The potency (i.e. EC50 for degranulation and tumor lysis) of the EGFR-Vδ2hi-lo bsVHH-albumin construct was ~10 fold lower compared to the EGFR-Vδ2hi-lo bsVHH-Fc perhaps as a result of impaired immune synapse formation when albumin was bound to the engager in this specific orientation. Here, ALB is linked to neoplasm.