title: Human intestinal lamina propria lymphocytes are naturally permissive to HIV-1 infection.
abstract: The presence of HIV-1 in the intestinal mucosa of AIDS patients has been reported and human intestinal lamina propria lymphocytes (LPL) have been proposed as important targets for HIV-1 infection. However, little information is available concerning the permissiveness of human intestinal CD4+ T lymphocytes to HIV-1 infection. Here, we show that human LPL, in contrast to autologous peripheral blood lymphocytes (PBL), are permissive to both X4 T-tropic and R5 M-tropic strains of HIV-1, as well as to clinical isolates, in the absence of exogenous stimuli. Flow cytometry showed that the vast majority of T LPL were CD45RO+ and CD69+, and that CD4+ T LPL highly expressed CC chemokine receptor 5 (CCR5) as compared to PBL, while CX chemokine receptor 4 was equally expressed on LPL and PBL. Exogenous RANTES and macrophage inflammatory protein-1alpha (natural CCR5 ligands) virtually abolished the entry of the R5 M-tropic strain HIV-1 into human LPL. Thus, we infer that human intestinal CD4+ T lymphocytes are naturally susceptible to HIV-1 infection, due to their physiological state of activation and to marked expression of HIV-1 coreceptors, independently of the route of primary (either mucosal or parental) infection and the shifts of the virus phenotype occurring during the course of AIDS.
authors.affiliation: Laboratory of Virology, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Lapenta
authors.forename: M
authors.initials: M
authors.lastname: Boirivant
authors.forename: M
authors.initials: M
authors.lastname: Marini
authors.forename: S M
authors.initials: SM
authors.lastname: Santini
authors.forename: M
authors.initials: M
authors.lastname: Logozzi
authors.forename: M
authors.initials: M
authors.lastname: Viora
authors.forename: F
authors.initials: F
authors.lastname: Belardelli
authors.forename: S
authors.initials: S
authors.lastname: Fais
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D002478:Cells, Cultured; D054407:Chemokine CCL4; D018946:Chemokine CCL5 / Q000494:pharmacology; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007422:Intestines / Q000276:immunology*; D019402:Macrophage Inflammatory Proteins / Q000494:pharmacology; D019713:Receptors, CCR5 / Q000032:analysis; D019718:Receptors, CXCR4 / Q000032:analysis
chemical_list: D054407:Chemokine CCL4; D018946:Chemokine CCL5; D019402:Macrophage Inflammatory Proteins; D019713:Receptors, CCR5; D019718:Receptors, CXCR4