Concanavalin A from Canavalia ensiformis (Jack bean)

Concanavalin A from Canavalia ensiformis (jack bean) has been used:

• to induce spleen blastogenesis
• to generate ConA blast targets from B6 and lpr spleen cells
• to stimulate splenic lymphocytes from estrogen-and placebo-treated mice

Con A is not blood group specific but has an affinity for terminal α-D-mannosyl and α-D-glucosyl residues. Ca²⁺ and Mn²⁺ ions are required for activity. Con A dissociates into dimers at pH 5.6 or below. Between pH 5.8 and pH 7.0, Con A exists as a tetramer; above pH 7.0 higher aggregates are formed. Con A exhibits mitogenic activity which is dependent on its degree of aggregation. Succinylation results in an active dimeric form which remains a dimer above pH 5.6.

Where reported, agglutination activity is expressed in μg/ml and is determined from serial dilutions in phosphate buffered saline, pH 6.8, containing Ca²⁺ and Mn²⁺ of a 1 mg per mL solution. This activity is the lowest concentration to agglutinate a 2% suspension of human erythrocytes after 1 hr incubation at 25 °C.