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Inhibition of polymorphonuclear leucocyte locomotion by surface-bound antigen-antibody complexes
Abstract:
Locomotion of polymorphonuclear leucocytes (PMNL) on solid surfaces with bound antigen-antibody complexes was studied. The amount of surface-bound antibody was determined with ellipsometry, a surface-sensitive optical method. Locomotion of PMNL was inhibited on surfaces coated with bilayers of human serum albumin and the corresponding antibody. The critical amount of antibody required for inhibition was measured to 0.50 X 10(-8) micrograms/microns 2, corresponding to 1.6 X 10(6) antibody molecules per PMNL. Once immobilized on antigen-antibody coated surfaces, PMNL did not move chemotactically in response to formylmethionyl-leucyl-phenylalanine (fMLP). The receptor for fMLP appeared to be intact, however, since the cells responded metabolically to the chemotactic peptide.
Insights
Polymorphonuclear leucocytes (PMNL) movement is blocked on surfaces with antigen-antibody complexes. Even with intact formylmethionyl-leucyl-phenylalanine (fMLP) receptors, PMNL cannot move chemotactically when immobilized.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- Polymorphonuclear leucocytes (PMNL) are critical immune cells involved in host defense.
- Cellular locomotion is essential for PMNL function, including migration to sites of infection.
- Antigen-antibody complexes can influence immune cell behavior and signaling.
Purpose of the Study:
- To investigate the effect of surface-bound antigen-antibody complexes on PMNL locomotion.
- To determine the threshold concentration of antibody required to inhibit PMNL movement.
- To assess the chemotactic response of immobilized PMNL to formylmethionyl-leucyl-phenylalanine (fMLP).
Main Methods:
- Utilized ellipsometry, a surface-sensitive optical technique, to quantify surface-bound antibodies.
- Coated solid surfaces with bilayers of human serum albumin and specific antibodies.
- Observed and measured PMNL locomotion on these modified surfaces.
Main Results:
- PMNL locomotion was significantly inhibited on surfaces coated with antigen-antibody complexes.
- A critical antibody concentration of 0.50 X 10(-8) micrograms/microns 2 was identified for inhibition.
- Immobilized PMNL failed to exhibit chemotaxis towards fMLP, despite intact fMLP receptors.
- Metabolic responses to fMLP remained intact, indicating receptor functionality.
Conclusions:
- Surface-bound antigen-antibody complexes effectively inhibit PMNL locomotion.
- Specific antibody concentrations are critical for modulating PMNL migration.
- While PMNL receptors may be functional, immobilization on antigen-antibody complexes prevents directed movement.