ROLE OF ENDOTOXIN IN ALTERATIONS OF HEPATIC DRUG-METABOLISM BY DIPHTHERIA AND TETANUS TOXOIDS AND PERTUSSIS-VACCINE ADSORBED

Administration of diphtheria and tetanus toxoids and pertussis vaccine adsorbed (DTP vaccine) or endotoxin (LPS) resulted in marked alterations in hepatic drug-metabolizing enzymes in endotoxin-responsive (R) and non-endotoxin-responsive (NR) mice. A single human dose (0.5 ml) of DTP vaccine increased hexobarbital-induced sleep times to 1.6- to 1.8-fold above those of controls in both strains of mice. This effect persisted for 7 days. In contrast, Bordetella pertussis LPS-treated mice showed an increase at 1 day (3.0-fold for R mice and 1.5-fold for NR mice), which returned to control levels by day 7. Furthermore, cytochrome P-450 levels were decreased 30 to 40% 24 h after DTP vaccine administration in both R and NR mice, while after LPS administration they were decreased 30% in R mice and less than 10% in NR mice. Both spleen and liver weights of R and NR mice were increased 7 to 14 days following DTP vaccine administration. However, LPS treatment had no apparent effect on liver weights, and spleen weights of R mice were elevated from days 3 to 7. Histopathologic tissue examination showed random, multifocal inflammation with hepatocyte necrosis after DTP vaccine administration to both R and NR mice and an absence of lesions in LPS-treated mice. Premixing LPS with polymyxin eliminated the increased sleep times, but premixing DTP vaccine with polymyxin did not affect the increased sleep times. Levels of tumor necrosis factor and interleukin-6 in plasma of R mice were markedly increased after DTP and LPS treatment, while NR mice had reduced increases. These results suggest that LPS contributes to the alterations in R and NR mice seen within the first 24 h of vaccine administration but that it is not likely to contribute to the effects observed at later time points.