Yingtai: Vaccine Types And Technical Key Points Suitable for Low-Temperature Prolonged Sterilization

Yingtai: Vaccine Types and Technical Key Points Suitable for Low-Temperature Prolonged Sterilization  

Low-temperature prolonged sterilization (typically 60-80°C for several hours to days) is primarily used to inactivate pathogens while preserving antigenic structures, especially for vaccines sensitive to high temperatures.  

 I. Inactivated Viral Vaccines  

Influenza Inactivated Vaccine  

- Inactivation parameters: 56°C × 48 hours or 60°C × 6 hours.  

- Advantage: Maintains hemagglutinin (HA) and neuraminidase (NA) epitopes, enhancing immunogenicity.  

- Case study: Graded temperature inactivation process (55°C → 60°C × 4h).  

Polio Inactivated Vaccine (IPV)  

- Inactivation parameters: 37°C × 10 days (with formaldehyde) or 65°C × 2 hours (improved thermal inactivation process).  

- Key point: Low-temperature inactivation avoids D-antigen conformational damage, ensuring neutralization antibody titers meet standards.  

Japanese Encephalitis Inactivated Vaccine  

- Inactivation parameters: 60°C × 4 hours combined with 0.025% formaldehyde treatment.  

- Effect: Viral titer reduction >6 lg, antigen activity retention >95%.  

II. Inactivated Bacterial Vaccines  

Pertussis Inactivated Vaccine  

- Inactivation parameters: Traditional 80°C × 30 minutes → optimized to 60°C × 8 hours.  

- Improvement: Reduces degradation of pertussis toxin (PT) and filamentous hemagglutinin (FHA), increasing efficacy by 20%.  

Cholera Inactivated Vaccine  

- Inactivation parameters: 56°C × 24 hours (whole-cell) or 65°C × 2 hours (O-antigen extract).  

- Characteristic: Preserves lipopolysaccharide (LPS) structure, stimulating mucosal immune response.  

III. Emerging Vaccine Technologies  

mRNA Vaccine Carrier Inactivation  

- Inactivation parameters: 70°C × 1 hour (lipid nanoparticle (LNP)-encapsulated mRNA).  

- Purpose: Inactivates potential exogenous viral contamination (e.g., retroviruses) while maintaining mRNA integrity.  

Viral Vector Vaccines (e.g., Adenovirus)  

- Inactivation parameters: 65°C × 6 hours (physical inactivation replacing chemical inactivation).  

- Advantage: Avoids immune interference caused by residual chemical inactivators (e.g., β-propiolactone).  

IV. Key Process Control Points  

- Temperature uniformity: Sterilization equipment temperature variation ≤ ±1°C (e.g., forced convection oven).  

- Inactivation validation: Three consecutive passages in African green monkey kidney (Vero) cells to confirm no live virus residue.  

- Antigen stability monitoring: Dynamic light scattering (DLS) to detect particle size changes (allowed fluctuation ±5%), ELISA to evaluate epitope retention rate.  

V. Limitations and Solutions  

- Challenge: Long inactivation cycles (>6 hours) reduce production efficiency.  

- Improvement strategies:  

  - Pulsed electric field assistance: 50°C × 2 hours + high-voltage pulses (20 kV/cm), shortening inactivation time by 50%.  

  - Nanomaterial thermal enhancement: Adding carbon nanotubes (CNTs) improves heat transfer efficiency, enabling uniform and rapid inactivation.  

Conclusion  

Traditional inactivated vaccines such as influenza, polio, and cholera, as well as novel vaccines like mRNA carriers and adenovirus vectors, can achieve safe and efficient pathogen inactivation through low-temperature prolonged sterilization. The core technology lies in balancing thorough inactivation with antigen structure preservation, requiring optimization of temperature-time parameters and process validation methods based on specific vaccine characteristics.