Hamadan University of Medical Sciences Avicenna Journal of Medical Biochemistry 2345-4113 3 2 2015 12 01 Production and Characterization of Monoclonal Antibodies Against the Dimerization Domain of Human HER2 2 29918 10.17795/ajmb-29918 EN Mohammad Nadri Mohammad Soukhtanloo Amir Hosein Jafarian Mahboobeh Alamdari Mohsen Sisakhti Tayebeh Kianoush Farnaz Zahedi Avval Journal Article 10.17795/ajmb-29918 2015 05 12 2015 05 31 Background: Human Epidermal Growth factor Receptor 2 (HER2), also known as ErbB2 is a 185 kDa protein belonging to the Human Epidermal Receptor (HER) family of tyrosine kinase receptors overexpressed in 20% - 30% of patients with breast cancer. Similar to other members of the HER family, HER2 glycoprotein comprises of multiple domains including an extracellular ligand-binding domain, a single transmembrane domain and a cytoplasmic domain with tyrosine kinase activity. The extracellular domain of HER2 with 632 amino acids is composed of four subdomains (I - IV); subdomains I and III form a ligand binding site, and cysteine-rich subdomains II and IV play an important role in dimerization of the receptor. Materials and Methods: Primarily, BALB/c mice were immunized with a 30-aminoacid peptide as a part of the human HER2 subdomain II. Splenocytes from hyperimmunized mice were fused with myeloma cells (SP2/0), selected in hypoxanthine-aminopterin-thymidine (HAT) medium, and screened by indirect Enzyme-Linked Immunosorbent Assay (ELISA). Secreted MAbs were characterized according to isotypes, reactions with the native HER2 in SKBR3 cells by western blotting, and in tissue sections from HER2 positive breast cancer specimens by Immunohistochemistry (IHC). Conclusions: The results of both western blotting and Immunohistochemistry showed that native HER2 can be detected with 1F1 monoclonal antibody.