T (Thomsen-Friedenreich) and Tn epitope location and their spatial relations to adhesion plaques on human breast carcinoma cells: immunogold-silver staining studies at scanning electron microscopic level

Abstract

T and Tn are pancarcinoma epitopes (EPs) which can be immunodetected in about 90% of adenocarcinomas (CAs). To study the location of T and Tn EPs and their relations to adhesion plaques on CA cells, immunogold-silver staining method was employed at scanning electron microscope (SEM) level. Human breast CA cells grown on coverslips were fixed in paraformaldehyde and glutaraldehyde, reacted with cocktails of monoclonal antibodies against T or Tn EPs, followed by incubation with 10 nm gold conjugated goat anti-mouse immuno-globulins. The positive gold particle labelling was amplified with silver enhancement solution, and the specimens were then routinely critical point dried, sputter-coated with palladium and observed under SEM. The studies show that T and Tn EPs are not randomly distributed on CA cell surface; they are aggregated at the adhesion plaque area. These results confirm that T and Tn EPs play roles in CA cell adhesion, and suggest that they may represent the initial points of contact by immuno-effectors and therefore can be utilized in immunointervention and anti-adhesion therapy against CA.