Scanning immuno‐electron microscopy of human leukaemia and lymphoma cells: a comparative study of techniques using immunolatex spheres as markers

In this study scanning immuno‐electron microscopic (SIEM) techniques were used to identify human leukaemia‐lymphoma cells. Monodispersed polystyrene (latex) beads were conjugated to specific antisera using glutaraldehyde, in an attempt to detect surface antigenic components on a variety of cells of known origin. Antisera, mostly immunoglobulin fractions, against human thymus (T) derived cells, common type acute lymphoblastic leukaemia cells (C/ALL) and surface immunoglobulin (sIg) bearing cells were used to coat latex spheres, while rabbit anti‐mouse Thy‐1 antiserum or whole human‐IgG (γ‐globulin) bound to latex were used as controls in some experiments. The use of SIEM techniques in the direct mode as a simple and sensitive method for labelling surface antigens is described. The disadvantages of the SIEM methodology are also summarized while the requirements for optimal cell preparation using this technique are stressed. The experiments were designed to ascertain whether prolonged fixation of cells could be used prior to incubation of the cells with the marker. In this respect, repeated neutralization of the glutaraldehyde with glycine is essential. SIEM labelling of cells is random and unreliable without adequate quenching with glycine. The heteroantisera used in this study proved to be adequate and insignificant non‐specific attachment and cross reactivity were seen. SIEM adds a further dimension to ultrastructural aspects of immunology and is a potentially useful tool in the study and identification of leukaemia and lymphoma cells.