The effect of exogenous interferon on the origin and course of virus infection has been studied by numerous investigators. Originally experiments were carried out on rabbits infected with vaccinia and herpes viruses. The first experiments were carried out by Isaacs and co-workers, who injected chick interferon intradermally into rabbits 24 h before infection with vaccinia virus with the result that the development of the cutaneous lesions was restricted . Much better results were obtained by using rabbit interferon in experiments of various types . The interferon was injected: a) on the day before infection; b) at the same time as the virus; c) on the day after infection. The intensity of the protective action of the interferon depended on the dose of vaccinia virus used. If 104–105 infective doses of vaccinia virus were used for infection complete protection was observed if the interferon was injected the day before the virus, but not if it was injected with or after the virus. Interferon gave complete protection when injected simultaneously with the virus provided that the infective dose of the virus was reduced by half. No protection was found if the interferon was injected after infection with the virus regardless of its dose. Rabbit interferon has been used for the treatment of vaccinial and herpetic keratitis . After infection via the scarified cornea interferon was injected subconjunctivally six times a day. In the case of infection by herpes virus, interferon had no therapeutic action despite its use for 4 days, but it was effective against vaccinial keratitis. Repetition of these experiments by Hirst and Finter (cited in ) revealed a well-marked therapeutic effect in herpetic keratitis, but only if partially purified preparations of homologous interferon were used.
KeywordsHerpes Zoster Chick Embryo Protective Action Vesicular Stomatitis Virus Human Interferon
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