Stimulation of human peripheral lymphocytes and induction of interleukin 2 production by a lectin from the gonad of the sea hare, Aplysia fasciata.

The lectin from gonads of the sea hare, Aplysia fasciata, which reacts with D-galacturonic acid and D-galactose derivatives, was purified by affinity chromatography on Sepharose 4B. The purified lectin was shown to stimulate human peripheral blood lymphocytes and to induce interleukin 2 production like PHA. These activities were specifically inhibited by D-galactose and neutralized galacturonic acid (not by glucuronic acid). The rate of lymphocyte proliferation was similar at 72 and 96 hours in culture. The main stimulation was observed in the T lymphocyte population obtained by rosette formation with sheep red blood cells.