Functional studies of stable L cell transfectants expressing intercellular adhesion molecule 1 [ICAM-1]

High molecular weight DNA isolated from human tonsil was transfected into mouse L cells to produce transfectants expressing the human intercellular adhesion molecule [ICAM-1]. The transfected ICAM-1 molecule was highly expressed on the cell membrane and our studies show that the transfected ICAM-1 molecule was a fully functional adhesion protein. All leucocyte subtypes showed specific binding to the ICAM-1 transfectants, their adhesion being inhibited by Fab1 fragments of W-CAM-1 antibody and LFA-1 MoAb (leucocyte function antigen). B cell lines (RAJI, Nalm1) showed the highest degree of ICAM-1 mediated adhesion. Normal lymphoblasts showed comparable levels of binding whilst normal neutrophils (both resting and activated by (N-formyl-methionyl-leucyl-phenylalanine) fMLP) showed the least ICAM-1-mediated adhesion. Despite a significant level of adhesion to ICAM-1 transfectants shown by T lymphoblasts generated in a two way MLR there was no evidence of cytolysis of ICAM-1 transfectants. These studies demonstrate the potential of ICAM-1 transfectants as tools for analysis of the role of ICAM-1 in lymphoid adhesion.