Humananti-mouse antibody protected ELISA for the quantification of squamous cell carcinoma antigen

Squamous cell carcinoma antigen (SCC) was first isolated from squamous cell carcinoma tissue of the uterine cervix and initially reported as TA-4. The antigen has been characterized as a glycoprotein with a molecular weight between 45,000 and 55,000 daltons. Studies suggest that SCC may function as a protease inhibitor. SCC is expressed in normal epithelium and epithelial tissues. The antigen primarily consists of over ten protein fractions with isoelectric points ranging from 5.9 to 6.6 which are generally divided into two groups: The acidic group with isoelectric points < 6.25, and the neutral group 6.25 or greater. The neutral form of SCC normally remains inside the cell, whereas acidic SCC is easily released from the cell and is often elevated in the serum of patients having squamous cell carcinomas or other nonmalignant squamous cell lesions. It has been proposed that SCC may be involved in the malignant behavior of squamous cell cancers having a role in invasion and/or metastasis. Consequently, SCC levels in the serum are used for monitoring carcinomas of various tissues including uterine cervix, lung, skin, head and neck, esophagus, urothelium, anal canal and vulva. Despite the demonstrated clinical utility of SCC testing, reagents (investigational use only) were no longer available in the US by the late 1990s. Yet, SCC testing continues to be commercially available in Europe and Asia. We therefore, have developed and validated a 96-well microtiter plate formatted ELISA as an option for SCC testing. The ELISA includes protection against human anti-mouse antibodies (HAMA) to a theoretical limit of at least 3.2 mg/mL.