Evaluation of two monkey species (Macaca mulatta and Macaca fascicularis) as possible models for human Helicobacter...

Endoscopic, histologic, and microbiologic evaluations of 21 cynomolgus and 34 rhesus monkeys for naturally occurring Helicobacter pylori infection were done. H. pylori was never isolated from any cynomolgus monkey, but was found in 12 rhesus monkeys. A general correlation existed between a positive culture and a gastric inflammatory response. Inoculation challenges were then undertaken. Four cynomolgus and five rhesus monkeys received two different H. pylori strains isolated from humans. Five rhesus monkeys received an isolate obtained from rhesus monkeys. Evaluation of the cynomolgus monkeys 7 and 14 days later revealed no H. pylori. Endoscopies of the rhesus monkeys were done 7, 14, 21, 28, and 56 days later. One rhesus monkey, which received the isolate from humans, became H. pylori positive at day 21 and remained positive through day 56. Restriction enzyme analysis of genomic DNA at day 56 revealed that the isolate was not identical to the challenge strain isolated from humans. All five rhesus monkeys that received the strain isolated from rhesus monkeys became H. pylori positive by day 14 and remained positive through day 56 Antral inflammation developed in all monkeys. Restriction enzyme analysis of genomic DNA on day 56 confirmed that four of five isolates were identical to the challenge strain isolated from rhesus monkeys. DNA hybridization documented homology between the challenge strains isolated from humans and rhesus monkeys plus those isolated at day 56. In this study, we showed that the rhesus monkey, if given a strain of H. pylori isolated from rhesus monkeys, develops a gastric infection with accompanying histological changes, making this model suitable for further development.