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Changes in neutrophil surface-receptor expression after stimulation with FMLP, endotoxin, interleukin-8 and activated
1Department of Laboratory medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway. vibeke.videm@medisin.ntnu.no
Scandinavian Journal of Immunology
|January 16, 2004
Summary
Neutrophil activation alters surface receptor expression, with stimulants upregulating beta2-integrins and downregulating l-selectin. Spontaneous degranulation in isolated neutrophils complicates activation studies.
Area of Science:
- Immunology
- Cell Biology
- Hematology
Background:
- Neutrophil activation is a critical process involving changes in surface receptor expression and degranulation.
- Understanding these changes is vital for diagnosing and treating inflammatory and infectious diseases.
Purpose of the Study:
- To compare the surface receptor expression and degranulation of neutrophils stimulated by various agents.
- To evaluate the suitability of different anticoagulants and conditions for studying neutrophil activation.
Main Methods:
- Flow cytometry was used to measure surface expression of beta2-integrins, l-selectin, CR-1, DAF, C5a receptor, ICAM-1, and ICAM-3.
- Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine (FMLP), endotoxin, interleukin-8, or cobra venom factor.
- Myeloperoxidase and lactoferrin levels in supernatants were quantified using enzyme immunoassays.
Main Results:
- All stimulants significantly upregulated beta2-integrins, CR-1, and DAF, and downregulated l-selectin.
- ICAM-3 expression was unchanged or downregulated, while ICAM-1 was only upregulated by FMLP and PMA.
- Spontaneous degranulation in isolated neutrophils and unstimulated neutrophils in lepirudin-anticoagulated blood obscured stimulated responses.
Conclusions:
- Combined measurement of beta2-integrins and l-selectin allows for graded evaluation of early neutrophil activation.
- Isolated neutrophils and certain anticoagulants like lepirudin may not be suitable for studying stimulated neutrophil responses due to spontaneous activation.