Augmentation of Helicobacter pylori urease activity by its specific IgG antibody: implications for bacterial colonization enhancement.
Gastric colonization of Helicobacter pylori (H. pylori) occurs in a very early age via infected mothers having H. pylori-specific IgG antibodies that would be transplacentally transferred to infants. In addition, H. pylori urease-specific IgG was associated with chronic gastric atrophy and post-immunization gastritis is usually correlated with a strong local IgG response. These findings indicate that H. pylori-specific IgG antibodies, in particular its urease-specific IgG, may induce unfavorable influence on host resistance against H. pylori. Here, we show that we have found a unique H. pylori urease-specific IgG monoclonal antibody (MAb), termed S3, recognizing the conformational structure of the small subunit Ure-A, which enhanced the urease enzymatic activity. Such enhancement of the H. pylori urease activity induced by 1 microg of S3 was almost completely cancelled by simultaneously added the same amount of L2 MAb, which has a strong and specific inhibitory activity against H. pylori urease and recognizes a liner epitope of 8-mer peptide (F8: SIKEDVQF) within its large subunit Ure-B (Infect. Immun. 69: 6597, 2001). Intravenous pre-administration of purified S3 into BALB/c mice showed significant augmentation for gastric colonization with the susceptible strain Sydney Strain-1 (SS-1). To our knowledge, this is the first demonstration that a H. pylori urease-specific IgG MAb induced an augmentation of their gastric colonization in vivo.
Iizumi
Tadasu
T
Department of Microbiology and Immunology, Third Department of Internal Medicine, Nippon Medical School, Tokyo 113-8602, Japan.
Yamanishi
Shingo
S
Kumagai
Yoshihiro
Y
Nagata
Kumiko
K
Kamiya
Shigeru
S
Hirota
Kaoru
K
Watanabe
Eri
E
Sakamoto
Choitsu
C
Takahashi
Hidemi
H
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000008:administration & dosage; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000235:genetics; D018604:Epitope Mapping; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology / Q000382:microbiology; D005756:Gastritis / Q000276:immunology / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology / Q000382:microbiology; D016480:Helicobacter pylori / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D007074:Immunoglobulin G / Q000008:administration & dosage; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D014510:Urease / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D014510:Urease