Characterization of Glass Adherent Human Mononuclear Cells

Although adherence to glass is commonly used to prepare monocyte monolayers from blood mononuclear cell suspensions (1–3), several recent reports suggest that lymphocytes are also able to adhere to either glass or glass substitutes like nylon or tissue culture dishes (4, 5). Using morphologic criteria, Levis (4) reported considerable lymphocyte binding to glass coverslips placed in mononuclear cell suspensions. Although many of the lymphocytes could be detached by rigorous mechanical washing, this resulted in a loss of monocytes as well. Rosenthal (5) has suggested that adherence to glass can be used to deplete selectively lymphocyte preparations of antibody-forming or “bursal-derived” (B)2 lymphocytes. Similarly, Boldt (6) has demonstrated that nylon columns can remove from a suspension of blood mononuclear cells a population of lymphocytes which are “highly responsive” to concanavalin A. These observations indicate that monocyte monolayers prepared by adherence of blood mononuclear cells to glass or tissue culture dishes may be contaminated by considerable numbers of lymphocytes. It has been recognized that differentiation of monocytes and lymphocytes on morphologic criteria alone is difficult (7). This study was undertaken to determine the identity of cells adherent to surfaces in the presence and absence of serum by using several criteria including morphology, membrane receptors, and response to mitogens.