Fractionation of mouse cytotoxic T cells by use of lectins.

Mouse cytotoxic T lymphocytes (CTLs), induced in vivo and in vitro in mixed-lymphocyte cultures, were fractionated into agglutinated and unagglutinated cells by use of various lectins. Cytolytic activity was enriched in the cell fraction agglutinated by various 2-acetamido-2-deoxy-alpha-D-galactopyranose-specific lectins, namely, Dolichos biflorus agglutinin (DBA), Helix pomatia agglutinin (HPA), and Phaseolus limensis agglutinin (LBA). Only a little cytolytic activity remained in the unagglutinated cell fraction. Furthermore, the relationship between the binding of lectins and the cytolytic activity in various CTL cell lines was investigated with a fluorescence-activated cell sorter, and high-rank correlation was found between the cytolytic activity of these CTL cell-lines and the binding of DBA or HPA to them, but weaker rank correlation in the cases of LBA and peanut agglutinin (PNA). DBA was found to bind to almost all cells of interleukin-2-dependent CTL cell-lines tested. Although the DBA-positive CTL cell-lines have strong cytolytic activity, the DBA-negative cells, which consist of a small proportion of the CTLs, also exhibited cytolytic activity. Thus, the major part of CTLs has binding sites for alpha-D-GalNAc-specific lectins, particularly for DBA, and this lectin is useful for the enrichment of CTLs. However, the binding sites for DBA cannot be regarded as an exclusive differential marker for CTLs.