The separation of lymphocyte subpopulations with lectins

Wistaria floribunda agglutinin (WFA), Sophora japonica agglutinin (SJA) and Maclura pomifera lectin (MPL) were employed as immunofluorescent and leucoagglutinating reagents to study murine lymphocytes. WFA, which labels 90% of thymocytes, binds to only 57% of the splenocyte population. The latter subset corresponds to surface immunoglobulin bearing cells. Differential agglutination of splenocytes with this lectin results in the isolation of a WFA negative population which exhibits T-lymphocyte surface markers. The agglutinable splenocytes bind only 2.5 times more WFA than non-agglutinable cells suggesting that the preferential agglutination of B-splenocytes is due to a combination of reduced cell surface negative charge and increased number of lectin binding sites on these cells as compared to T-lymphocytes. Forty percent of splenocytes are positive for SJA and differential agglutination of splenocytes yields a population of SJA non-agglutinable cells that are not labeled by this lectin. The two populations fractionated by SJA are unrelated to T- and B-lymphocyte subsets. Differential agglutination of thymocytes by SJA yields a non-agglutinable group representing 42% of total thymocytes. Although the nature of the two thymocyte subsets discriminated by SJA remains unknown, this lectin appears useful in identifying and separating unique thymocyte and splenocyte populations.