Lymphocyte subsets and expression of differentiation markers in blood and lymphoid organs of rhesus monkeys.

Rhesus macaques are invaluable experimental animals in biomedical research. Using three color flow cytometry, we screened anti-human antibodies for crossreactivity with macaque cells in order to determine the distribution of functionally important lymphocyte subsets in blood, lymph nodes (LN), and spleen. NK-cells are almost completely absent in LN. The percentage of B-cells expressing CD80, CD86, and the level of expression of CD20 is higher in blood than in LN. In contrast, a higher proportion of B-cells in LN stains positive for CD21 and CD35. Whereas the number of CD29hi expressing T-cells is lower, CD69 is expressed on more T-cells in LN than in blood. About one-third of CD8+ T-cells in blood are CD28-, a subset with a unique pattern of antigen expression which cannot be found in LN. In contrast to humans, a relatively high proportion of T-cells in blood also express the co-stimulatory molecules CD80 and CD86. With increasing age, the proportion of B-cells in blood declines, whereas the percentage of T-cells rises. In addition, the proportion of CD29hi expressing T-cells increases among both the CD4+ and CD8+ subsets.