Basophils infiltrate human gastric mucosa at sites of Helicobacter pylori infection, and exhibit chemotaxis in response to H. pylori-derived peptide Hp(2-20).
Basophils, which are normally confined to the circulation, can migrate to sites of allergic inflammation. Using the specific mAb, BB1, we detected basophil infiltration of the gastric mucosa of Helicobacter pylori-infected patients affected by moderate and severe gastritis. Basophils were not found in H. pylori-free individuals or in subjects with mild gastritis. The H. pylori-derived peptide, Hp(2-20), was a potent basophil chemoattractant in vitro, whereas the control peptide, Hp1, was ineffective. Basophils from peripheral blood of healthy volunteers expressed mRNA for the formyl peptide receptors, N-formyl-peptide receptor (FPR), FPR-like (FPRL)1, and FPRL2. Preincubation of basophils with FMLP or Hp(2-20) caused complete desensitization to a subsequent challenge with homologous stimulus. Incubation of basophils with a low concentration of FMLP, which binds with high affinity to FPR, but not to FPRL1 or FPRL2, did not affect the chemotactic response to Hp(2-20). In contrast, a high concentration of FMLP, which binds to FPRL1 and FPRL2, reduced the chemotactic response to Hp(2-20). The FPR antagonist, cyclosporin H, prevented chemotaxis induced by FMLP, but not by Hp(2-20). Hp(2-20) could be responsible, at least in part, for basophil infiltration of the gastric mucosa of H. pylori-infected patients presumably through the interaction with FPRL1 and FPRL2.
de Paulis
Amato
A
Department of Clinical Immunology and Allergy, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
Prevete
Nella
N
Fiorentino
Isabella
I
Walls
Andrew F
AF
Curto
Monica
M
Petraroli
Angelica
A
Castaldo
Vincenza
V
Ceppa
Paola
P
Fiocca
Roberto
R
Marone
Gianni
G
D001426:Bacterial Proteins / Q000494:pharmacology; D001491:Basophils / Q000502:physiology*; D001706:Biopsy; D016022:Case-Control Studies; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D005753:Gastric Mucosa / Q000166:cytology / Q000382:microbiology*; D005756:Gastritis / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori / Q000737:chemistry; D006801:Humans; D010446:Peptide Fragments / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D044042:Receptors, Formyl Peptide / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; D010446:Peptide Fragments; D012333:RNA, Messenger; D044042:Receptors, Formyl Peptide