Protection of athymic (Nu/Nu) BALB/c mice against Plasmodium berghei by splenocytes from normal (Nu/+) BALB/c mice.

Athymic B A L B / c ( N u / N u ) mice died at 7-13 days after inoculation ( D A I ) of P lasmodium berghei NK65 , whereas their heterozygous ( N u / + ) l i t termates died at 7-8 D A I . N u d e ( N u / N u ) mice , reconsti tuted w i th 2 x 10 7 splenocytes f r o m unin­ fected heterozygous ( N u / + ) l i t termates at 20 days before parasite inoculation ( D B I ) , died about 2 days earl ier than control nude mice ; nude mice reconsti tuted at 10 or 2 D B I l ived 2 to 4 days longer than control nudes; and nude mice re­ constituted 2 D A I l ived even longer and some survived. These findings indicate that P . berghei N K 6 5 induces at least t w o T-cell dependent immune phenomena, one suppressive and the other s t imulatory. Reconsti tut ion o f nude mice w i th T-cells f r o m B A L B / c ( N u / + ) mice appeared to reduce or bypass suppressive T-cell activities wh ich a l lowed the fo rmat ion of a protect ive immune response b y some of the nude mice .