INCREASED SUSCEPTIBILITY TO STAPHYLOCOCCAL-ENTEROTOXIN-B INTOXICATIONIN MICE PRIMED WITH ACTINOMYCIN-D

Mice (BALB/cJ, C3H/HeN, and C3H/HeJ) primed with actinomycin D became highly susceptible to lethal Intoxication with staphylococcal enteroto xin B (SEB). The mice underwent toxicosis and toxic shock and died. Ac tinomycin D-primed C3H/HeN and C3H/HeJ mice showed equal sensitivity t o SEB, suggesting that bacterial Lipopolysaccharide derived from gram- negative bacteria in the gut may not be an important cofactor in intox ication. In a time course study of the illness, prominent pathological changes characterized by blood congestion and thickening of alveolar septa were seen Tn the lung, while blood congestion, inflammation, epi thelial cell flattening, and villous blunting were seen in the small i ntestine. In lymphoid tissues, such as the spleen, congestion, inflamm ation, and lymphoid cell depletion were the major reactions. The patho logical features of them!ce had many similarities to those of rhesus m onkeys intoxicated with intravenous SEB. The actinomycin D-primed C3H/ HeJ mice are thus an ideal mouse model for studying SEB toxicosis and toxic shock.