CD307e antibody targets the CD307e antigen, also known as Fc receptor-like 5 (FcRL5) or IRTA2. a transmembrane glycoprotein predominantly expressed on B cells. As part of the Fc receptor-like (FCRL) family, CD307e features extracellular immunoglobulin domains and cytoplasmic signaling motifs, enabling interactions with immune complexes and modulation of B cell receptor (BCR) signaling. Unlike classical Fc receptors, FCRL members like CD307e lack direct binding to IgG but regulate B cell activation, differentiation, and tolerance. CD307e is notably upregulated in certain B cell malignancies, such as chronic lymphocytic leukemia (CLL) and multiple myeloma, and is linked to autoimmune disorders like systemic lupus erythematosus (SLE). Its restricted expression on B lineage cells and involvement in pathological conditions make CD307e a promising therapeutic target. Antibodies against CD307e are being explored for diagnostic applications, targeted drug delivery, and immunomodulatory therapies, including antibody-drug conjugates (ADCs) or bispecific antibodies. Research continues to clarify its precise biological roles and potential in precision medicine for B cell-related diseases.