Enrichment of antitumor effector cells that are effective in vivo from spleen cells of tumor-bearing mice through the use of Dolichos biflorus lectin.

Spleen cells of X5563 tumor-bearing mice were fractionated with Dolichos biflorus lectin (DBA) into DBA+ (agglutinable with DBA) and DBA- (nonagglutinable with DBA) fractions. The DBA- cells showed antitumor activity specific for X5563 cells in vivo when injected into mice together with X5563 cells (Winn assay) or injected i.p. into mice previously inoculated s.c. with X5563 cells (adoptive transfer) with simultaneous administration of interleukin-2. Both DBA+ and DBA- cells have the cell surface phenotype of Lyt-1-2+, but only DBA- cells exhibit antitumor activity in vivo, while DBA+ cells have stronger cytolytic activity against X5563 cells in vitro than DBA- cells. This cell separation method involving the use of DBA is simple and gives reproducible results and high yields of viable cells.