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

The detection of foreign antigens in vivo has relied on fluorescent conjugation or indirect read-outs such as antigen presentation. In our studies, we found that these widely used techniques had several technical limitations that have precluded a complete picture of antigen trafficking or retention across lymph node cell types. To address these limitations, we developed a 'molecular tracking device' to follow the distribution, acquisition, and retention of antigen in the lymph node. Utilizing an antigen conjugated to a nuclease-resistant DNA tag, acting as a combined antigen-adjuvant conjugate, and single-cell mRNA sequencing, we quantified antigen abundance in the lymph node. Variable antigen levels enabled the identification of caveolar endocytosis as a mechanism of antigen acquisition or retention in lymphatic endothelial cells. Thus, these molecular tracking devices enable new approaches to study dynamic tissue dissemination of antigen-adjuvant conjugates and identify new mechanisms of antigen acquisition and retention at cellular resolution in vivo.

Automated summary

Traditional techniques for detecting foreign antigens in vivo have limitations, prompting the development of a "molecular tracking device" to better study the distribution and retention of antigens in lymph nodes. By utilizing an antigen conjugated to a nuclease-resistant DNA tag and single-cell mRNA sequencing, antigen abundance in lymph nodes can be quantified. This advancement enables new approaches to study the dissemination of antigen-adjuvant conjugates and to identify mechanisms of antigen acquisition and retention at a cellular level in vivo.