Construction of a novel Shigella live-vector strain co-expressing CS3 and LTB/STm of enterotoxigenic E.coli

Table 1 Bacteria and plasmids used in this research.

Strains and plasmids	Characteristics	Reference or source
E.coli
E44815	CS3, LT, ST	NICPBP
X6097	asd-	Dr. Roy CurissIII
S. flexneri
2457T		Dr. Wang
FWL01	(ipa-virg)-, smR, asd-ctxB+	Dr. Wang[3]
Plasmids
pASD21	ampR, asd	Dr. Wang[4]
pXZL01	ampR, LTB/STm	This lab[5]
pHCSIII	asd, CS3	This lab[5]
pZHY22	asd, LTB/STm,CS3	This lab[6]
pZCS02	asd, LTB/STm, CS3	This study

Table 2 Suckling mouse assay of ST.

Strain	G/C	Positive(+) Negative(-)	Suckling mice
ETEC 44815	0.126-0.04	+	5
FWL01	0.067-0.04	-	5
FWL01(pZCS02)	0.065-0.03	-	5

G/C is the ratio of gut weight to remaining carcass weight. A G/C ratio of ≥0.083 is positive.

Table 3 ELISA detection (A₄₉₂) of intestinal sIgA.

Intestinal sIgA	Anti-CS3	Anti-LTB	Anti-ST	Anti-LPS
Negative control	0.109±0.001	0.144±0.004	0.077±0.003	0.121±0.005
FWL01(pZHY22)	0.972±0.191	0.570±0.270	0.172±0.023	0.558±0.121
FWL01(pZCS02)	0.741±0.153	0.803±0.371	0.259±0.088	0.384±0.082

Samples were diluted at 1:50.