title: IL-4-producing CD8+ T cells with a CD62L++(bright) phenotype accumulate in a subgroup of older adults and are associated with the maintenance of intact humoral immunity in old age.
abstract: An increased production of proinflammatory cytokines occurs in a high percentage of elderly persons and is associated with an impaired humoral immune response. However, high IL-4 production has also been observed in old age. We now demonstrate an IL-4-producing subpopulation of CD8+ T cells in a subgroup of healthy older adults. This T cell subset is substantial in size and has a characteristic phenotype expressing CD45RO, CD28, CD62L, and CD25. IL-4-producing CD8+ T cells produce large amounts of IL-2 but not IFN-gamma or perforin, and these cells do not have a regulatory suppressive effect on other T cells. In vivo IL-4-producing CD8+ T cells can be stably detected over a year. When put into culture they also have a stable cytokine production pattern but fail to produce perforin even in the presence of IL-12. This special T cell type does not occur in persons under the age of 40, but is present in 36% of the persons >60 years of age. In this age group, IL-4-producing CD8+ T cells are more frequent in persons who are still capable of raising a humoral immune response following immunization than in others who fail to produce protective Abs after vaccination. Our results suggest that CD8+ T cells with a CD62L++(bright) phenotype accumulate in a subgroup of older adults. Due to their phenotype that enables them to migrate into lymphoid tissues and to their capacity to produce IL-4, these cells may counterbalance the overproduction of proinflammatory cytokines in old age.
authors.affiliation: Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria.
authors.forename: Susanne
authors.initials: S
authors.lastname: Schwaiger
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Wolf
authors.forename: Peter
authors.initials: P
authors.lastname: Robatscher
authors.forename: Brigitte
authors.initials: B
authors.lastname: Jenewein
authors.forename: Beatrix
authors.initials: B
authors.lastname: Grubeck-Loebenstein
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology*; D000914:Antibodies, Viral / Q000096:biosynthesis*; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism* / Q000821:virology; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000032:analysis / Q000096:biosynthesis*; D019041:L-Selectin / Q000096:biosynthesis*; D017493:Leukocyte Common Antigens / Q000096:biosynthesis; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D007959:Lymphocyte Culture Test, Mixed; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D008875:Middle Aged; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis; D016176:T-Lymphocyte Subsets / Q000737:chemistry / Q000276:immunology / Q000378:metabolism / Q000821:virology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D011948:Receptors, Antigen, T-Cell; D054353:Perforin; D019041:L-Selectin; D015847:Interleukin-4; D007371:Interferon-gamma; D017493:Leukocyte Common Antigens