Streptavidin is a protein tetramer purified from bacteria with a very high affinity for biotin and is commonly used for the purification or detection of various biomolecules. Streptavidin is immunologically active, inhibiting IL-2 synthesis and CD25 expression in T cells.

Compared to the control group, Streptavidin (2-200 μg/mL) significantly inhibits the proliferation of Lewis T cells towards WF, with an inhibition rate of 76%-83% [1].
In Western blot or ELISA, a concentration of 0.1-1 µg/mL is sufficient.
For immunoprecipitation, a concentration of 1-10 µg/mL can be used.

In Lewis rat models, subcutaneous administration of Streptavidin induced a significant immunosuppressive effect, including reduced T cell proliferation responses to third-party antigens[1].