title: Helicobacter pylori induces apoptosis of T- and B-cell lines and translocates mitochondrial apoptosis-inducing factor to nucleus.
abstract: Immune cell apoptosis may play a role in human persistent Helicobacter pylori infection. We planned to study the apoptosis of T and B cells by H. pylori strains. T (Jurkat) and B (Raji) cell lines were co-cultured with cagA-positive H. pylori strains carrying different vacA genotypes (s1a/m1, s1a/m2, and s2/m2). Apoptosis was detected by microscopy, DNA fragmentation assay, and flow cytometry. Apoptosis-inducing factor (AIF) transfer from mitochondria to nucleus was studied by immunoblot analysis. Apoptosis of T and B cells was significantly higher in H. pylori-infected cells than in uninfected controls (s1a/m1 80%, s1a/m2 78%, s2m2 69% vs. control 16% for T cells, P < 0.001; s1 a/m1 78%, s1a/m2 73%, s2m2 62% vs. control 24% for B cells, P < 0.001 by flow cytometry) with no difference among the genotypes. AIF transfer from mitochondria to nucleus was demonstrated in both apoptotic cell lines. Thus, H. pylori induces apoptosis in T- and B-cell lines and translocates AIF. T and B cells deletion through apoptosis may explain the persistence of H. pylori infection; its role in pathogenesis needs further research.
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226 014, India.
authors.forename: Manisha
authors.initials: M
authors.lastname: Singh
authors.forename: Kashi N
authors.initials: KN
authors.lastname: Prasad
authors.forename: Ashish
authors.initials: A
authors.lastname: Saxena
authors.forename: Surender K
authors.initials: SK
authors.lastname: Yachha
mesh_terms: D021581:Active Transport, Cell Nucleus; D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000378:metabolism*; D001402:B-Lymphocytes / Q000502:physiology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D005838:Genotype; D016480:Helicobacter pylori / Q000235:genetics / Q000502:physiology*; D006801:Humans; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D051033:Apoptosis Inducing Factor