Screening of anti-MUC1 antibodies for reactivity with native (ascites) and recombinant (baculovirus) MUC1 and for blocking MUC1 specific cytotoxic T-lymphocytes
Receptors, Pattern Recognition
We report the results of a panel of 56 monoclonal antibodies submitted to the ISOBM TD-4 Workshop for the study of the epithelial MUC1 mucin. We used three forms of the MUC1 as antigen. One form of mucin was the native, highly glycosylated MUC1 isolated from the ascites of breast or pancreatic cancer patients. Two other forms of the mucin were recombinantly expressed in a baculovirus expression system as either fully glycosylated, or underglycosylated. Based on the results of Western blot analysis we were able to group the antibodies into 7 clusters depending on their recognition of the MUC1 forms tested. We then selected several antibodies, representatives of each cluster, to test for the ability to block MUC1-specific cytotoxic T-lymphocyte (CTL) function. We found that antibodies ISOBM-163 and ISOBM-147 blocked cytotoxicity of MUC1-specific CTL against two tumor targets in a concentration-dependent manner.