New Publication by LMU: Interferon-induced activation of dendritic cells and monocytes

Yellow Fever Vaccination: How Strong Immune Responses Are Triggered

Researchers show how specific immune cells are activated by the vaccine – an important starting point for the development of new vaccines.

The yellow fever vaccine (YF17D) using the live-attenuated vaccine is one of the most effective immunizations available. A single dose provides robust and long-lasting protection. Due to the strength of the immune response it generates, this vaccine serves as an excellent model for studying effective immune defense mechanisms against viral infections.

However, the precise immune mechanisms underlying its powerful effect have remained unclear—until now.

A team led by immunology Prof. Anne Krug (LMU Biomedical Center), in collaboration with Prof. Simon Rothenfußer (LMU Klinikum) investigated how specific immune cells (dendritic cells DCs) and monocytes) are activated following vaccination with YF17D. Their work sheds new light on the early immune responses that lead to protective immunity.

🔬 Key Findings

✅ Dendritic cell and monocyte activation: Various dendritic cells and monocyte cell types were analyzed in the blood of over 200 healthy adults before and after vaccination. Following vaccination, many of these immune cells showed typical activation by so-called interferons—messenger molecules that play a key role in the body’s defense against viruses.

✅ Role of SIGLEC-1: A particularly striking finding was the cell surface molecule SIGLEC-1, which became more prominent on certain cell types within one week of vaccination and was associated with the rapid formation of protective antibodies against the yellow fever virus.

✅ Implications for Vaccine Development: The study provides new insights into how the immune system responds to a highly effective viral vaccine. These findings could support the development of new vaccines that offer rapid protection, for example in the context of emerging epidemics. Additionally, SIGLEC-1 may serve as a useful biomarker in future vaccine studies.

Read the publication here: https://www.pnas.org/doi/10.1073/pnas.2422236122

Interferon-induced activation of dendritic cells and monocytes by yellow fever vaccination correlates with early antibody responses

Elena Winheim, Antonio Santos-Peral, Tamara Ehm, Linus Rinke, Sandra Riemer, Magdalena Zaucha, Sebastian Goresch, Lisa Lehmann, Katharina Eisenächer, Michael Pritsch, Giovanna Barba-Spaeth, Tobias Straub, Simon Rothenfusser, Anne B. Krug

Proceedings of the National Academy of Sciences of the United States of America

Published: May 7th, 2025