Abolition of passive immunity to bacterial infections by iron.

COMPARATIVELY little is known of the mechanisms of non-specific resistance to bacterial infection, although it is clear that many different factors are involved1. Experimentally, it is difficult to assess the importance of any one factor in the tissue itself because the interaction between parasite and host is a dynamic process which is not only complicated but subject to rapid change. Individual factors can sometimes be investigated in isolation in vitro, but this technique has the obvious disadvantage that the effect observed may have no real relevance to the situation in vivo. These difficulties may largely disappear if circumstances arise where a single factor can be seen to operate in a similar way in both situations.