CTL specificity of wt and LCMV variants used.

LCMV variants GPV1 or GPV, or the parental wt LCMV ARM virus, were inoculated (1×105 PFU i.p.) into C57Bl/6 (H-2b) or Balb/cdj (H-2d) mice. Seven days later lymphocytes were obtained from spleens and used in a cytotoxic 51Cr-release assay at an effector to target ratio of 50∶1 as described in Materials and Methods. The generation, selection, sequencing and specificity of GPV1 and GPV have been published [26], [27]. Target cells H-2b (MC-57) and H-2d (Balb Cl 7) as described [25], [26], [50] were infected with LCMV ARM or VV constructs expressing the whole wt LCMV nucleoprotein (NP), whole LCMV GP, or just the N-terminal component of GP containing the GP-33 CTL epitope but not the GP-276 CTL epitope [50]. Numbers represent the mean of triplicate samples ± 1 SD from four mice per experimental group.