Interferon in Rabbit Brain, Cerebrospinal Fluid and Serum Following Administration of Polyinosinic-Polycytidylic Acid

The present study was undertaken to compare interferon levels in rabbit brain, cerebrospinal fluid and serum following parenteral administration of a synthetic, double-stranded RNA, polyinosinic-polycytidylic acid, a potent inducer of interferon. Following intravenous administration of polyinosinic-polycytidylic acid the titers of interferon in the brain and cerebrospinal fluid were always a small fraction of those in the serum. Intrathecal administration of polyinosinic-polycytidylic acid significantly increased the later-appearing interferon in the cerebrospinal fluid but did not significantly affect the interferon titers in the brain. Local injection of polyinosinic-polycytidylic acid intracerebrally did give rise to more sustained levels of interferon in the brain. However, the highest levels of brain interferon were always far below the highest levels which could be achieved in the serum. Local production of interferon in the brain and its meninges was indicated by the finding that after intracerebral administration of polyinosinic-polycytidylic acid the levels of interferon in the brain and cerebrospinal fluid exceeded those in the serum.