SUSCEPTIBILITY TO LOCAL AND SYSTEMIC BACTERIAL-INFECTIONS IN INTERCELLULAR-ADHESION MOLECULE 1-DEFICIENT TRANSGENIC MICE

The contribution of intercellular adhesion molecule 1 (ICAM-1) during systemic and local bacterial infections was studied in transgenic ICAM -1-deficient and control mice that were injected intraperitoneally (ip ) or intradermally (id) with Escherichia coli, Pseudomonas aeruginasa, or Staphylococcus aureus. Mortality rates, blood cultures, white bloo d cell (WBC) counts and absolute neutrophil counts (ANCs) were obtaine d daily until cultures were sterile. Six and 24 h after injections, au topsies were done on randomly selected ip-inoculated mice and biopsies were done on randomly selected id-inoculated mice. Survival rates wer e similar. In ICAM-1-deficient mice, ip P. aeruginosa resulted in high er incidences of bacteremia at 24 h (P = .003) and 48 h (P = .002); id S. aureus resulted in larger skin lesions (P = .026). Leukocytosis pe rsisted in ICAM-1-deficient mice 6 h after ip injection of E. coli; ho wever, WBC counts and ANCs in peritoneal fluid did not differ. Althoug h the inflammatory responses were similar histologically in ICAM-1-def icient and normal mice, differences in site- and stimulus-specific sus ceptibilities were noted.