Early-life longitudinal survey of peripheral blood lymphocyte subsets in Beagle dogs

A longitudinal study of peripheral blood lymphocyte subsets from 7 to 15 months of age was performed in Beagle dogs employing a multiparametric flow cytometry. The data were compared with data obtained from adult Beagle dogs that were housed in the same animal facilities and that were subjected to the same controls during the 34 weeks of the study. Absolute counts of total lymphocytes and CD3+ T, CD3+CD4+ Th and CD21+ B lymphocytes decreased during the entire 34 weeks period of the study in the young dogs group. The same was observed with regard to the percentage of CD3+CD4+ Th lymphocytes and the CD4/CD8 ratio, while the percentage of CD3+CD8+ Tc lymphocytes increased from 7 to 15 months of age. These age-related changes found in lymphocyte subsets distribution of young dogs led to level the absolute and relative values of adult dog lymphocytes. The observations of this longitudinal study illustrate the changes related to maturation of lymphocyte subsets that occur during early life in Beagle dogs.