For establishment of preerythrocytic vaccination model against mice malaria Plasmodium berghei, we tried to induce cellular immunity to CS protein of plasmodium berghei.
1.Cytotoxic T cell epitope, NDDSYIPSAEKI which is recognized in a context with H-2 K^d by CTL lines against CS protein of Plasmodium berghei was biochemically synthesized. This 12mer peptide and heat shock protein 70 were mixed and incubated for 1 hour ar 37ﾟC for making the hsp70-peptide.
2.BALB/c mice were immunized with 10mg (per mouse) of this hsp70-peptide complex twice at a week interval and spleens were removed and suspended cells were incubated with the peptide for five days in 5% CO_2,37ﾟC.Cytotoxic activity of the effector cells was assayd with ^<51>Cr labelled P815 target cells pulsed with the peptide.
3.By in vitro stimulation with the different dose, 1 x 10^<-4>,1 x 10^<-5>,1 x 10^<-6>,1 x 10^<-7>,1 x 10^<-8> mol of the peptide, optimal concentrations of the peptide were identified as 1 x 10^<-6> and 1 x 10^<-7> mol for induction of primary CTLs.
4.Incubation of spleen cells with the peptide in the presence of IL2 revealed no mounting effect of cytotoxic activity was observed, rather IL2 decreased the activity.
5.Since repeated stimulation of effector cells with the peptide apparently increased the cytolytic activity, establishment of long term cultured cell lines were on going now.