Molecular tracking devices quantify antigen distribution and archiving in the murine lymph node

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Current methods for detecting foreign antigens in vivo, such as fluorescent conjugation and antigen presentation assays, have limitations in fully characterizing antigen trafficking and retention within lymph node cell types.
• A comprehensive understanding of antigen dynamics is crucial for developing effective vaccines and immunotherapies.

Purpose of the Study:

• To develop a novel molecular tracking device for precise in vivo tracking of antigen distribution, acquisition, and retention within lymph nodes.
• To overcome the limitations of existing techniques and provide a detailed cellular-level view of antigen dynamics.

Main Methods:

• Developed a 'molecular tracking device' by conjugating an antigen to a nuclease-resistant DNA tag, creating a combined antigen-adjuvant conjugate.
• Employed single-cell mRNA sequencing to quantify antigen abundance within individual lymph node cells.
• Analyzed variable antigen levels to identify cellular mechanisms of antigen uptake and retention.

Main Results:

• The molecular tracking device successfully monitored the distribution, acquisition, and retention of antigens in the lymph node.
• Identified caveolar endocytosis as a key mechanism for antigen acquisition and retention in lymphatic endothelial cells.
• Demonstrated the ability to quantify antigen abundance at a single-cell level, providing unprecedented resolution.

Conclusions:

• The developed molecular tracking devices offer a powerful new approach for studying the dynamic dissemination of antigen-adjuvant conjugates in tissues.
• This technology enables the discovery of novel mechanisms of antigen acquisition and retention at the cellular level in vivo.
• Provides a foundation for future research into immune responses and the development of targeted immunotherapies.