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An amino acid substitution in a capsid protein enhances phage survival in mouse circulatory system more than a

Christal L Vitiello1, Carl R Merril, Sankar Adhya

  • 1Section of Developmental Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Virus Research
|August 2, 2005
PubMed

Insights

Researchers engineered a bacteriophage lambda mutant, lambdaArgo phage, to prolong its circulation time in mice. A single mutation in the E protein was identified as sufficient for this "long-circulating" phenotype, aiding innate immunity studies and phage therapy development.

Area of Science:

  • Virology
  • Immunology
  • Microbial Genetics

Background:

  • Bacteriophage lambda clearance in mice is rapid, with titers decreasing significantly within 48 hours.
  • Previous selection methods yielded
  • long-circulating
  • lambda phage (lambdaArgo phage) with multiple mutations, including one in the E protein.

Purpose of the Study:

  • To determine if a single mutation in the phage lambda E protein is sufficient to confer a
  • long-circulating
  • phenotype.
  • To develop an isogenic pair of phage for studying innate immune recognition and phage therapy.

Main Methods:

  • Site-directed mutagenesis to create an isogenic pair of phage lambda.
  • Comparison of circulation kinetics between wild-type and mutant phage in mice.
  • Characterization of the E protein substitution (glutamic acid to lysine at residue 158).

Main Results:

  • A single amino acid substitution (E protein, residue 158) is sufficient to confer the
  • long-circulating
  • phenotype.
  • The engineered phage exhibited significantly prolonged circulation times compared to wild-type phage.
  • An isogenic pair of phage was successfully created.

Conclusions:

  • The specific E protein mutation is a key driver of prolonged phage circulation.
  • This research provides a valuable tool for investigating innate immune responses to viruses.
  • The findings support the development of enhanced bacteriophage strains for therapeutic applications against bacterial infections.

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