Quantitation of tissue transglutaminase by a sandwich ELISA system

A sandwich ELISA system has been developed to quantitate transglutaminase in human cell extracts. It utilizes affinity-purified rabbit anti-human transglutaminase as the capture antibody and a mouse monoclonal anti-transglutaminase (Birckbichler et al., 1985) as the indicator antibody (together with peroxidase-labeled anti-mouse immunoglobulin). The sensitivity of the assay was less than 1.0 ng/mg cellular protein. Significantly higher concentrations of the enzyme were found in resting versus proliferating or transformed fibroblasts in good agreement with previous activity measurements. The levels of transglutaminase in normal T and B lymphocytes, malignant lymphoid cells and monocytes were also determined.