as there were no significant differences in incubation periods among the five groups ( lasat , nude , dh , hetero and balb/c ) inoculated with the same dilution , via the same route , it was concluded that cell-mediated immunity dependent on the thymus plays no significant role in host defence against the cjd agent , and the spleen , a critical site of agent replication , is apparently not an obligatory source from which infection spreads to the central nervous system .
C0020966
cell-mediated immunity
C0520990
host defence