Subcellular Distribution of Sphingomyelin in Granules and Light Membranes (secretory vesicles/plasma membranes)
| . | MPO . | Lactoferrin . | Gelatinase . | Latent AP . | HLA . | SM . |
|---|---|---|---|---|---|---|
| Azurophil granules | 77.4 ± 2.1 | 7.1 ± 0.7 | 1.4 ± 0.2 | 0 | 0 | 23.7 ± 0.3 |
| Specific granules | 15.4 ± 0.9 | 82.2 ± 1.2 | 41.1 ± 7.1 | 0 | 4.5 ± 0.8 | 23.5 ± 1.4 |
| Gelatinase granules | 4.8 ± 0.5 | 7.8 ± 0.5 | 48.2 ± 5.0 | 15.9 ± 0.2 | 14.7 ± 8.0 | 24.1 ± 0.8 |
| Light membranes | 2.1 ± 0.7 | 1.3 ± 0 | 9.2 ± 2.1 | 81.5 ± 0.3 | 80.8 ± 8.4 | 28.7 ± 2.0 |
| Cytosol | 0.3 ± 0.2 | 1.6 ± 1.8 | 0.1 ± 0.1 | 2.6 ± 0.1 | 0 | 0 |
| . | MPO . | Lactoferrin . | Gelatinase . | Latent AP . | HLA . | SM . |
|---|---|---|---|---|---|---|
| Azurophil granules | 77.4 ± 2.1 | 7.1 ± 0.7 | 1.4 ± 0.2 | 0 | 0 | 23.7 ± 0.3 |
| Specific granules | 15.4 ± 0.9 | 82.2 ± 1.2 | 41.1 ± 7.1 | 0 | 4.5 ± 0.8 | 23.5 ± 1.4 |
| Gelatinase granules | 4.8 ± 0.5 | 7.8 ± 0.5 | 48.2 ± 5.0 | 15.9 ± 0.2 | 14.7 ± 8.0 | 24.1 ± 0.8 |
| Light membranes | 2.1 ± 0.7 | 1.3 ± 0 | 9.2 ± 2.1 | 81.5 ± 0.3 | 80.8 ± 8.4 | 28.7 ± 2.0 |
| Cytosol | 0.3 ± 0.2 | 1.6 ± 1.8 | 0.1 ± 0.1 | 2.6 ± 0.1 | 0 | 0 |
Isolated, resting PMNs were subjected to fractionation on three-layer gradients as described in Experimental Procedures and in the legend to Fig 1. The following fractions were pooled: Fractions 1-7 (azurophil granules), fractions 8-14 (specific granules), fractions 15-19 (gelatinase granules), and fractions 20-35 (light membranes). Percoll was removed by ultracentrifugation, and the biological material washed once in PBS. The supernatant of fractions 20-35 was decanted after ultracentrifugation (cytosol). Samples were assayed for myeloperoxidase (MPO), lactoferrin, gelatinase, latent AP, HLA, and sphingomyelin (SM) as described. Numbers are average of three experiments and expressed as the amount measured in a sample in percentage of the total amount measured (± SD).