title: B7 costimulatory ligand regulates development of the T-cell response to Cryptococcus neoformans.
abstract: The contribution of B7 molecules to the induction and maintenance of the T-cell response to the human pathogenic fungus Cryptococcus neoformans was investigated. T-cell activation by C. neoformans was regulated by B7 molecules. This costimulatory signal was necessary for initiation and maintenance of the T-cell response, through early and late requirements for B7-CD28 interaction. Blocking B7-2 inhibited the normal T-cell proliferative response. This inhibition was due, in part, to a reduced capability of T cells to produce interleukin-2 (IL-2). In contrast, the same T-cell population produced more interferon-gamma. Suppression of the normal lymphoproliferation and IL-2 secretion responses to encapsulated C. neoformans by antibodies to B7 was largely reversed by addition of the monoclonal antibody 2H1, that is reactive with the major capsular polysaccharide, glucuronoxylomannan. Overall, our data indicate that B7 molecules play a critical role in T-cell activation by C. neoformans and suggest that appropriate manipulation could drive T helper type 1 cell development.
authors.affiliation: Microbiology Section, Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Monari
authors.forename: T R
authors.initials: TR
authors.lastname: Kozel
authors.forename: A
authors.initials: A
authors.lastname: Casadevall
authors.forename: D
authors.initials: D
authors.lastname: Pietrella
authors.forename: B
authors.initials: B
authors.lastname: Palazzetti
authors.forename: A
authors.initials: A
authors.lastname: Vecchiarelli
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology*; D051940:B7-2 Antigen; D003455:Cryptococcus neoformans / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology; D011134:Polysaccharides / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D011134:Polysaccharides; C027478:glucuronoxylomannan; D007371:Interferon-gamma