# Photoconverted cells allow rapid assessment of vaccine adjuvant potency in mice

## TL;DR

This paper introduces a fast and efficient method using KikGR mice to assess vaccine adjuvant potency by tracking migratory dendritic cells and their link to CD8+ T cell responses.

## Contribution

A novel photoconversion-based method using KikGR mice enables rapid, real-time tracking of migratory dendritic cells for adjuvant evaluation.

## Key findings

- Migratory dendritic cells serve as a reliable predictor of adjuvant potency and CD8+ T cell priming.
- The KikGR-red cell count correlates with anti-tumor efficacy and CD8+ T cell responses.
- Blocking CCR7 impairs dendritic cell migration and reduces CD8+ T cell activation.

## Abstract

Identifying vaccine adjuvants that optimally enhance CD8+ T cell responses remain a challenge, often requiring time-consuming and resource-intensive methods. Here, we introduce a photoconversion-based approach using KikGR mice to track migratory dendritic cells (Mig DCs) within 48 h post-vaccination. This method enables real-time visualization of skin-derived Mig DCs migration to draining lymph nodes (dLNs), providing an early and reliable predictor of CD8+ T cell priming and anti-tumor efficacy. Unlike traditional techniques that demand extensive experimentation, this system allows for faster, cost-effective screening of adjuvants. We further demonstrate that blocking CCR7 significantly reduces Mig DCs migration, impairing CD8+ T cell responses. Our approach revolutionizes adjuvant evaluation, enabling swift and accurate immune assessments, particularly in therapeutic vaccine development.

•Migratory DCs serve as predictor for rapid assessment of adjuvants’ potency•The KikGR mice offer real-time tracking of migratory DCs to dLNs•The quantity of KikGR-red cells correlates with CD8+ T cell responses

Migratory DCs serve as predictor for rapid assessment of adjuvants’ potency

The KikGR mice offer real-time tracking of migratory DCs to dLNs

The quantity of KikGR-red cells correlates with CD8+ T cell responses

Immunology; Methodology in biological sciences