title: Antigen-specific CD4 T cell clonal expansion and differentiation in the aged lymphoid microenvironment. I. The primary T cell response is unaffected.
abstract: Aging is associated with changes in the immune system that lead to decreased immunity in the elderly. Prior studies from humans and mice have shown that aged T cells exhibit numerous defects, including decreased proliferation following in vitro stimulation, suggesting that intrinsic defects exist within aged T cells, leading to defective T cell activation and clonal expansion. In vivo, however, cellular and soluble factors in the lymphoid microenvironment influence T cell function. To investigate the effects of the aged lymphoid microenvironment on T cell function, we monitored the immune response of CD4 T cells from DO11.10 TCR transgenic mice following adoptive transfer into young and aged hosts. After immunization with specific antigen similar rates of donor DO11.10 T cell division were observed in the two host types. However, at the peak of the response, greater numbers of DO11.10 T cells were found in the aged hosts. Regardless of the age of the host, the donor DO11.10 T cell population differentiated into functional effector cells. Despite the increased CD4 T cell growth in aged hosts, similar numbers of memory DO11.10 T cells were found in young and in aged hosts. As CD4 T cell clonal expansion and differentiation is not impaired in the aged microenvironment, our data suggest that diminished T cell immunity during aging is largely due to intrinsic T cell defects, rather than to extrinsic influences associated with the aged lymphoid microenvironment.
authors.affiliation: The Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY 12201, USA.
authors.forename: James N
authors.initials: JN
authors.lastname: Mittler
authors.forename: William T
authors.initials: WT
authors.lastname: Lee
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D000939:Epitopes; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic / Q000235:genetics; D010047:Ovalbumin / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics
chemical_list: D000939:Epitopes; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D010047:Ovalbumin