Phaseolus limensis, commonly known as the lima bean, butter bean, sieva bean, double bean or Madagascar bean, is a legume grown for its edible seeds or beans.

Phaseolus limensis agglutinin (LBA) is isolated from lima bean seeds and purified by affinity chromatography. LBA is composed of 30,000 Da subunits, of which two are joined by a disulfide bond. Phaseolus limensis lectin (LBL) consists of at least three molecular components: Component III (LBL4), component II (LBL,8 a dimeric form of component III), and component I, a higher molecular weight form. These components differ in their mitogenic activity toward human lymphocytes with component II (LBL8) showing the highest activity.

Each subunit contains a cysteine residue which is required for both its carbohydrate- and metal-ion-binding activities. It has a carbohydrate specificity of terminal GalNAc(1,3)Gal that elutes with N-acetylgalactosamine. LBA agglutinates blood group A erythrocytes.