Interleukin-1 receptor type I gene-deficient mice are less susceptible to Staphylococcus epidermidis biomaterial-associated infection than are wild-type mice

Elevated concentrations of interleukin-1 (IL-1) were found in tissue surrou nding biomaterials infected with Staphylococcus epidermidis. To determine t he role of IL-1 in biomaterial-associated infection (BAI), IL-1 receptor ty pe I-deficient (IL-1R(-/-)) and wild-type mice received subcutaneous implan ts of silicon elastomer (SE) or polyvinylpyrrolidone-grafted SE (SEpvp), co mbined with an injection of 10(6) CFU of S. epidermidis or sterile saline. Neither mouse strain was susceptible to BAI around SE. IL-1R(-/-) mice with SEpvp implants had a no abscess formation and a reduced susceptibility to persistent S. epidermidis infection. The normal foreign body response, char acterized by giant-cell formation and encapsulation, was delayed around SEp vp in wildtype mice but not in IL-1R(-/-) mice. This coincided with enhance d local IL-4 production in IL-1R(-/-) mice. These data suggest that inhibit ion of local IL-1 activity may be beneficial for the outcome of BAI.