"Inverse" effects of cortisone in experimental infection of mice

Hydrocortisone (HC) ameliorated the course of experimental infection with E. coli given intraperitoneally. In experiments with Staphylococcus aureus and treatment with endotoxin on the day of infection, HC had also a beneficial effect, however only when LPS was injected intraperitoneally and bacteria intravenously. With the footpad swelling reaction as a model for cellular immunity it could be shown that HC alone reduced the reactivity by 75 per cent. Under endotoxin treatment, however, HC induced further inhibition when LPS was given intraperitoneally the day of sensitization but changing to a stimulatory effect when LPS was given two days later. In case of intravenous application of LPS, HC had no effect.