Recovery of the contact site A glycoprotein of Dictyostelium discoideum from sodium dodecyl sulfatepolyacrylamide gel and characteristics of monoclonal antibodies against the recovered protein

Monoclonal antibodies were produced against a cell‐cell adhesion (contact site A) glycoprotein of Dictyostelium discoideum , isolated by preparative gel electrophoresis. The glycoprotein was recovered by electroelution from a polyacrylamide gel strip and used for the production of monoclonal antibodies. Four of the five antibodies obtained bound specifically to the protein moiety of the contact site A glycoprotein. The specificities of the antibodies were in striking contrast to those of antibodies raised against the contact site A glycoprotein purified by Triton X‐114 phase separation and DEAE chromatography. The majority of the latter antibodies recognized the carbohydrate moiety of the contact site A glycoprotein and cross‐reacted heavily with other membrane glycoproteins.