Alteration of Susceptibility of Embryonated Eggs to Newcastle Disease Virus by Escherichia coli and Endotoxin

Abstract

The susceptibility of chick embryos to Newcastle disease virus may be altered by infection with embryo-avirulent E. coli. Phases of enhanced susceptibility and of enhanced resistance may be obtained depending on the time of initiation of infection with E. coli. Similar effects of smaller magnitude are induced using small amounts of purified endotoxin in lieu of E. coli at appropriate times. This, and previous information (Jour. Exptl. Med. 112 315, 1960), indicates that chick embryos are capable of a response to endotoxin similar to that reported in mature animals which results in an altered susceptibility to bacterial and viral pathogens. The developing chick embryo should be a valuable tool in further study of these phenomena.