title: Naturally activated CD4+ T cells are highly enriched for cytokine-producing cells.
abstract: Most T cells in a normal non-immunized individual are in a resting state. However, a small proportion of splenic T cells are large activated cells both in specific pathogen-free and antigen-free mice. To further elucidate the effector functions associated with these "naturally" activated CD4+ T cells, we have characterized the expression of various membrane markers, cytokine production and T helper activity by these cells. We show that naturally activated CD4+ T cells express activation markers and contain tenfold higher proportions of cells producing IL-4, IL-10 and IFN-gamma as compared to small CD4+ T cells. Despite the high proportion of IFN-gamma producers, naturally activated CD4+ T cells still induce B cell proliferation and differentiation. These results are discussed in the context of normal physiological autoreactivity.
authors.affiliation: Immunology Group, Department of Cell and Molecular Biology, University of Lund, Sweden. lukas.cederbom@immuno.lu.se
authors.forename: L
authors.initials: L
authors.lastname: Cederbom
authors.forename: A
authors.initials: A
authors.lastname: Bandeira
authors.forename: A
authors.initials: A
authors.lastname: Coutinho
authors.forename: F
authors.initials: F
authors.lastname: Ivars
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D018960:Hyaluronan Receptors; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism
chemical_list: D016207:Cytokines; D018960:Hyaluronan Receptors