Interferon inducers were used against vaccinial
encephalitis to study the target-organ treatment of neurotropic disease and to correlate
interferon levels and the
antiviral state following such treatment. A 45-mug amount of
statolon, 30 mug of polyribinosinic-polyribocytidylic
acid complex (
poly I.
poly C), or 0.0154 HA unit of Sendai virus given intracerebrally protected 100% of mice challenged the next day with 1,000 median lethal doses (LD(50)) of vaccinia virus. Significant protection against 1,000 LD(50) of vaccinia virus persisted for 1, 4, or 3 weeks after
poly I.
poly C,
statolon, or Sendai virus (154 HA units), respectively. These doses of
poly I.
poly C and
statolon were also used to study postinfection treatment. Mice challenged with 1, 10, 100, or 1,000 LD(50) were treated intracerebrally with
poly I.
poly C or
statolon 24 or 48 hr later. Significant increases in survival time were seen in mice challenged with 1 to 100 LD(50) of vaccinia virus and treated 24 hr later. At challenges of 10 or 100 LD(50),
statolon was more effective than
poly I.
poly C in increasing survival times. When treatment was delayed until 48 hr after
infection, significant increases in survival time occurred only when the challenges were in the range of 1 to 10 LD(50), with
poly I.
poly C and
statolon being equally effective.
Interferon was measured by Finter's
dye-uptake method, with L-929 cells and Semliki Forest virus.
Poly I.
poly C,
statolon, or Sendai virus, given intracerebrally to mice, produced serum
interferon peaks of 5,120 units/ml at 2 hr, 2,560 units/ml at 12 hr, or 320 units/ml at 18 hr, respectively. Corresponding brain
interferon peaks were 640 units/g at 2 hr, 640 units/g at 4 to 24 hr, and 960 units/g at 72 hr.