Direct observation of immunoglobulins on the erythrocyte membrane

A modification of the sublimation procedure for observation of cell membrane exteriors is described. By retaining basic advantages of the freeze-fracture technique, without actual fracturing of the sample, high quality replicas can be produced on which molecules such as immunoglobulins can be identified and mapped on extensive areas of the erythrocyte membrane surfaces. The method can be used for direct observation of antibodies without recourse to labelling with other marker molecules, such as for example ferritin. In addition, direct visualization of clumping of red cells, as induced by such antibodies, is feasible.