title: Aberrant induction of regulatory activity of CD4+CD25+ T cells by dendritic cells in HIV-infected persons with amebic liver abscess.
abstract: To know why HIV-1-infected persons are particularly susceptible to amebic liver abscess (ALA), we investigated the role of CD4CD25 T cells in the susceptibility of HIV-1-infected persons to this disease. Herein we show, in early stage HIV-1-infected subjects, that CD4 T-cell responses to Entamoeba histolytica antigen (EhAg) were selectively impaired, especially in those with ALA. EhAg-specific CD4 T-cell responses were normalized by depletion of CD4CD25 cells or by addition of anti-cytotoxic T lymphocyte antigen 4 (CTLA4) antibody. Regulatory activity of CD4CD25 T cells to suppress the EhAg-specific CD4 T-cell response could be induced by EhAg-primed dendritic cells (DCs) in HIV-1-infected subjects, especially in those with ALA, but not in healthy controls. Exogenous Tat-incubated DCs derived from HIV-negative subjects also could upregulate CTLA4 expression on autologous CD4CD25 T cells and selectively suppress the EhAg-specific CD4 T-cell response. The results imply an interaction of the two pathogens: HIV-1, perhaps through the effect of Tat on DCs, may upregulate EhAg-specific regulatory T-cell activity to suppress T-cell response to E. histolytica, thus increasing the susceptibility to invasive amebiasis in even early-stage HIV-1-infected persons.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan. hsmaids@hotmail.com
authors.forename: Szu-Min
authors.initials: SM
authors.lastname: Hsieh
authors.forename: Mao-Yuan
authors.initials: MY
authors.lastname: Chen
authors.forename: Sung-Ching
authors.initials: SC
authors.lastname: Pan
authors.forename: Chien-Ching
authors.initials: CC
authors.lastname: Hung
authors.forename: Shan-Chwen
authors.initials: SC
authors.lastname: Chang
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D015658:HIV Infections / Q000150:complications / Q000276:immunology* / Q000473:pathology; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008101:Liver Abscess, Amebic / Q000150:complications / Q000276:immunology* / Q000473:pathology
chemical_list: D053645:Interleukin-2 Receptor alpha Subunit