Keyhole limpet hemocyanin (KLH) is a copper-containing respiratory glycoprotein from the hemolymph of the marine mollusk M. crenulata that is involved in oxygen uptake, transport, and release.{68248,68249,68250} It exists as two isoforms, KLH1 and KLH2, and is composed of eight globular functional units that each contain an oxygen binding site and arrange into decamers, didecamers, or multidecamers to form a cylindrical pore.{68248,68251} Due to its immunogenicity, KLH has commonly been used as a T cell-dependent model antigen.{68249,68252} Immunization of mice with a peptide derived from A. baumannii outer membrane protein A (OmpA) conjugated to KLH produces a monoclonal antibody that increases macrophage opsonization of antibiotic-resistant A. baumannii in vitro.{68253} Serum isolated from mice vaccinated with KLH conjugated to 2,4-dinitrophenyl (DNP) and an analog of the tumor-associated carbohydrate antigen ganglioside GM3 exhibits increased IgG antibody titers and induces antibody-dependent cell cytotoxicity (ADCC) in B16/F10 mouse skin melanoma cells expressing a DNP-ganglioside GM3 analog conjugate.{68254} Cayman’s KLH Monoclonal Antibody (Clone 15F7E4G3) can be used for ELISA and Western blot (WB) applications.