IMMUNOLOGY2026™ Conference Recordings For Attendees-Neutrophil diversity in the host defense niche

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Video Summary

The speaker discusses unpublished work on neutrophil phenotypic diversity during host defense, focusing on skin biofilm infection with <em>Staphylococcus aureus</em>. Using intravital microscopy and spectral flow cytometry, they show that neutrophils rapidly extravasate, swarm, degranulate, and help contain biofilm infections. A key finding is that mature CD101-high neutrophils can convert in tissue into a CD101-low, side-scatter-low state associated with higher ICAM-1 and PD-L1 expression, greater bacterial binding/phagocytosis, reduced granularity, and lower DNA content. This phenotype appears after tissue entry and is tracked with photoactivatable reporter mice. The CD101-low state is enriched in biofilm infection but not in aseptic wounds or planktonic infection, suggesting it reflects a specialized response to difficult, structured pathogens rather than infection in general. The speaker proposes that these neutrophils support a cooperative swarm architecture involving degranulation and extracellular DNA for pathogen containment.

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Date April 18, 2026 1:15 PM - 1:30 PM

Room 156

Session Microenvironmental Influences on Innate Immunity

Speaker Marie Siwicki

Track Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)

Year 2026

Keywords

neutrophil phenotypic diversity

Staphylococcus aureus biofilm

host defense

CD101-low neutrophils

intravital microscopy

April 18, 2026 1:15 PM - 1:30 PM

156

Microenvironmental Influences on Innate Immunity

Marie Siwicki

Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)

2026