Host responses of guinea pigs infected with Helicobacter pylori were invest
igated. Passaged pylori colonised the stomach for up to 13 weeks after infe
ction, but after 1 month the number of bacteria fell sharply. Specific anti
bodies, predominantly of the IgG2 subtype, were present from week 3 onwards
. Antibodies to urease A and flagella were abundant. Severe inflammation of
the gastric mucosa and damage to the stomach epithelium was seen. Infiltra
tes of mononuclear cells and eosinophils were found near the parietal gland
s. As infection progressed, inflammation and tissue damage became more loca
lised and more variable between individual animals. These parameters can be
used as markers for colonisation of the stomach by H. pylori. (C) 2001 Pub
lished by Elsevier Science B.V. on behalf of the Federation of European Mic
robiological Societies.