Direct Evidence for a Receptor-Ligand Interaction between the T-Cell Surface Antigen CD2 and Lymphocyte-Function-Associated Antigen 3

• Published in: Proceedings of the National Academy of Sciences - PNAS 1987-10, Vol.84 (19), p.6864-6868
• Main Authors: Takai, Yasuyuki, Reed, Martha L., Burakoff, Steven J., Herrmann, Steven H.
• Format: Article
• Language: English
• Subjects: Analysis of the immune response. Humoral and cellular immunity; Antibodies, Monoclonal; Antigens; Antigens, Differentiation, T-Lymphocyte - immunology; Antigens, Differentiation, T-Lymphocyte - isolation & purification; Antigens, Surface - immunology; Antigens, Surface - isolation & purification; B lymphocytes; Biological and medical sciences; Cell Adhesion; Cell interactions; Cell Line; Cell lines; Fundamental and applied biological sciences. Psychology; Fundamental immunology; HLA antigens; Humans; Immunobiology; Ligands; Lipids; Lymphocyte Function-Associated Antigen-1; Membrane proteins; Molecules; Receptors; T lymphocytes; T-Lymphocytes - immunology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.84.19.6864

The recognition of foreign antigen by T lymphocytes requires direct contact with cells expressing the antigen. It has recently become clear that T lymphocytes can form conjugates with other cells in the absence of foreign antigen expression. Studies using monoclonal antibodies (mAbs) to inhibit conjugate formation have suggested that a portion of the antigen-dependent adhesion is mediated by T lymphocytes interacting with cells expressing lymphocyte-function-associated antigen 3 (LFA-3), a widely distributed cell surface protein. We have investigated antigen-independent adhesion by incorporating affinity-purified LFA-3 into the lipid membrane of an artificial target cell (ATC; a nylon-matrix vesicle with a lipid membrane). These vesicles are similar in size and density to intact cells, so that conjugates between cells and ATCs may be seen by light microscopy. ATCs expressing a density of LFA-3 similar to that on intact cells were found to form conjugates with T cells, but only if the T cells expressed the sheep erythrocyte receptor, CD2 (T11; LFA-2). Previous studies using mAbs have implicated the CD2 molecule in both adhesion and T-cell activation. ATCs prepared without surface protein or with purified HLA class I protein failed to interact with the CD2-positive T cells, indicating that the adhesion found was mediated by the LFA-3 molecule. Furthermore, mAb against LFA-3 or CD2 was able to block the LFA-3-mediated vesicle-cell interaction, whereas mAb against LFA-1 or HLA failed to inhibit the interaction. These results provide direct evidence that LFA-3 functions as an adhesion molecule by serving as a ligand for the CD2 molecule on T cells.