2.6. IFN-γ ELISPOT assay
PBMCwere thawed,washed and resuspended to a concentration
of 6–8×106 cells per ml in RPMI-1640 supplemented
with 5% heat-inactivated AB serum (Valley Biomedical,
Winchester, USA), 2mM l-glutamine, 100 U/ml penicillin
and 100 g/ml streptomycin. Cells were cultured in 24-well