Nonclinical safety and immunogenicity assessment of a combined DTacP vaccine in animal models

The (diphtheria, tetanus, and pertussis [acellular, component] [DTacP]) vaccine is a combined vaccine designed to prevent three potentially fatal diseases including pertussis, tetanus, and diphtheria in both children and adults. We utilized advanced technology to develop a novel DTacP vaccine that was previously unavailable in China. The nonclinical studies were performed to evaluate the immunogenicity, potential toxicity, and local tolerance of the vaccine in animal models. In the immunogenicity study, three batches of the vaccine were intraperitoneally administered to National Institutes of Health (NIH) mice, resulting in 100% seropositivity for all three batches. Additionally, antibody levels notably increased as the immunization dosage increased. In acute toxicity study, no mortality was observed among the animals during the 14-day observation period, and no abnormalities in clinical signs were reported. Active systemic anaphylaxis assessment in guinea pigs showed no evidence of serious allergic reactions in the vaccine groups. In the repeat-dose toxicity study, where five intramuscular doses were administered every 2 weeks, gross autopsy and histopathological examination revealed no vaccine-related systemic pathological changes in rats, with dose site irritant reactions mostly recovered at the end of recovery period. In conclusion, the vaccine demonstrated good local and systemic tolerance, supporting its clinical development.