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Updated: Sep 28, 2026
Detecting Migration and Infiltration of Neutrophils in Mice
Published on: February 6, 2020
Recruitment of murine neutrophils in vivo through endogenous sialidase activity
Alan S Cross1, Serhan Sakarya, Salahaldin Rifat
1Department of Medicine, Veterans Affairs Medical Center, Baltimore, Maryland 21201, USA. across@umm.edu
Abstract:
Upon activation with various noncytokine stimuli, polymorphonuclear leukocytes (PMNs) mobilize intracellular sialidase to the plasma membrane, where the sialidase releases sialic acid from the cell surface. This desialylation enhances PMN adherence, spreading, deformability, and motility, functions critical to diapedesis. We now have examined the role of sialidase activity in PMN adhesion to and migration across the endothelium in vivo. A polyclonal antibody prepared against Clostridium perfringens neuraminidase 1) detected surface expression of sialidase on human PMNs stimulated with IL-8 in vitro and on murine PMNs stimulated in vivo, but not on that of unstimulated cells, 2) recognized proteins in human PMN lysates and granule preparations that were not detected by preimmune antibody, 3) inhibited bacterial neuraminidase and human PMN sialidase activities in vitro, and 4) inhibited both pulmonary leukostasis in mice systemically infused with cobra venom factor and intrapulmonary transendothelial migration of PMNs into the bronchoalveolar compartment of mice intranasally challenged with interleukin-8. We conclude that the chemokine interleukin-8, like other PMN agonists, induces the translocation of sialidase to the PMN surface and that surface expression of this sialidase is a prerequisite to PMN recruitment in vivo. The ability of antibodies raised against a prokaryotic neuraminidase to recognize eukaryotic sialidase extends the concept of the neuraminidase superfamily to mammalian enzymes. Inhibition of mobilized endogenous sialidase may provide a novel strategy for limiting the inflammatory response.
Insights
Polymorphonuclear leukocytes (PMNs) use surface sialidase to enhance migration. This study shows sialidase is crucial for PMN recruitment in vivo, offering a potential target for anti-inflammatory strategies.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Polymorphonuclear leukocytes (PMNs) are critical immune cells involved in inflammatory responses.
- PMN activation leads to the mobilization of intracellular sialidase to the plasma membrane, releasing sialic acid and enhancing cell functions like adherence and motility.
- This desialylation process is essential for PMN diapedesis, the process of migrating through blood vessel walls.
Purpose of the Study:
- To investigate the role of sialidase activity in PMN adhesion to and migration across the endothelium in vivo.
- To determine if surface expression of sialidase is a prerequisite for PMN recruitment.
Main Methods:
- Development of a polyclonal antibody against Clostridium perfringens neuraminidase.
- Detection of surface sialidase expression on human and murine PMNs using the antibody.
- Inhibition of bacterial and human PMN sialidase activities in vitro.
- Assessment of the antibody's effect on pulmonary leukostasis and intrapulmonary PMN migration in vivo models.
Main Results:
- The antibody detected surface sialidase on stimulated PMNs but not unstimulated cells.
- The antibody recognized specific proteins in PMN lysates and granule preparations.
- The antibody inhibited both bacterial and human PMN sialidase activities in vitro.
- The antibody significantly inhibited pulmonary leukostasis and PMN transendothelial migration in vivo.
Conclusions:
- Chemokine interleukin-8 (IL-8) induces sialidase translocation to the PMN surface, similar to other PMN agonists.
- Surface expression of sialidase is essential for PMN recruitment in vivo.
- Antibodies against prokaryotic neuraminidase can recognize eukaryotic sialidase, expanding the neuraminidase superfamily concept.
- Inhibiting mobilized endogenous sialidase presents a novel strategy for managing inflammatory responses.
