A predominant Th1 type of immune response is induced early during acute Helicobacter pylori infection in rhesus macaques

Background and Aims: The immune response of gastric T cells during acute Helicobacter pylori infection has not been previously characterized. The aim of this study was to delineate the phenotypic and functional responses of gastric T cells during acute H. pylori infection of rhesus macaques. Methods: Four monkeys were experimentally infected with H. pylori. Gastric biopsy specimens and peripheral blood samples were obtained 1 and 12 weeks after inoculation. Samples from 3 animals uninfected with H. pylori served as controls. The immunophenotypic changes and functional potential of CD4⁺ and CD8⁺ T cells in gastric mucosa and peripheral blood to produce cytokines (interleukin [IL]-2, IL-4, IL-13, interferon [IFN]-γ, MIP1β, and tumor necrosis factor [TNF]-α) were determined at a single cell level using flow cytometry. Results: An increase in CD4⁺ T cells occurred in the gastric mucosa during acute H. pylori infection as early as I week after infection. Acute infection was characterized by a predominantly T helper (Th)1 (IL-2 and IFN-γ) and proinflammatory (TNF-α and MIP-1β) type of cytokine response and the absence of a Th2 type of response. Conclusions: A predominant Th1 type response was induced early during acute H. pylori infection and may contribute to the development of gastric disease.