Streptavidin is a protein derived from the bacterium Streptomyces avidinii, with a molecular weight of approximately 60 kDa as a homologous tetramer. Streptavidin is known for its strong affinity to bind with biotin (Vitamin H or B7). The interaction between biotin and streptavidin is one of the strongest non-covalent interactions known in nature, with a dissociation constant (KD) of approximately 0.01 picomolar. Streptavidin also has immunosuppressive properties.

与对照组相比，链霉亲和素（2-200 μg/mL）显著抑制 Lewis T细胞向WF的增殖，抑制率为76%-83%[1]。 在Western blot或ELISA中，0.1-1 µg/ml的浓度就足够。 在免疫沉淀中，可以使用1-10 µg/ml的浓度。

链霉亲和素治疗剂量小于60毫克/千克，疗程少于10天的情况下，在心脏移植后21至40天内可完全恢复。然而，增加剂量（超过60毫克/千克）或延长链霉亲和素的给药时间会导致严重的体重减轻和动物死亡，这表明链霉亲和素的毒性是剂量依赖性的。[2]