Helicobacter pylori vacA genotype is a predominant determinant of immune response to Helicobacter pylori CagA

Table 1 Characteristics of patients with active Helicobacter pylori infection regarding patient’s CagA-IgG status n (%)

	Total	H. pylori + CagA-IgG-	H. pylori + CagA-IgG+	P value
Total	99	69 (69.7)	30 (30.3)
Gender				NS
Female	72	51 (73.9)	21 (70)
Male	27	18 (26.1)	9 (30)
Age
mean ± SD	54.1 ± 14.1	53.7 ± 13.7	55.1 ± 15.0	NS
H. pylori status
Anti-H.pylori-IgG+	93	64 (92.8)	29 (96.7)	NS
Anti-CagA-IgG+	30	-	30 (100)
mean CagA-IgG EIU		1.5 ± 1.7	39.6.5 ± 31.1	< 0.0001
Culture+	99	69 (100)	30 (100)	NS
Histology+	79	55 (79.7)	24 (80)	NS
Clinical phenotype
Chronic active Gastritis (any severity)	92	63 (91.3)	29 (96.7)	NS
Chronic non-active Gastritis (grade > 2)1	7	6 (8.7)	1 (3.3)	NS
Corpus predominant gastritis	5	0 (0)	5 (16.7)	0.0020
Antrum-/pangastritis	87	63 (91.3)	24 (80)	NS
Chronic atrophic gastritis (any severity)	46	25 (36.2)	21 (70)	0.0023
Chronic atrophic gastritis (> 2/3)1	28	14 (20.3)	14 (46.7)	0.014
Intestinal metaplasia (any)	23	12 (17.4)	11 (36.7)	0.068
Gastric cancer	6	2 (2.9)	4 (13.3)	0.056
PUD or MALT-Lymphoma (any)	5	4 (5.8)	1 (3.3)	NS
Normal mucosa (no PMNs and ≤ 1 chronicity)1	4	4 (5.8)	0 (0)	NS

¹Score based on the Sydney classification. NS: Not significant, P > 0.05. PUD: Peptic ulcer disease; PMNs: Polymophonuclear neutrophils.

Table 2 Characteristics of Helicobacter pylori strains in CagA IgG dependent status of the host n (%)

	Total	H. pylori +CagA-IgG-	H. pylori +CagA-IgG+	P value
Total	99	69 (69.7)	30 (30.3)
cagA gene1				NS
Positive	93	63 (91.3)	30 (100)
Negative	6	6 (8.7)	0
cagA mRNA2	87	60	27	< 0.0001
Positive	61	34 (56.7)	27 (100)
Negative	26	26 (43.3)	0 (0)
EPIYA motifs				NS
Negative	5	5 (7.2)	0
AB	4	2 (2.9)	2 (6.7)
ABC	33	21 (30.4)	12 (40)
ABCC	7	6 (8.7)	1 (3.3)
ABCCC	2	1 (14.5)	1 (3.3)
Mixed	48	34 (49.3)	14 (46.7)
VacA-IgG1,3		8 (13.1)	5 (18.5)	NS
vacA subtype1
s1	65	35 (50.7)	30 (100)	< 0.0001
s2	34	34 (49.3)	0
m1	42	19 (27.5)	23 (76.7)	< 0.0001
m2	57	50 (72.5)	7 (23.3)
s1m1	42	19 (27.5)	23 (76.7)	< 0.0001
s1m2	23	16 (23.2)	7 (23.3)
s2m2	34	34 (49.3)	0

¹Six patients with evidence for different/mixed cagA⁺/cagA^- or vacA strains in corpus and antrum have been included to the potentially more pathogenic group for simplicity;

²RNA analyses were possible only in 87 patients/strains;

³Eighty-eight samples were available for VacA-IgG analyses. NS: Not significant, P > 0.05.

Table 3 Validation of CagA expression and cellular translocation in AGS cells

	Strain characterization				In vitro
ID	cagA DNA	cagA RNA	CagA-IgG	vacA	H.pylori CagA	AGS + H.pylori CagA	AGS + H.pylori p-CagA
BCM300	+	+		s1m1	+	+	+
117	+	+	+	s1m1	+	+	+
6	+	+	-	s1m1	+	+	+
255	+	+	-	s1m1	+	+	+
13/1	+	+	+	s1m1	+	+	-
46	+	+	-	s1m1	+	+	-
89	+	+	-	s1m2	+	+	-
424	+	+	+	s1m2	-	-	-
21	+	-	-	s1m1	-	-	-
321	+	+	-	s2m2	-	-	-
374	+	+	-	s2m2	-	-	-
342	+	-	-	s2m2	-	-	-
314	-	-	-	s1m2	-	-	-
450	-	-	-	s1m2	-	-	-

AGS cells co-cultivated in similar conditions without Helicobacter pylori were considered as negative control. Strains were characterized based on cagA DNA/RNA/cagA-IgG seropositivity of the host and vacA polymorphism. “+”: positive and “-“: negative expression. p-CagA and CagA: Phosphorylated p-CagA and total CagA protein expression in vitro.