Influence of storage conditions on the toxicity of whole-cell pertussis vaccine in outbred mice
INTRODUCTION. Although whole-cell pertussis vaccine (WCPV) is highly effective, its widespread use is limited by adverse reactions (increased body temperature, administration site oedema, allergic reactions, and febrile seizures). Therefore, there is a need to explore strategies for reducing the tox...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | Russian |
| Published: |
Ministry of Health of the Russian Federation. Federal State Budgetary Institution «Scientific Centre for Expert Evaluation of Medicinal Products»
2025-04-01
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| Series: | Биопрепараты: Профилактика, диагностика, лечение |
| Subjects: | |
| Online Access: | https://www.biopreparations.ru/jour/article/view/629 |
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| Summary: | INTRODUCTION. Although whole-cell pertussis vaccine (WCPV) is highly effective, its widespread use is limited by adverse reactions (increased body temperature, administration site oedema, allergic reactions, and febrile seizures). Therefore, there is a need to explore strategies for reducing the toxicity of WCPV.AIM. This study aimed to evaluate the toxicity of WCPV in mice after storing WCPV under different conditions.MATERIALS AND METHODS. This study focused on Bordetella pertussis strains, including vaccine production strains and circulating strains isolated from children with pertussis. Ten WCPV samples were prepared by washing the grown cultures and adding formaldehyde (inactivating agent) and thimerosal (preservative) to the bacterial suspensions. Outbred mice were randomised into 10 test groups and 1 control group (10 animals per group). The test groups received intraperitoneal injections of the WCPV samples, while the control group received 0.9% sodium chloride with thimerosal. Mice were weighed before injection, as well as on Days 1 and 7 after injection. The weighing was timed to coincide with the peak activity of the main B. pertussis toxins, lipo-oligosaccharide (Day 1) and pertussis toxin (Day 7). The specific safety index was calculated as the ratio of the weight gain of the test animals to the weight gain of the control animals (in %) and was monitored for the WCPV samples throughout the WCPV shelf life (12 months).RESULTS. On Day 1 after injection, the B. pertussis suspensions kept with the inactivating agent under recommended storage conditions for 1–3 months caused a 2.84% decrease in the body weight of mice from the baseline weight, and the suspensions inactivated for 10–12 months caused a 1.62% weight loss relative to the baseline. On Day 7 after injection, the mice that received the B. pertussis suspensions inactivated for 1–3 months showed a 31.0% increase from the baseline weight, and the mice that received the suspensions inactivated for 10–12 months demonstrated a 43.22% weight gain. The suspensions inactivated for 1–3 months and 10–12 months had specific safety indices of 69.38% and 84.31%, respectively. According to these findings, the residual toxicity of WCPV decreased after 12 months of storage, and the process of pertussis toxin inactivation lasted throughout the entire WCPV shelf life. Spearman’s correlation coefficient, characterising the strength of the relationship between the specific safety index and the weight gain of mice, was 0.55 (p<0.01) on Day 7 (a noticeably strong relationship) and 0.349 (p<0.01) on Day 1 (a moderately strong relationship).CONCLUSIONS. The results suggest a more complete detoxification of pertussis toxin in the samples of WCPV kept with the inactivating agent under recommended storage conditions for at least 10–12 months compared with that after a shorter period. To improve the safety of DTP vaccines, it is advisable to use WCPV batches stored for 10–12 months. |
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| ISSN: | 2221-996X 2619-1156 |