Dr. Joaquin Pellegrini - Emerging Immune Players in Intracellular Bacterial Infections - IPBS-Toulouse, Seminar Room

Dr. Joaquin Pellegrini

INFINITY, Toulouse

Emerging Immune Players in Intracellular Bacterial Infections

Plasmacytoid dendritic cells (pDC) are renowned for their ability to produce massive amounts of type I interferons during viral infections, yet their role in bacterial defense has remained largely enigmatic. We discovered that two members of the SLAM receptor family, SLAMF7 and SLAMF8, act as molecular regulators of pDC function during intracellular bacterial infection, coordinating a signaling axis through NF-κB, IRF7, and STAT-1 while controlling mitochondrial reactive oxygen species. Strikingly, this same protective mechanism creates a permissive niche for bacterial persistence. These findings, supported by patient-derived data from salmonellosis and brucellosis cohorts, open new perspectives for understanding, and potentially targeting, pDC responses in chronic infectious disease. Looking ahead, our laboratory at Infinity (Toulouse) is now exploring how these immune circuits operate across intracellular bacterial pathogens, integrating translational networks with clinical centers in Toulouse and Argentina, and working toward new host-directed therapies and next-generation vaccination strategies against bacteria for which no effective vaccines currently exist.

Selected references

• SLAMF7 and SLAMF8 receptors shape human plasmacytoid dendritic cell responses to intracellular bacteria. Pellegrini JM, Keriel A, Gorvel L, Hanniffy S, Arce-Gorvel V, Bosilkovski M, Solera J, Méresse S, Mémet S & Gorvel JP. (2025) The Journal of Clinical Investigation 135(8):e182467
• Brucella impairs T lymphocyte responsiveness by mobilizing IL-1RA-secreting omental neutrophils. Pellegrini JM*, González-Espinoza G*, Shayan RR, Hysenaj L, Arce-Gorvel V, Zhao Y, Hanniffy S, Castillo-Zeledon A, Loperena-Barber M, Lelouard H, Celis-Gutierrez J, Bosilkovski M, Barquero-Calvo E, Moreno E, Conde-Alvarez R, Moriyon I, Gorvel JP, Mémet S. (2025) Nature Communications 16, 862.