Table 1 Glycine-induced MVs (vector control) and CPS14+MVs.

From: A highly immunogenic vaccine platform against encapsulated pathogens using chimeric probiotic Escherichia coli membrane vesicles

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. *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. *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. *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. *4: Shown are results (mean ± SD) obtained from glycine-induced MVs (vector control, n = 3) and glycine-induced CPS14+MVs (n = 5).
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