At the 9th day after BCG-injection, SMA strain mice showed the marked reduction of LD
50 for endotoxin from E. coli 0-111 as compared with control mice.
On the contrary, the BCG-injected mice showed two to three fold increase of LD
50 for the PR 8 strain of influenza A virus.
This resistance promoting effect was shared with not only living BCG cells but also heat-killed BCG cells, but not with BCG-filtrate.
The effect was most effectively exhibited when BCG was inoculated intravenously, intermediately when intraperitoneally and least when subcutaneously. The inocuation by subcutaneous route was almost ineffective.
The effect was exhibited from about the 6th day after BCG-inoculation, reached the peak at the 10th to 12th day, and continued even after 30 days.
The effect of BCG inoculation on the intranasal infection of PR 8 was not exhibited.
There were no significant differences of LD
50, the degree of consolidation and the H. A titre of the lungs of dead mice, between BCG-inoculated and control mice.
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