Identification of lymphocytes extracted from bovine hemal nodes

Lymphocyte populations extracted and separated from hemal nodes (HN) and peripheral blood of 20 male healthy bovines were characterized by surface markers and the rosette-forming test. After treatment with FITC- or peroxidase-conjugated antibovine IgG, about 22% of cells from HN and peripheral blood showed superficial fluorescence (B cells) and about 13% were able to form "E rosettes" (T cells) with sheep erythrocytes pre-treated with neuraminidase. Nearly equal percentages were obtained from peripheral blood lymphocytes. On the basis of the data shown, we can conclude that the function of HN is, at least in healthy animals, analogous with that of lymph nodes. In this study we also used the SEM to evaluate the possibility of classifying the lymphoid cells as B and T lymphocytes on the basis of their surface morphology. Some authors have stated that B and T lymphocytes have a rough and smooth surface, respectively. In our experience, however, because of cells with a moderate number of surface microvilli exist, this method used on its own is not suitable for lymphocyte identification.