Figure 8. Augmentation of CTL differentiation in vivo by the treatment with Ksp37 DNA was demonstrated. C57BL/six mice were challenged with killed H37Ra antigen (1,000 µg/mouse) in vivo (i.p.) and then treated with Ksp37 DNA (100 µg/mouse, six times) i.m. Twenty-one days after challenge of killed TB antigen, and PEC (peritoneal exudate cells) from these mice were harvested. CTL activity againt TB antigen (HSP65 antigen) was assessed by using ⁵¹Cr EL-4 which had been transfected with HSP65 DNA.