Cell surface markers on canine lymphocytes

Reference values for T and B lymphocytes were determined on lymphocytes from canine thymus, spleen, lymph node, bone marrow, and peripheral blood by use of erythrocyte (E) and erythrocyte-antibody-complement (EAC) rosette assays, plus a direct fluorescent technique for assay of surface immunoglobulins. Numbers of T lymphocytes, indicated by E rosette formation with human erythrocytes, ranged from a low of 1% in the thymus to 13% in the peripheral blood, whereas B-lymphocyte numbers ranged from 3% (thymus) to 41% (bone marrow) and from 6% (thymus) to 36% (bone marrow), as indicated by EAC rosette formation or presence of surface immunoglobulins respectively. Stimulation of peripheral blood lymphocytes with either phytohemagglutinin or concanavalin A increased the total number of E-rosetting cells two to threefold, whereas the number of EAC-rosetting cells decreased by half. Further, the percentage of cells bearing Fc receptors increased after phytohemagglutinin stimulation. These results indicate the E rosette technique can be used to identify and to monitor a population of canine T lymphocytes.