Immunogenicity of Endolysin PlyC.

Area of Science:

• Microbiology
• Immunology
• Biochemistry

Background:

• Endolysins are bacteriolytic enzymes from bacteriophages, offering an alternative to conventional antibiotics due to their resistance to antimicrobial resistance mechanisms.
• Non-human proteins can elicit specific immune responses, including IgG and IgE-mediated allergic reactions.
• Evaluating the immunogenicity and hypersensitivity potential of endolysins is crucial for their therapeutic development.

Purpose of the Study:

• To assess the general immunogenicity of the antibacterial enzyme PlyC in a human population and a mouse model.
• To identify molecular epitopes of PlyC responsible for immune interactions.
• To evaluate the potential for hypersensitivity and detect PlyC-specific IgE.

Main Methods:

• Immunization of a mouse model with PlyC.
• Analysis of PlyC-specific IgG responses and epitope mapping.
• Screening of human serum samples for IgG reactivity to PlyC subunits.
• Assessment of hypersensitivity and IgE responses in mice and humans.

Main Results:

• PlyC induced significant IgG production in mice, with IgG interacting with four immunogenic regions on the PlyCA subunit.
• Approximately 10% of the human population exhibited IgG reactivity to the PlyCB subunit, likely due to cross-reactions in naive serum.
• No PlyC-specific IgE was detected in either the mouse model or the human population, indicating a lack of hypersensitivity.

Conclusions:

• PlyC is immunogenic, inducing a robust IgG response without causing hypersensitivity.
• The identified immunogenic regions on PlyC provide targets for further immunological studies.
• The absence of PlyC-specific IgE suggests a favorable safety profile for potential therapeutic applications of endolysins.