FIG. 7.

Results of an animal experiment in which groups of four pigs were infected with the RNase-negative CSFV V-H297K (group 1), the dimerization-negative mutant V-C171d (group 2), or wt Alfort/Tübingen recovered from the infectious cDNA clone (group 3). Clinical scores, according to the system published by Mittelholzer et al. (38), are given as mean values for each group (A). Also shown are the average body temperature (B), the mean values of leukocyte counts (C), the percentage of virus-positive cells in complete blood samples (as described in reference 57) (D), the amount of type I IFN in plasma samples compared to an IFN-α standard (1 ng per well) (E), and the titers of virus-neutralizing serum antibodies of the pigs, given as the maximal reciprocal dilution of the sera that is able to neutralize 100 50% tissue culture infective doses of CSFV Alfort/Tübingen (F). Standard deviations are indicated in panels A, D, and E.