BOVINE LYMPHOID SYSTEM - BINDING AND STIMULATION OF PERIPHERAL-BLOOD LYMPHOCYTES BY LECTINS

The ability of 11 different lectins to stimulate DNA synthesis was tested in bovine peripheral blood lymphocytes, using a wide range of experimental conditions. Five of the 6 lectins which induced DNA synthesis (concanavalin [Con] A, succinyl-concanavalin A, phytohemagglutinin M, pokeweed mitogen and lipopolysaccharide) did so under conditions similar to those optimal for stimulation of murine lymphocytes. The other lectin (peanut agglutinin) stimulated normal bovine lymphocytes whereas it did not stimulate normal mouse, rat, guinea pig or human lymphocytes. The binding of 5 different lectins to bovine peripheral blood lymphocytes was measured by fluorescence microscopy. Four of the lectins bound to various proportions of cells. Double labeling experiments using a rhodamine-labeled goat anti-bovine immunoglobulin [Ig] reagent and fluorescein-labeled lectins showed that peanut agglutinin and soybean agglutinin bound to lymphocyte populations which were negative for surface Ig. The majority of lymphocytes negative for surface Ig bound peanut agglutinin, indicating that this lectin may bind specifically to bovine T [thymus-derived] lymphocytes.