title: The effects of age and cytomegalovirus on markers of inflammation and lymphocyte populations in captive baboons.
abstract: The human immune system undergoes age-related changes that can lead to increased disease susceptibility. Using the baboon as a model for human immune system aging, we examined age-related changes in relative and absolute numbers of T cell subpopulations, cytomegalovirus (CMV) titer and markers of inflammation. In addition, the effect of gender, social status and peer group on lymphocyte subpopulations was determined. Relative and absolute numbers of total lymphocytes (CD3+), T helper cells (CD4+), and cytotoxic T cells (CD8+) increased with age. The proportion of naïve T cells (CD45RA+) decreased, while the total number of cells negative for the co-stimulatory receptor, CD28 (CD28-) increased in an age-dependent manner. Furthermore, CMV titers were negatively correlated with the number of naive CD4+ cells. IL-6 and cortisol concentration were also negatively associated with T cell subpopulations. Additionally, socially dominant baboons exhibited decreases in naïve CD4+ and CD8+ cells (by 65% and 52%, respectively) compared to subordinate animals. These results suggest that factors such as CMV exposure and inflammation may contribute to the age-related decline in immune health and indicate that factors like social status should be considered when studying immunosenescence in animal models.
authors.affiliation: Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America.
authors.forename: Erin L
authors.initials: EL
authors.lastname: Willis
authors.affiliation: Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America.
authors.forename: Richard
authors.initials: R
authors.lastname: Eberle
authors.affiliation: Department of Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America.
authors.forename: Roman F
authors.initials: RF
authors.lastname: Wolf
authors.affiliation: Department of Comparative Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America.
authors.forename: Gary L
authors.initials: GL
authors.lastname: White
authors.affiliation: Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America.
authors.forename: Dianne
authors.initials: D
authors.lastname: McFarlane
mesh_terms: D000367:Age Factors; D000375:Aging / Q000097:blood / Q000276:immunology* / Q000473:pathology; D000818:Animals; D015415:Biomarkers / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D003587:Cytomegalovirus; D003586:Cytomegalovirus Infections / Q000097:blood / Q000276:immunology* / Q000473:pathology; D006854:Hydrocortisone / Q000097:blood; D007107:Immune System / Q000276:immunology / Q000473:pathology; D007249:Inflammation / Q000097:blood / Q000276:immunology* / Q000473:pathology; D015850:Interleukin-6 / Q000097:blood; D010215:Papio; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D006854:Hydrocortisone