Indium In 111 Epratuzumab Tetraxetan

**Semantic type:** Amino Acid, Peptide, or Protein|Indicator, Reagent, or Diagnostic Aid|Pharmacologic Substance

**Definition:** A radioimmunoconjugate composed of epratuzumab, a humanized immunoglobulin G1 (IgG1) monoclonal antibody that recognizes the tumor-associated antigen (TAA) CD22, conjugated with the bifunctional, macrocyclic chelating agent tetra-azacyclododecanetetra-acetic acid (DOTA), and labeled with the radioisotope indium 111, with potential tumor imaging activity. Upon administration of indium In 111 epratuzumab tetraxetan, the epratuzumab moiety recognizes CD22, thereby allowing imaging of CD22-expressing tumor cells using gamma scintigraphy. CD22, a B-lymphocyte-restricted antigen expressed as a cytoplasmic protein in progenitor B-cells and as a cell surface protein in mature B-cells, is overexpressed on most malignant B-cells.

**Synonyms:** - INDIUM IN-111 EPRATUZUMAB TETRAXETAN - In 111 LL2 IgG - In 111 Monoclonal Antibody LL2 - Indium In 111 LL2 IgG