In a similar series of experiments, we also examined the effect of the dose (106 versus 108 pfu) of live TGEV-A administered oronasally to 11day-old TGEV seronegative pigs, on primary and memory ASC responses in the MLN and BLN (Saifet al., 1994b; Saif, 1996; VanCott et al., 1993) .