title: Age-related changes in p56lck protein levels and phenotypic distribution of T lymphocytes in young rats.
abstract: p56lck is involved in the maturation of T-cells from double negative (DN) into double positive (DP) T-cells. The objective of this experiment was to determine changes in the levels of thymic and splenic T-cell p56lck using Western immunoblotting, along with the proportion and number ofT-cell subsets in thymus, spleen and blood using flow cytometry in growing Sprague-Dawley rats. Thymic p56lck levels were negatively correlated with age (r = - 0.42, p = 0.04) and positively correlated with age in the spleen (r = 0.50, p = 0.01). Nine-week-old rats had a higher percentage of thymic DN and CD8 cells with fewer DP cells compared to younger rats. There were minor differences in the proportions of T-cell subsets in the spleen and blood. T-cell numbers remained proportional to body weight in the lymphoid organs; however, the lower absolute number of T-cells in the younger rats might indicate that they are less able to respond to antigens.
authors.affiliation: Departments of Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Hosea
authors.forename: Edward S
authors.initials: ES
authors.lastname: Rector
authors.forename: Carla G
authors.initials: CG
authors.lastname: Taylor
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D008198:Lymph Nodes / Q000166:cytology / Q000378:metabolism; D018655:Lymphocyte Count; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D008297:Male; D009929:Organ Size; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism; D013154:Spleen / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)