Characterization of activated lymphocyte-tumor cell adhesion

• Published in: Journal of leukocyte biology Vol. 67; no. 6; pp. 847 - 855
• Main Authors: Neeson, Paul J., Thurlow, Peter J., Jamieson, Gary P.
• Format: Journal Article
• Language: English
• Published: United States Society for Leukocyte Biology 01.06.2000
• Subjects: Animals; Antigens, CD - biosynthesis; CD58 Antigens - biosynthesis; Cell Adhesion; Cell Adhesion Molecules - biosynthesis; HT29 Cells; Humans; Intercellular Adhesion Molecule-1 - biosynthesis; intercellular adhesion molecule‐1; K562 Cells; leukocyte function antigen‐1; LFA-1 antigen; LFA-3 antigen; Lymphocyte Activation - immunology; Lymphocyte Function-Associated Antigen-1 - biosynthesis; Mice; Tumor Cells, Cultured
• ISSN: 0741-5400; 1938-3673
• DOI: 10.1002/jlb.67.6.847

This study demonstrates the variable expression of ICAM‐1 and leukocyte function antigen‐3 (LFA‐3) on four tumor cell lines (COLO526, K562, Daudi, and HT‐29). In addition, phorbol ester (PMA) activation of lymphocytes modulated LFA‐1 from a uniform to a clustered surface distribution; whereas after treatment with high levels of Mg2+ ions, the unique epitope for high‐affinity LFA‐1 was identified using clone Mab24. Using a flow cytometric adhesion assay it was demonstrated that PMA‐activated lymphocytes formed conjugates with COLO526 and Daudi, and that these conjugates were inhibited by anti‐CD2 with varying inhibition by LFA‐1 clones MHM24 and 25.3.1. When lymphocytes were induced to express the high‐affinity form of LFA‐1, conjugates were identified with COLO526, K562, and Daudi and these conjugates were sensitive to the presence of both CD2 and LFA‐1 antibodies. Further studies using confocal microscopy confirmed significant adhesion between peripheral blood lymphocytes pre‐treated with either PMA or high levels of Mg2+ and the adherent cell line COLO526. In conclusion, this unique study has demonstrated for the first time the important role of the active form of LFA‐1 on the lymphocyte cell surface for conjugate formation with an ICAM‐1‐expressing tumor cell; also, two pathways of cell signaling were identified for conjugate formation to occur. J. Leukoc. Biol. 67: 847–855; 2000.