolated at the indicated time points and titers of infectious virus and virus RNA burden were determined as described in Materials and methods. Titers from 3 representative mice are shown for each time point demonstrating correlation between recovery of infectious virus and viral RNA burden. (C) HCoV-OC43 RNA titers increase until day 7 p.i. then decline by day 9. Whole RNA was isolated from the indicated tissue and assayed for virus burden with real-time RT-PCR. Data in panel C are expressed as mean ± SEM for 4–6 mice per time point. Note the different scales in “Brain” and “Spinal Cord” versus “Lung” and “Intestine.” (*Indicates P < 0.05).