Figure 4.

i.ln. immunization elicits protective immunity against systemic and peripheral virus infection. (A) Groups of three C57BL/6 mice were immunized once with pEGFPL33A given i.m. (200 μg) or i.spl. (20 μg) or i.ln. (20 μg). Positive control mice received 500 pfu LCMV i.v. Ten days after immunization mice were challenged with 5 × 10⁴ pfu LCMV i.v., and 4 days later spleens were isolated and LCMV titers were determined. Symbols represent individual mice; one of two similar experiments is shown. (B) Groups of three C57BL/6 mice were immunized four times at 6-day intervals with pEFGPL33A DNA administered either i.m. (100 μg per immunization) or i.ln. (10 μg per immunization). Five days after the last immunization they were challenged with 5 × 10⁶ pfu Vacc-G2 i.p., and vaccinia titers in ovaries were assessed after a further 5 days. Symbols represent individual mice; one of two similar experiments is shown.