Pre-exposure to phage particles reduces their antibacterial therapeutic efficacy both in vitro and in vivo

Area of Science:

• Microbiology
• Immunology
• Bacteriophage Therapy

Background:

• Phage therapy offers a potential solution for drug-resistant bacterial infections.
• Understanding immune responses to phages is crucial for optimizing therapeutic strategies.

Purpose of the Study:

• To investigate the impact of pre-exposure to phage JD007 on the efficacy of subsequent phage therapy against Staphylococcus aureus infections in mice.
• To characterize the immune response, including antibody production, following phage exposure.

Main Methods:

• Mice were intradermally exposed to Staphylococcus aureus phage JD007.
• Phage-specific IgM and IgG antibodies were quantified using ELISA.
• Mice were infected with S. aureus to create a dermal abscess model.
• Therapeutic efficacy of phage JD007 was evaluated in pre-exposed and naive mice.
• Western blot analysis identified anti-phage antibodies targeting key phage proteins.

Main Results:

• Pre-exposure to JD007 induced specific IgM and IgG antibodies, peaking at days 7 and 30, respectively.
• In vitro neutralization assays confirmed that antibodies reduced phage infectivity.
• Mice with multiple prior exposures exhibited diminished therapeutic outcomes, including delayed healing and exacerbated abscesses.
• Single pre-exposure did not significantly alter abscess area compared to naive mice.

Conclusions:

• Pre-exposure to phage particles can elicit neutralizing antibodies, potentially compromising subsequent phage therapy effectiveness.
• Repeated phage exposure may lead to delayed recovery or worsening of Staphylococcus aureus-associated dermal abscesses.
• The findings highlight the importance of considering host immune responses in the application of phage therapy.