Bacteriophage lambda is a highly stable DNA vaccine delivery vehicle

Area of Science:

• Biotechnology
• Virology
• Vaccine Development

Background:

• Bacteriophage lambda is being explored as a DNA vaccine delivery system.
• Understanding phage stability is crucial for vaccine formulation and storage.

Purpose of the Study:

• To evaluate the stability of whole bacteriophage lambda particles under various storage and environmental conditions.
• To determine the impact of stabilizers and desiccation on phage viability.
• To assess the potential for oral administration of phage-based vaccines.

Main Methods:

• Assessed phage lambda titre in liquid suspension at different temperatures (4°C, -70°C, 20°C, 37°C, 42°C).
• Evaluated stability after freeze-thawing cycles.
• Investigated viability and half-life of freeze-dried phage with and without stabilizers (dry skim milk, trehalose).
• Tested phage stability in water and across a pH range (pH 3-11).

Main Results:

• Phage lambda remained stable in liquid suspension for 6 months at 4°C and -70°C, unaffected by freeze-thawing.
• Half-lives in suspension ranged from 36 days at 20°C to 2.3 days at 42°C.
• Freeze-drying resulted in 5-20% residual viability; trehalose significantly improved desiccated phage stability.
• Desiccated phage showed extended half-lives, with trehalose-stabilized phage lasting up to 100 days at 20°C.
• Liquid suspensions were stable across pH 3-11 for 24 hours.

Conclusions:

• Whole bacteriophage lambda particles exhibit remarkable stability under various conditions, including refrigeration and freeze-drying.
• Trehalose is an effective stabilizer for desiccated phage lambda, enhancing long-term viability.
• The stability across a broad pH range suggests bacteriophage lambda holds promise for oral DNA vaccine delivery systems.