Concanavalin A-Induced Release of Skin-Reactive Factor from Lymphoid Cells

We have found that pretreatment of tuberculin-sensitive guinea pigs with the plant lectin concanavalin A suppresses their delayed hypersensitivity response (1). Concanavalin A also complexes with glycoproteins, and possibly glycolipids, at the surface of a variety of cells (2, 3), and with glycoproteins in body fluids (4, 5). In the case of lymphocytes, this binding initiates a series of reactions leading to blast transformation (3). The observation that phytohemagglutinin (another plant lectin) activates lymphocytes for the production of lymphotoxin (7–9) prompted us to further examine the effect of concanavalin A on normal lymphocytes. Concanavalin A was prepared by a minor modification (5) of the method of Agrawal and Goldstein (6). Axillary and inguinal lymph nodes and spleens were obtained from non-immune, randomly bred albino guinea pigs following exsanguination by cardiac puncture. The organs were diced and teased gently with mouse-toothed forceps in cold Hanks9 balanced salt solution and then filtered through sterile glass wool twice.