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Functional integrity of cytokineplasts: specific chemotactic and capping responses
Journal of Immunology (Baltimore, Md. : 1950)
|September 1, 1985
Summary
Heat-induced cytokineplasts (CKP) from human polymorphonuclear leukocytes (PMN) exhibit chemotaxis and receptor capping, unlike cytochalasin B-treated fragments. Both CKP and CB-cytoplasts retain N-formyl-peptide receptors, but differ in respiratory burst activity, offering complementary insights into PMN function.
Area of Science:
- Immunology
- Cell Biology
Background:
- Human blood polymorphonuclear leukocytes (PMN) generate various membrane-bound cytoplasmic fragments.
- Cytokineplasts (CKP) are heat-induced, motile, anucleate PMN fragments.
- CB-cytoplasts are high-speed centrifugation fragments from cytochalasin B-treated PMN.
Purpose of the Study:
- To compare the functional capabilities of CKP and CB-cytoplasts.
- To investigate chemotaxis, capping, N-formyl-peptide receptor presence, and respiratory burst activity in these fragments.
- To determine the utility of these distinct cytoplasts in analyzing PMN function.
Main Methods:
- Induction of CKP by heat application to human PMN.
- Preparation of CB-cytoplasts via cytochalasin B treatment and high-speed centrifugation.
- Chemotaxis assays using N-formyl-methionyl-leucyl-phenylalanine (fmlp) and zymosan-activated serum.
- Affinity labeling and autoradiography to detect N-formyl-peptide receptors.
- Fluorescence microscopy with a monoclonal antibody (PMN7C3) to study receptor capping.
- Assessment of respiratory burst activity using phorbol myristate acetate and fmlp.
Main Results:
- CKP demonstrated chemotaxis to fmlp and zymosan-activated serum, while CB-cytoplasts did not.
- Both CKP and CB-cytoplasts possessed N-formyl-peptide receptors.
- CKP exhibited normal receptor capping upon warming, whereas CB-cytoplasts showed impaired capping.
- CKP lacked respiratory burst activity, while CB-cytoplasts exhibited this activity.
- The two types of cytoplasts displayed complementary functional characteristics.
Conclusions:
- Heat-induced CKP and CB-cytoplasts represent distinct PMN-derived fragments with differing functional properties.
- CKP are capable of chemotaxis and capping, retaining specific receptors.
- CB-cytoplasts, while lacking chemotaxis and capping, possess respiratory burst activity.
- These complementary cytoplasts serve as valuable tools for dissecting specific PMN functions.