摘要：The potency of Japanese encephalitis (JE) vaccine is routinely tested by intracerebral challenge of immunized mice, but since natural infection is by a peripheral route the author was led to develop a subcutaneous challenge test, using the natural route. Suckling mice 8-10 days old were immunized twice intraperitoneally with 0.15 ml of different serial dilutions of vaccine on days 1 and 4. A challenge dose of JE virus equal to 5000 intracerebral LD50 for suckling mice was given on day 8, when the mice were not older than 19 days. The JaGAr 01 strain was used as the challenge virus, being more freshly isolated than the Nakayama strain usually employed in Japan and therefore less likely to have been modified by repeated mouse-brain passage. This new assay method should give a more accurate assessment of the effect of a vaccine which is intended to protect man from natural infection only and not from infection by an unnatural route. Full text Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (477K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References . 553 554 555 556 557
