title: Heterologous immunity and homeostatic proliferation as barriers to tolerance.
abstract: The different threshold of activation for memory T cells compared to that of naïve T cells makes them resistant to immunomodulation, thus representing a barrier to tolerance. Recently it has been demonstrated that homeostatic proliferation and heterologous immunity represent two naturally occurring and distinct processes that can generate memory T cells. Homeostatic proliferation refers to the process by which, in a lymphodeficient host, normal T cells 'spontaneously' proliferate in response to self-MHC-peptide complexes. Heterologous immunity refers to a process in which a response to one or more infectious agents generates effector/memory T cells with cross-reactive specificities. Recent new studies have defined the importance of these processes in transplantation models and implicated strategies to induce transplantation tolerance.
authors.affiliation: University of Pennsylvania, 700 Clinical Research Building, 415 Curie Boulevard, Philadelphia 19104-6144, USA.
authors.forename: Devon K
authors.initials: DK
authors.lastname: Taylor
authors.forename: David
authors.initials: D
authors.lastname: Neujahr
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Turka
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000276:immunology; D049109:Cell Proliferation; D006084:Graft Rejection / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D007156:Immunologic Memory; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D001324:Autoantigens