摘要：
The authors attempted to propagate MM murine virus serially in embryonated eggs. In these expts. 8- to 9-day-old embryo-nated eggs were inoculated by the allantoic route with 0. 1ml. of 10% MM viral mouse brain suspension or with 0.1 ml. of chick embryo tissue culture virus. Following incubation at 35 [degree]C for 4-5 days, further passages were made by transfer of undiluted allantoic fluid or of 10% embryonic brain suspension to new eggs. The presence of virus was tested at frequent intervals by titrating the transfer fluids in mice intra-cerebrally and intraperitoneally. The results demonstrate the extreme irregularity in the ability of MM virus, harvested from different mouse brain passages, to propagate in embryonated eggs. In 2 expts. serial transmission could be maintained over 5 or 6 passages;in 3 other expts. transfers did not succeed beyond the first passage. They made attempts also, to adapt MM murine virus to young chicks. Young chicks were injd. intracerebrally and intraperit. with murine virus harvested from the brains of mice paralyzed by MM mouse passage virus. Of the injd. chicks, -a number were kept for a period of 4 weeks to observe for symptoms, and the remaining ones were sacrificed at 24, 48 and 72 hrs. to transfer intracerebrally in "blind passage" a suspension prepd. from their brains or cords to new chicks. 4 serial chick to chick passages were thus maintained. The animals varied in age between 1 and 7 days and the chicks came from a tested hatchery to eliminate Salmonella pullorum infection. Among a total of 40 chicks inoculated with MM viral mouse brain, not a single chick was observed with paralysis;however, 3 sera collected from symptomless chicks contained large amts. of virucidal antibodies (10,000 to 100,000 paralytic doses neutralized). No paralysis was observed in "blind passage" chicks and their sera showed no antibodies. Allantoic fluid with a virus content of 10-6, transferred from the 4th egg passage, produced paralysis in 1 of
欢迎来到三峡大学图书馆！
