ICAM-1 deficiency protects against weight loss after viral infection without changing viral clearance. Wild-type and ICAM-1–null mice were inoculated with SeV (5,000 EID₅₀) and analyzed as follows. (a) Body weights relative to initial values were determined as mean ± SEM of eight mice. *Significant increase compared with the wild-type cohort. (b) Lungs were subjected to Western blotting against anti-SeV Ab, and bands corresponding to SeV nucleocapsid protein (NP) and the Sp1 control were quantified by densitometry as mean ± SEM of three mice. (c and d) Lungs were also assayed for SeV plaque-forming units (c) and SeV copy number (d). Values for viral plaque-forming units and viral RNA copy number represent mean ± SEM for 1 g of lung tissue and 100 ng of total lung RNA, respectively (three mice/genotype). Viral RNA copy number was determined by real-time RT-PCR for SeV nucleocapsid protein and corrected for GAPDH control. For a–d, values obtained from +/+ and –/– cohorts inoculated with PBS or UV-inactivated SeV were no different from preinoculation values (data not shown).