Immunofluorescence labeling of cell surface antigens in Dictyostelium

BACKGROUND: Immunolocalization of cellular antigens typically requires fixation and permeabilization of cells, prior to incubation with antibodies. FINDINGS: Assessing a test protein abundantly present at the cell surface of Dictyostelium cells, we show that in fixed cells, permeabilization extracts almost completely this cell surface antigen. The extent of this artifact is variable depending on the procedure used for labeling and permeabilization, as well as on the antigen considered. CONCLUSIONS: An optimized protocol for labeling both surface and intracellular antigens without significant loss of labeling is proposed.