Mouse/Rat IgM Recombinant mAb (SDT-2061-18-2)

Mouse IgM is the pentameric, high-molecular-weight (≈900 kDa) first-line antibody isotype in Mus musculus, composed of five disulfide-linked μ heavy chains (each ~72 kDa) paired with κ or λ light chains (~25 kDa) and joined by a 15-kDa J-chain that confers its characteristic star-shaped quaternary structure and high avidity for multivalent antigens; it is synthesized and secreted by plasma cells in response to initial antigen exposure, dominates the primary humoral response, serves as the earliest serologic marker of infection, and is evolutionarily conserved to activate complement via the classical pathway through its potent C1q-binding Fc region, while membrane-anchored mIgM (monomeric) on naïve B cells functions as the primary B-cell receptor for antigen recognition and internalization, initiating clonal expansion and immunoglobulin class switching to downstream isotypes.