Table 1.
Glycine-induced MVs (vector control) and CPS14+MVs.
| Numerical information | MVs (vector control) | CPS14+MVs |
|---|---|---|
| Yield (mg, protein equivalent/1 L culture supernatant)*1 | 8.23 ± 3.48 | 24.34 ± 13.46 |
| Number of MVs (particles × 106/ng, protein equivalent)*2 | 2.11 ± 0.159 | 2.38 ± 0.867 |
| Diameter (nm)*2 | 60.5 ± 0.635 | 63.5 ± 2.03 |
| Lipid A activity, protein equivalent (EU × 103/ng)*3 | Not determined | 10.2 ± 6.82 |
| Pneumococcal CPS14 amount (ag/single particle)*4 | 0.00 ± 0.00 | 5.54 ± 2.56 |
| E. coli O6 amount (unit [O6]/single particle) *1 | 0.196 ± 0.0372 | 0.0372 ± 0.0221 |
*1: Shown are results (mean ± SD) obtained from glycine-induced MVs (vector control, n = 3) and glycine-induced CPS14+MVs (n = 5). A statistically significant difference was detected between the groups (p < 0.05). The yields of both MVs after induction with glycine was ~20- and 60-fold, respectively, higher than that of the non-induced EcNΔflhD strain without any vector (0.406 ± 0.0868 mg, protein equivalent, per one-liter culture supernatant, mean ± SD, n = 3).
*2: Shown are results (mean ± SD) obtained from glycine-induced MVs (vector control, n = 3) and glycine-induced CPS14+MVs (n = 5). There was no significant difference between the groups. Note: NanoFCM used in the present study is a state-of-the-art flow cytometry system for nanoparticles, though has a technical limitation making it unable to detect particles smaller than 40 nm in diameter. Therefore, the number of smaller particles is not included.
*3: Lipid A activity was determined as endotoxin unit (EU) using limulus assay with LPS of E. coli O111:B4 as the standard. Shown are results (mean ± SD) obtained from glycine-induced CPS14+MVs isolated from EcNΔflhD/pNLP80 (n = 3). Activity of the glycine-induced MVs (vector control) was not examined. On the other hand, the activity level of glycine-induced CPS14+MVs was determined to be ~3-fold lower than that of non-induced MVs isolated from the EcNΔflhD strain without a vector (32.58 ± 12.67 [x103 EU/ng], n = 3). There was a significant difference between the groups (P < 0.05).
*4: Shown are results (mean ± SD) obtained from glycine-induced MVs (vector control, n = 3) and glycine-induced CPS14+MVs (n = 5).