Troybodies and pepbodies.

Area of Science:

• Immunotechnology
• Protein Engineering
• Vaccine Development

Background:

• Antibodies with effector functions are typically produced in mammalian cells, limiting bacterial production to non-effector fragments like scFv and Fab.
• Current methods lack efficient bacterial production of functional antibody fragments and targeted T-cell activation strategies.

Purpose of the Study:

• To develop novel antibody fragments (pepbodies) produced in bacteria that retain binding to antibody effector molecules and potentially initiate effector functions.
• To engineer T-cell epitope-antibody fusions (Troybodies) for targeted delivery to antigen-presenting cells (APCs) and enhanced T-cell activation.

Main Methods:

• Isolated peptides binding to antibody effector molecules and cloned them as fusions to scFv and Fab fragments in bacterial expression vectors.
• Genetically inserted T-cell epitopes into antibody constant domains targeting APC surface molecules, creating Troybodies.
• Investigated T-cell epitope loading onto MHC class II on APCs and presentation to T-cells.

Main Results:

• Successfully generated targeting fragments (pepbodies) with the ability to bind antibody effector molecules, some initiating effector functions.
• Demonstrated that T-cell epitopes inserted into antibodies are loaded onto MHC class II on APCs and presented to T-cells.
• Achieved a significant increase (up to four orders of magnitude) in T-cell activation compared to synthetic peptides.

Conclusions:

• Bacterial production of functional antibody fragments (pepbodies) and targeted T-cell activation strategies (Troybodies) are feasible.
• Troybodies enhance T-cell activation significantly, offering a promising platform for vaccine development.
• Further research aims to identify all suitable Ig constant domain loops for T-cell epitope insertion to create a multi-vaccine.