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Interfering effect of diphtheria-tetanus-acellular pertussis combined (DTaP) vaccines on the bacterial endotoxin test
M Ochiai1, A Yamamoto, M Kataoka
1Department of Safety Research on Biologics, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.
Abstract:
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 spiking was seen for some of the batches. The interfering DTaP vaccine batches, however, showed no significant effect onin vitro TNF-alpha induction in RAW264.7 cells and pyrogenicity in rabbits of spiked endotoxin. Aluminium hydroxide gel in the vaccines was suggested to be one of the causes of the interference. Accordingly, a careful evaluation of the interfering effect was assumed crucial for the effective application of the endotoxin test to check residual biological activity of endotoxin in DTaP vaccines.
Insights
The Limulus amebocyte lysate (LAL) endotoxin test showed time-dependent interference with DTaP vaccines, but this did not affect vaccine safety. Careful evaluation is crucial for accurate endotoxin testing in DTaP vaccines.
Area of Science:
- Microbiology
- Immunology
- Vaccinology
Background:
- The Limulus amebocyte lysate (LAL) assay is a standard method for endotoxin detection.
- Diphtheria, tetanus, and acellular pertussis (DTaP) vaccines are widely used globally.
- Ensuring the safety and efficacy of vaccines requires accurate detection of residual endotoxins.
Purpose of the Study:
- To evaluate the applicability of the LAL endotoxin test for DTaP vaccines.
- To investigate potential interference between DTaP vaccine components and endotoxin detection.
- To assess the impact of observed interference on vaccine safety indicators.
Main Methods:
- DTaP vaccine batches were spiked with endotoxin.
- Limulus amebocyte lysate (LAL) assay was used to measure endotoxin activity over time.
- In vitro tumor necrosis factor-alpha (TNF-α) induction in RAW264.7 cells was assessed.
- In vivo pyrogenicity in rabbits was evaluated.
Main Results:
- No immediate interference was observed in the LAL assay.
- Some DTaP batches exhibited time-dependent interference with LAL activity.
- The observed interference did not affect in vitro TNF-α induction or in vivo pyrogenicity.
- Aluminium hydroxide gel was identified as a potential cause of interference.
Conclusions:
- The LAL test can be applied to DTaP vaccines, but potential time-dependent interference must be considered.
- Interference in the LAL assay does not necessarily correlate with reduced vaccine safety.
- Thorough evaluation of interference effects is essential for reliable endotoxin testing in DTaP vaccines.