title: Lactobacillus paracasei subsp. paracasei B21060 suppresses human T-cell proliferation.
abstract: Recent studies have shown that probiotics are beneficial in T-cell-mediated inflammatory diseases. The molecular mechanism by which probiotics work remains elusive, but accumulating evidence indicates that probiotics can modulate immune cell responses. Since T cells express receptors for bacterial products or components, we examined whether different strains of lactobacilli directly regulate the functions of human T cells. CD4(+) T cells were isolated from blood and intestinal lamina propria (LP) of normal individuals and patients with inflammatory bowel disease (IBD). Mononuclear cells were also isolated from Peyer's patches. Cells were activated with anti-CD3/CD2/CD28 in the presence or absence of Lactobacillus paracasei subsp. paracasei B21060, L. paracasei subsp. paracasei F19, or L. casei subsp. casei DG. Cell proliferation and death, Foxp3, intracellular pH, and cytokine production were evaluated by flow cytometry. We showed that L. paracasei subsp. paracasei B21060 but neither L. paracasei subsp. paracasei F19 nor L. casei subsp. casei DG inhibited blood CD4(+) T-cell growth. This effect was associated with no change in cell survival, expression of Foxp3, or production of gamma interferon, interleukin-4 (IL-4), IL-5, and IL-10. L. paracasei subsp. paracasei B21060-mediated blockade of CD4(+) T-cell proliferation required a viable bacterium and was associated with decreased MCT-1 expression and low intracellular pH. L. paracasei subsp. paracasei B21060 also inhibited the growth of Peyer's patch mononuclear cells, normal lymphocytes, and IBD CD4(+) LP lymphocytes without affecting cytokine production. The data show that L. paracasei subsp. paracasei B21060 blocks T-cell growth, thus suggesting a mechanism by which these probiotics could interfere with T-cell-driven immune responses.
authors.affiliation: Dipartimento di Medicina Interna, Università Tor Vergata, Via Montpellier 1, 00133 Rome, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Peluso
authors.forename: Daniele
authors.initials: D
authors.lastname: Fina
authors.forename: Roberta
authors.initials: R
authors.lastname: Caruso
authors.forename: Carmine
authors.initials: C
authors.lastname: Stolfi
authors.forename: Flavio
authors.initials: F
authors.lastname: Caprioli
authors.forename: Massimo Claudio
authors.initials: MC
authors.lastname: Fantini
authors.forename: Giorgio
authors.initials: G
authors.lastname: Caspani
authors.forename: Enzo
authors.initials: E
authors.lastname: Grossi
authors.forename: Laura
authors.initials: L
authors.lastname: Di Iorio
authors.forename: Francesco Maria
authors.initials: FM
authors.lastname: Paone
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
mesh_terms: D017209:Apoptosis; D001769:Blood / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000096:biosynthesis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015212:Inflammatory Bowel Diseases / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology; D007778:Lactobacillus / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation; D027501:Monocarboxylic Acid Transporters / Q000096:biosynthesis; D010581:Peyer's Patches / Q000276:immunology; D019936:Probiotics; D027981:Symporters / Q000096:biosynthesis; D000099233:Monocarboxylate Transport Protein 1
chemical_list: D016207:Cytokines; D051858:Forkhead Transcription Factors; D027501:Monocarboxylic Acid Transporters; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1; C418974:FOXP3 protein, human