M. Ochiai et al., Interfering effect of diphtheria-tetanus-acellular pertussis combined (DTaP) vaccines on the bacterial endotoxin test, BIOLOGICALS, 29(1), 2001, pp. 55-58
We evaluated applicability of the endotoxin test to DTaP vaccines. Although
no DTaP vaccine batches showed immediate interference with the activating
activity of spiked endotoxin on the clotting of Limulus amaebocyte lysate (
LAL), a gradually progressing interference depending on the time after spik
ing was seen for some of the batches. The interfering DTaP vaccine batches,
however, showed no significant effect on in vitro TNF-alpha induction in R
AW264.7 cells and pyrogenicity in rabbits of spiked endotoxin. Aluminium hy
droxide gel in the vaccines was suggested to be one of the causes of the in
terference. Accordingly, a careful evaluation of the interfering effect was
assumed crucial for the effective application of the endotoxin test to che
ck residual biological activity of endotoxin in DTaP vaccines.