FIG. 4.

IFN-γ production by splenocytes from infected mice. Splenocytes from mice infected for 13 days or 104 days with the different rBCG clones were challenged in vitro with PPD, and IFN-γ in cell supernatants was measured. Results show the mean and standard error for triplicate assays with splenocytes pooled from five mice per group. On day 13, IFN-γ production was significantly higher for splenocytes from mice infected with LAP-BCG. On day 104, the IFN-γ response was higher in mice that received control BCG. P values were <0.05 (single asterisks) and <0.001 (double asterisks).