Concanavalin A

Concanavalin A a mannose/glucose-binding lectin originally extracted from Jack beans (Canavalia ensiformis) [1].

Concanavalin A is a well-known T cell mitogen that can activate the immune system, recruit lymphocytes and elicit cytokine production [1]. In addition to its mitogenic activity, concanavalin A also can induce programmed cell death via mitochondria-mediated apoptosis and autophagy [2].

In human diploid fibroblasts, concanavalin A treatment at 50 μg/ml for 0.5, 1, 3, 5, and 24 h, increased the proportion of TUNEL⁺ ve cells in a time-dependent manner. After 3 h, concanavalin A reduced mitochondrial membrane potential in a subpopulation of apoptotic cells with smaller cell volume and with apoptotic nuclear morphology. The measurement of intracellular calcium ion concentration ([Ca²⁺]_i) showed that concanavalin A did not affect [Ca²⁺]_i viable cells but induced a progressive depletion of [Ca²⁺]_i with generation of calcium oscillations in apoptotic cells [2].

Concanavalin A (i.v., twice at 3-day intervals) at a dose of 20 mg/kg inhibited liver tumor formation in NOD/LtSz-PrkdcJ mice at 21 days after tumor inoculation, whereas the doses of 10 and 15 mg/kg showed no effect.

References:

[1]. Dwyer J M, Johnson C. The use of concanavalin A to study the immunoregulation of human T cells. Clinical and Experimental Immunology, 1981, 46(2): 237-249.

[2]. Kulkarni G V, Lee W, Seth A, et al. Role of mitochondrial membrane potential in concanavalin A-induced apoptosis in human fibroblasts. Experimental Cell Research, 1998, 245(1): 170-178.

[3]. Chang C P, Yang M C, Liu H S, et al. Concanavalin A induces autophagy in hepatoma cells and has a therapeutic effect in a murine in situ hepatoma model. Hepatology, 2007, 45(2): 286-296.