The BSP has made an important contribution to the implementation and acceptance of 3Rs methods exemplified by work to: support the inclusion of the BINACLE in vitro test for tetanus toxicity in tetanus vaccine monographs; develop an in vitro potency assay for human rabies vaccine; and examine the feasibility of a cell-based assay to measure the potency of recombinant erythropoietin in vitro. Here, EPO is linked to tetanus.