[Development studies of lyophilized standard diphtheria-tetanus-pertussis vaccines]

Area of Science:

• Vaccinology
• Immunology
• Microbiology

Background:

• Diphtheria, tetanus, and pertussis (DTP) vaccines are crucial for public health.
• Developing stable vaccine formulations is essential for widespread and long-term efficacy.
• Lyophilization offers a method to enhance vaccine stability.

Purpose of the Study:

• To prepare and evaluate the immunogenicity and stability of lyophilized diphtheria, tetanus, and pertussis vaccine formulations.
• To assess the potency and antibody responses induced by DTP, DT, Td, and TT lyophilized adsorbed vaccines.
• To compare the stability of lyophilized vaccine components against liquid adsorbed vaccines.

Main Methods:

• Preparation of Alhydrogel-adsorbed vaccine formulations (DTP, DT, Td, TT) with stabilizers.
• Lyophilization of the prepared vaccine formulations.
• In vivo immunogenicity testing using lethal challenge tests in mice.
• In vitro assessment of antibody levels (anti-tetanus IgG, anti-diphtheria IgG, anti-B.pertussis fimbria IgG) via ELISA and microagglutination tests.

Main Results:

• Lyophilized adsorbed (LA)-DTP, LA-DT, LA-Td, and LA-TT vaccines showed high tetanus component potencies ranging from 96.2 to 144.86 IU/ml.
• High levels of anti-tetanus IgG, anti-diphtheria IgG, and anti-B.pertussis fimbria IgG antibodies were detected in immunized mice.
• Vaccine components demonstrated significant stability in lyophilized formulations compared to liquid adsorbed vaccines.

Conclusions:

• The developed lyophilized vaccine formulations (DTP, DT, Td, TT) exhibit robust immunogenicity and stability.
• These formulations show promise as effective and stable vaccines against diphtheria, tetanus, and pertussis.
• Further calibration against WHO standards is recommended for their use as official standard vaccines.